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I'v,' ,.' ,"i S!,Sm THE UNIVERSITY .r ^ > OF ILLINOIS LIBRARY Gil HG>3 CENTRAL CIRCULATION BOOKSTACKS The person charging this material is re- sponsible for its renewal or its return to the library from which it was borrowed on or before the Latest Date stamped below. You may be charged a minimum fee of $75.00 for each lost book. Theft, mutilation, ond underlining of books are reasons for disciplinary action and may result In dismissal from the University. TO RENEW CALL TELEPHONE CENTER, 333-8400 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN JUN 3 w 1996 NOV 2 2 1936 FEB 2 5 1997 PFC 1 4 2005 OCT 3 1 2006 When renewing by phone, write new due date below previous due date. L162 THE UNIVERSITY OF ILLINOIS LIBRARY (oW H(o3 Z Latest Date stamped below. A charge is made on all overdue books. University of Illinois Library Digitized by the Internet Archive in 2017 with funding from University of Illinois Urbana-Champaign Alternates https://archive.org/details/elementaryanatom00hitc_0 (=( I 'H i^-Z PREFACE. i This work is offered to the public in the hope that it has some desirable features as a text-book, not found in any of the able elementary works on Anatomy and Physiology now ex- tant. One is, the introduction of more of microscopic anat- omy than is usual. Another is, a large addition on Com- parative Anatomy, which is now become a science of great importance. A third is, the Religious Applications of these sciences ; which, although all will acknowledge to be emi- nently appropriate, we have found in no elementary treatise. We make no pretensions to distinguished attainments or reputation in these sciences, as a reason for writing this book. But both of us have for a great number of years been in the habit of hearing recitations and giving lectures upon them in the College and the Academy, and we ought to know what sort of a text-book is needed. But we dare not boast that we have come up to our ideal. We have tried to give a condensed yet clear exhibition of the leading principles and facts, which are detailed in such works as Carpenter’s Human Physiology, his Comparative Physiology, Hassall’s Microscopic Anatomy, Griffith and Henfrey’s Micrographic Dictionary, Peaslee’s Histology, Todd and Bowman’s Physiological Anatomy, Wil- son’s and Gray’s Anatomy, Draper’s, Dunglinson’s, and Dal- ton’s Physiologies, Van Der Hoeven’s Zoology, and the works of Cuvier, Owen, Agassiz, Wyman, Leidy, and Wagner on Comparative Anatomy. Through the liberality of the publishers we are able to pre- sent unusually full illustrations of subjects, which could other- wise be only imperfectly comprehended by the learner. Many of the drawings contain more minute details of the parts represented than are described in the text. The in- structor can require these to be recited or not, as he pleases, according to the age and ability of the pupil. So as to the parts on Comparative Anatomy, as they are distinctly sepa- rated from the rest, they can, if desired, be passed over in re- citation. At the earnest solicitation of my son, my name stands first on the title-page. But justice requires me to state that most of the body of the work has been prepared by him. I have supposed it most appropriate that it should be so, since he has, and I have not, passed regularly through the medical school. Yet perhaps the public may have some confidence in my judg- ment as a teacher for more than forty years, in shaping the materials so as to be best adapted for purposes of instruction. But aware, in some measure, of our deficiencies and imperfec- tions, neither of us, in sending forth the work, feels it to be beyond criticism and improvement. In a field so wide, where so many are pushing their investigations, and the highest authorities so frequently change their views, we do not ex- pect to avoid all mistakes ; but in our successive editions, we shall correct all errors which we find, and try to incorpor- ate the new discoveries. Edward Hitchcock. Amherst College July, 1860. CONTENTS. PAGB Preliminary Definitions and Principles 5 CHAPTER I. Osteology and Syndesmology — Description op the Bones and Ligaments 31 CHAPTER II. Myology — Description op the Muscles lOY - CHAPTER III. Splanchnology — Description op the Digestive Organs. 155 CHAPTER IV. Angiology — Description op the Heart, Blood, and Blood-Yessels, 201 CHAPTER V. Pneumonology — Description op the Organs of Breathing 244 CHAPTER VI. ICHOROLOGY — DESCRIPTION OP THE ORGANS OF SECRETION 282 VI CONTENTS / CHAPTER VII. PAGE Neurology — Description of the Brain and Nerves 316 CHAPTER VIII. The Inlets to the Soul — The Senses 361 CHAPTER IX. Reugious Infeeences from Anatomy and Physiology 420 DEFINITIONS AND PRINCIPLES. 1. All the objects in the material world are divided into Organic and Inorganic. 2. Cells, Membranes, and Fibers. — In organic bodies, the matter composing them is arranged in the form of cells, mem^ branes, and fibers, variously combined. In inorganic bodies, though the particles are often arranged with mathematical precision in particular modes, cells, membranes, and fibers are not formed. 3. Life. — The principle of life is always associated Avith or- ganic, but never with inorganic bodies. 4. Examples of Organic and Inorganic Objects. — Or- ganic bodies embrace Animals and Plants ; every thing else in the material world is inorganic, as, air, water, minerals, rocks, and soils. 5. Man the Head of the Animal Kingdom. — ‘‘Man is the end toward which all the animal kingdom has tended from the first appearance of the Palaeozoic fishes/’ — Agassiz and Gould. 6. Anatomy and Physiology. — Anatomy is the science that Questions. 1 Give the two kingdoms of the material world. 2. What is the arrange- ment of matter in organic and inorganic bodies? 3. With which is life associated? 4 State some examples of organic and inorganic bodies. 5. Why is man placed at the head of the animal kingdom ? 6. Define Anatomy. G II l T C ir C O CMC ’ S ANA T O .M Y describes the different organs of animals. Physiology describes their functions, or uses. If the organs of man alone be de- scribed, the science is called Human Anatomy and Physiology. If the description embrace the lower animals, it is called Com- parative Anatomy and Physiology. 7. Another definition of Anatomy, is the science of Organ- ization ; and of Physiology, the science of Life. 8. Animal and Vegetable Anatomy and Physiology.— There are also such sciences as Vegetable Anatomy and Physiology. Indeed, there is a strong analogy between the organs of plants and animals, and their uses. Nor is it easy always to draw the line between plants and animals, where they approach the nearest to each other. 9. Intimate Connection of Anatomy and Physiology. — Few writers confine themselves to the structure of animals, when treating of their anatomy, but treat also of the function of their organs ; and the same thing is still more generally true of writers on physiology. We do not separate these sciences in this treatise. 10. Fifteen Chemical Elements in the Unman Body. — Of the sixty-five chemical elements or simple bodies known to exist, only fifteen have been found as normal constituents of the human body. The following is the list : — 1. Oxygen, 2. Hydrogen, 3. Carbon, 4. Nitrogen, 5. Sulphur, 6. Phosphorus, 'I. Calcium, 8. Magnesium, 9. Sodium, 10. Potassium, 11. Chlorine, 12. Pluorine, 13. Silicon, 14. Iron, 15. Manganese. 11. Carbon, Hydrogen, Oxygen, and Nitrogen. — The first three of the above elements are found in all the solids and fluids of the body, without exception. The first four occur in all the What is Physlolofry ? When is the term comparative applied? 7. Oive. a more con- cise definition of AnatoTny and Physiology. 8. Describe animal and vegetable IMiy- Biology. 0 Speak of the close relationship between Anatomy and Physiology. State the whole nnmber of chemical Elements, 10. State those which are found in the human body. 11. Where are the first throe found? Nitrogen also ? AND PHYSIOLOGY. 7 solid parts, and in all the fluids except fat. They form the chief and most important ingredients in animals and plants. 12. Sulphur and Phosphorus, illagiicsium, Sodium, Pot- assium, CMorine, Fluorine, Calcium, Silicon, Iron, Man- ganese, — With scarcely an exception, these elements exist in the body as compounds; that is, two or more of them are combined, as in water, in oxyds, and in various salts. Sul- phur and phosphorus exist in albumen and fibrine, as well as in the brain, about yjoth of its weight being phosphorus. Bones are more than half made up of Phosphate of Lime, and they contain a small per cent, of Phosphate of Magnesia. Sodium, in the form of a chlorid (common salt), is found in every solid and fluid of the body. Potassium occurs as a chlorid in the muscles, and as an oxyd in salts. Chlorine forms chlorohydric acid by combining with hydrogen in the gastric juice. Fluorine exists in the bones in a minute quan- tity, combined with calcium. Silicon is found in small quan- tities in hair, wool, and feathers, as silica. Iron forms about the 2000th part of the blood,*and it exists also in the muscles, hair, and milk. Manganese, in small quantities, has been detected in bone, and perhaps in the hair. 13. Copper, lead, and Arsenic. — Copper, lead, and arsenic have been detected in minute quantity in human flesh. But it is not probable that they are normal constituents. 14. Inferences. — From these facts we learn that our food and drink should contain the fifteen ingredients above described. Milk and eggs are the only articles that do contain them all ; and hence, the importance of variety in diet. And the fact that we are obliged to use ten mineral ingredients in our food, shows the absurdity of a prevalent prejudice that no mineral should ever be taken as a medicine. 15. Immediate Principles. — As they exist in the body, the 12. State in what organs Sulphur and Phosphorus are found. What is one of the prin- cii)al ingredients of bones ? Where is Chlorine found ? Fluorine ? Silicon ? In what parts of the body is Iron found? 13. What is to be said of Copper, Lead and Arsenic? 14. What should our food contain? Are mineral ingredients always poisonous ? 15. De- fine Immediate Principles. 8 HITCHCOCK’S ANATOMY fifteen elements above described form a largo number of com- pounds, called Immediate Principles, or Organic Radicals. They exist naturally, and can be separated anatomically, that is, mechanically, from one another ; but the divisions can bo carried no further 'without chemical decomposition. A few elementary substances found in the system, as, oxygen, hydro- gen, and nitrogen, are sometimes called Immediate Principles. 16. Immediate Prineiples Chemically Grouped. — We arc certain that eighty-four of these principles have been found in the human system. If we group them according to their chem- ical characters, they will fall into the following divisions. Half of them are the result of the waste or metamorphosis of the substance of the body ; ll:o other half exist independently of any such change. 1. Gascons^ and not saline : Oxygen, Hydrogen, Nitro- gen, Carbonic Acid, and Water. 2. Salts : Chlorids (2), Fluoride of Calcium, Hydrochlo- rate of Ammonia, Carbonates (4), Bicarbonate of Soda, Sul- phates (3), Phosphates (7), Lactates (3), Oxalate of Lime, Urates (5), Hippurates (3), Inosate of Potassa, Pneumate of Soda, Taurochlorate of Soda, Hyocholinate of Soda, Gly- cocholate of Soda, Oleate of Soda, Margarate of Soda, Stear- ate of Soda, Caproate of Potassa, Soda, &c. 3. Acids: Lactic, Uric, Hippuric, Pneumic, Lithofallic, Margaric, and Stearic. 4. Neutral Nitrogeyious Comi^ounds : Creatine, Urea, Cystine, and Creatinine. 5. Neutral Non-Nitrogenous Compotmds : Sugar from the Liver, and Sugar of Milk. 6. Fatty and Saponaceous Compounds : Cholesterine, Oleic Acid, Stearic Acid, Oleine, Stearine, &c. (13.) 7. Coagulahic Principles : Fibrine, Albumen, Caseine, Clobuline, Musculine, Osteine, Keratine, Hematine, &c. (18.) 10. Stuto tho nutnbcT of these principles that have been already found. What are one half of them derived from ? Give tho first group, or the gaseous ones. State th« bulls. The Acids. The 4th, Dth, Gtli and 7tb classes. AND PIIA-SIOLOGY. 9 17. Immediate Principles Physiologically Grouped. — • If we group the preceding substances according to their phy- siological relations, we might, with Dr. Carpenter, bring them all into four divisions. 1. Hlstogenetic Substances^ or such as are converted into animal substances, and are nitrogenous. 2. Calorific Substances, mainly intended to produce heat, and are non-nitrogenous, as, sugar and oils. 3. The co7nponents of the living animal substance, 4. Excrementitious Substances, formed Avithin the body, and thrown out of it. 18. Other Probable Principles. — Quite a number of other substances have been detected in the human system, Avhich some regard as immediate principles. But it is safer to Avait till further examination has removed doubt. 19. Several of the above principles are capable of crystal- lization, and are some- times found in that state in the body. Figs. 1 and 2 shoAV two exam- ples of these crystals, the first of Hippuric acid, and the other of Creatine. 20. To go into minute details respecting the im- mediate principles above described, Avould occupy too much space in a work like the present. But a fcAV statements respect- ing the most import- 17. AAHiat are the Groups of these substances when physiologically grouped ? Who is the autliority for this? Define the llistogenetic and the Calorific group. What are ex* creincntitious substances? Are there any other principles in the body? 1* Fig. 1 . 10 HITCHCOCK’S ANATOMY ant of them seem desir- able. 21. Oxj ‘rni. — Oxy- gen is regarded as an immediate principle only when it exists in a free state, as it does in the blood, which, in an adult, contains sixty- one grains : nine and a half cubic inches be- ing found in the arte- rial, and fourteen and a half in the venous blood. An adult consumes in a year about eight hundred pounds of oxygen. An inhabitant of a mountainous region 18,000 feet above the sea (in Potosi) consumes, however, only two thirds as much as one upon the sea-shore. 22. Hydrogen and Nitrogen. — Hydrogen is found in a free state in the stomach and some parts of the intestines, and nitrogen in the lungs, blood, and intestines. 23. Carbonic Acid. — Carbonic acid is found in the lungs, the alimentary canal, the blood, and urine. 24. Water; Cubical Size of the Body. — Water enters into the composition of every fluid, and every solid in the body. The bulk of the body, upon an average, is equal to a cube of a little more than sixteen inches on a side ; and the amount of water equals a cube a little more than fourteen inches on a side, or nearly three fourths of the body. Every part, ex- cept bone, enamel, teeth, tendon, dry cuticle, and elastic tis- sue, is more than half water. 21. How imicli Oxygon by woitrbt is I’oiind in the body? What bulk of oxygen is found In the venonsand wliat in the arterial blood ? How much does an adult consume by re- sidration nnd (»therwise in a year? What effect does elevation above the sea have upon the ainoimt eonsurned? 22. State bow Hydrogen and Nitrogen are found. 23. Carbonic acid .also. 24 How important a constituent is water? Give the size of the body if re- duced to a cube. If this cube were water, how largo would it bo ? Fig. 2. AND r II Y S I O L O G Y . 11 25. Amount of Water Consumed Yearly by an Adult. — An adult drinks about fifteen hundred pounds of water yearly; and throws ofl* through the various waste-gates nineteen hun- dred pounds. The difficulty of accounting for the four hun- dred pounds has led some to suppose that water is formed in the system by the union of oxygen and hydrogen. 26. Common Salt in the Body. — The salts that have been enumerated, are found in almost every part of the body. Com- mon salt (Chlorid of Sodium) is found in every fluid and solid, except enamel. The whole amount in man h 277 grains. It subserves many important uses. 27. Carbonate and Phosphate of Lime, Ac. — Carbonate of lime exists in considerable quantity in the bon.es, along with a much larger quantity of the phosphate of lime, and a small amount of phosphate of magnesia, and of fluoride of calcium. These salts, except the fluoride, are found in most other parts of the body. 28. Acids, Salts, &c . — Most of the acids and salts, the neu- tral nitrogenous compounds, the sugars, the fatty and sapona- ceous compounds, exist, or are formed in the fluids of the body, and though numerous (forty-two in all), their quantity is comparatively small. They are mostly formed by disassimi- lation in the body, and hence only their elements need to exist in our food. 29. Sugar in the Body. — Only two kinds of sugar exist, or are formed in animals. Grape sugar is found in the liver, in some of the veins, and other organs. In the disease called Diabetes, its quantity is very much increased, and, in fact, an excess of sugar in the system is a sign of serious derangement. 30. Fats in the Body. — The fatty principles, cholesterine, oleine, etc., exist in the body in cells, in chemical combina- 25. How much water does a man consume in a year? How much is thrown off during the same time? Explain the reason. 26. Where docs common salt occur in the body? How many grains exist in the body? 27. la what ])arts of the body do Carbonate and Phosphate of Lime occur ? 28. How many acids and salts are found ? State how they are formed. 29. How many kinds of sugar are found in animals? What does an excess of sugar indicate ? 30. How do the fats occur in the body ? 12 HITCHCOCK’S A X A T O ISr Y tion with other substances, and as oil drops or fat globules not inclosed. These principles are mostly taken as food into the system, but they are most probably also formed there from elements ; certainly, the liver has this power. One tenth of the brain is composed of fat ; and it is only in the last stages of emaciation, that this supply is exhausted. 81. Assiniilalioii Necessary. — The principles thus far de- scribed, constitute but a small proportion of the animal frame. Bat the organic, or coagulablc principles, enter largely into its composition. Indeed, they form the principal source of nourishment. The most important of these principles (albu- men, fibrine, and caseine) are in a fluid state in the body ; the others are solid, or dernisolid. Though the materials for their formation must exist in the food, yet there is reason to suppose that the process of assimilation is necessary, to trans- form them into these principles. 32. Albumen, Albuminose, Cascinc. — Coagulation takes place when a liquid, or semi-liquid, passes into a solid state. The white of an egg gives a good idea of one kind of albumen (ovalbumen). Seralbumen exists in the blood, and in other liquids of the body. Albuminose is found in the same fluids, and has been, till of late, confounded with albumen. It is formed in the upper intestines, but when it passes into the blood, it becomes mostly albumen, sometimes musculine, fibrine, etc. Animal caseine is found only in milk, being most abundant when an animal diet is used. It contains from four to six per cent, of phosphate of lime, and hence the im- portance of milk for young animals, that their bones may be developed. 33. Fibrine, liliisculinc, Globuliiie, Osteinc, and Gluten. — Fibrine is found in the blood, and when it coagulates, the mass ij fibrous, the process being called fibrillation. It is this prin- ciple chiefly that causes blood to coagulate, the great importance Is f:it formed in tlio body, or taken in from tlie food? 81, State the three most im- I»ortant orpranic principles. 82. Define congnlation. What is ovalbumen, seralbumen and albuminose? In what is caseine found ? What imjxn-tftut ingrwlient does it contain ? 88. Where D fibrine found ? What causes coagulation of the blood ? What practical beno- lit is derived from coagulation ? AND PHYSIOLOGY. 13 of \vliicb in arresting dangerous hemorrhages is well known. Coagulation appears to be a vital process, that is, dependent on life for its development, and not on chemical laws only. It can be j^revented by any thing that destroys life, such as poisons, or a temperature too high, or too low. Fibrine does not exist in the muscles. That which has been called such is muscu- line, which is endowed with the vital property called contractil- ity. Globuline occurs only in the red corpuscles of the blood. Osteine is the substance from Avhich gluten is made, by the action of boiling water, for gluten does not naturally exist in the body. Osteine is the essential organic element in bone. 34. Hemal inc. — Hema- tine is the coloring matter of the blood, and though iron is found in connec- tion Avith it, all the iron can be abstracted without destroying the color. Hence, that can not de- pend on the iron. He- matine is probably pro- duced from certain red crystals, occurring in the red corpuscles. A group of these crystals is here shown. 85. Proteine Compounds. — All the organic or coagulable principles contain nitrogen, or rather, are composed essen- tially of oxygen, hydrogen, carbon and nitrogen. Hence, their value as food, since a greater part of the body is composed of these elements. Albumen, fibrine, and caseine have been termed Proteine Compounds, for they can easily be changed Is fibrine found in muscular tissue ? What is the proximate principle of muscular tis- sue? Where does globuline and osteine occur? 34. What is the coloring matter of the blood? lias iron any thing to do with its color? What is the Ilematine produced from ? 35. What four simple elements make up all the organic principles ? Why are albumen, etc., termed Proteine compounds ? — Fig. 3. H HITCHCOCK’S ANA T O M Y into Proteine, a substance, however, which docs not exist in nature, but results from the decomposition of the principles above named. ^ HISTOLOGY. 36. Organic and Inorganic Structure.— Animals and plants have a structure different from that of minerals when we examine them with the microscope. The former is called Organic, and the latter Inorganic Structure. 37. Vitality the Cause of Organization. — Vitality, ortho principle of life, or the Vital Force, is the cause of organi- zation. The nature of life is indeed involved in obscurity ; but its effects are manifest, and among them is organization : al- though some have maintained, but without good reason, that the vital force is nothing but a peculiar manifestation of heat, mechanical force, chemical action, galvanism, etc. 38. Elementary and Primary Tissue. — The simplest forms of organized structure are three. 1. Simple Membrane. 2. Simple Fiber. 3. Cells. These organic forms physiologists denominate Elementary Tissue. When united, they form Primary Tissue. 39. Histology; Proportion of Tissues in the Body. — Histology is the science of Tissues. Tissue forms nearly the whole of the solid portions of the body. By means of the mi- croscope, they have been examined with great care, and de- scribed. 40. Fluids of the System; Ilygrology. — Before entering upon a description of the tissues, it seems desirable, at least, to enumerate the different fluids found in the system, though a 80. Define organic and inor ^ " o C 50. Milk.— Milk, a glandular secretion, showing under the mi- croscope an immense number of fat globules, suspended in a clear fluid, as in fig. 4. 51. Saliva . — Saliva, a secretion chiefly from the parotid and submax- illary gland into the mouth, to assist in diges- tion. 52. Bile. — Bile, a greenish or brownish bitter fluid, secreted by the liver to assist in digestion. 53. Pancreatic Jtiicc.^ — -Pancreatic fluid, a colorless, taste- less, but somewhat alkaline fluid, secreted by the pancreas to aid in digestion. 54. Urine, — Urine, secreted by the kidneys. 55. Tears. — Lachrymal fluid for lubricating the eyeballs, secreted by the lachrymal gland. 56. Oil and AVax. — Sebaceous secretions, fatty fluids thrown out by what are called the sebaceous follicles of the skin, to keep it moist. 57. Sweat. — Perspiration, or sweat, a colorless, watery 40. Whut is tlio Intestinal fluid ? 50. How does milk appear under the microscope? .51. What is the origin and use of saliva? 52. State the secretion of the liver. 53. &c, Describe I’ancreatic Juice. Urine. Tears. Oil and Wax. 57. From what glands is sweat j)roduoed ? AND r II Y S I O L O G Y . 17 fluid, with a saltish taste, and having odor, secreted from the perspiratory glands. Elementary Tissues. 58. Simple, or Basement Membrane.— 1. Simple Mem- brane, This is usually a structureless layer of coagulated albumen, often not more than 20000 th of an inch thick. It forms the walls of all cells, and is also spread out, as an in- ferior layer of the skin and mucous membrane, and is then called basement membrane. It is the most simple of all the tissues, yet it is the agent of secretion, and sometimes of ab- sorption, and these Professor Peaslee considers as its vital properties, though of a low grade. 59. Imbibition. — Simple membi-ane also possesses the re- markable property of allowing fluids to pass through it when it is placed between two fluids ; the effect depending in part upon the electro-chemical relations of the substances, but not, as generally supposed, on the difference of specific gravity of the liquids. This is called endosmose and exosmose, or Imbibition, and is the principal means by which fluids are made to pass from one part of the system to another, where no distinct vessels are provided for that purpose. 60. Simple Fiber. — 2. Simple Fiber, This consists es- sentially of threads of coagulated fibrine, whose average diameter is about 8 smooth of an inch thick. It does not appear to be a permanent constituent of the body, but only a basis for the development of the more complicated tissues. A good example of the simple fiber may be seen in the membrane lining the inside of an egg shell, as in Fig. 5. Fig. 5. 58. What is simpl© membrane ? IIow thick ? Where is it found ? What other name is given to it? 59. Describe Imbibition. What purpose does it effect? 60. Dcsoribo simple fiber. Its size. Where best seen ? 18 HITCHCOCK’S ANATOMY 61. Shape of Cells.— 3. Cells. Theso aie merely mem- branous bags, or vesicles, from i to ou'ootb of an inch in diameter, filled with some kind of liquid, or solid substance. When free, the form is spherical, or spheroidal, as in Fig. 6. But, as they press against one another, they are brought into a polyhedral form, as in Fig. 7, showing a group of fat ve- sicles. Fig. 6. Fig. 7. 62. Contents of Cells; Granules; Nucleus anil Nucleo- lus. — The fluid of cells is transparent, except in the case of blood. In it there generally float an immense number of gra- nules, having no investing membrane, but sometimes they are thus invested. Each cell has also a nucleus and a nucleolus ; the first being a globular, or lenticular body, from e o'o oth to g o‘ooth of an inch in diameter, attached to, or imbedded in the wall of the cell, though some are free. The nucleolus is a granule within the nucleus. Both are shown, as well as the common granules, in Fig. 6. 63. Appendages of Cells. — Sometimes cells have a sort of tail attached to them, and are hence called caudate, as in Fig. 8. Sometimes, too, they are stellate, as in Fig. 9, show- ing the pigment cells of a frog’s foot. Cl. Define cells. What is the original form of them ? IIow do they acquire the poly- hedral form? C2. Explain nucleus, nucleolus and cell wall. 63. What arc the appendages of cells? 64. Cytogenesis . — The cell is the most important of the ele- mentary tissues, for, by its multiplication, most of the other 64. Give the process by which cells increase and form tissnei. 20 HITCHCOCK’S A X A T O ]Sr Y Fig. 10. tissues in animals and vegetables are made up. Tliis is called cytogenesis. The increase usually takes place by duplicative subdivision, which is shown on Fig. 10. The cell a a first becomes elongated, as at 6, and then it divides at c c. The subdivision going on will give an increase in rapid ratio — 2, 4, 8, 16, 32, etc. Fig. 11 shows an example of this division, A, B, C, D, in its earlier stages, and E, F, G, II, in its more advanced condition. Sometimes cells multiply by the development of new cells in the interior. In this case the nucleus subdivides into two or more portions, which at length fill the original cell, as is shown in Fig. 12. Some- times cells are formed by the expansion of homogeneous Fig. 11. A B c D granules into cells ; or they are even produced in the midst of a formative fluid (called a blastema), poured out from the blood. Hoscrlbo tho modo of foruitttion as Illustrated in Figures 11 and 12. What is the Blasteinu? AND PHYSIOLOGY. 21 65. It is in these Avajs that most of the tissues of the body are built up, and the animal enlarges to its full size. It has been maintained that all the tissues orig- inate in cell develop- ment. But, in some cases, simple fibers and membranes seem to be formed directly out of an organizable s u b - stance, without the in- tervention of cells. 66. Vital Force of Cells; Chemical Trans- formations; Vitalization of the Cells; Change of Form; Development of Nerve Force.— The multiplication of cells is one of the manifestations of the vital force inherent in them. Another is the chemical transformations exerted upon the con- tents of the cell in some instances, whereby new products are generated. Another is the vitalization of a portion of the cell contents, whereby they are able to produce new cells. Another is permanent changes of form in connection with growth. Another is temporary changes of form, ac- companied with sensible motion, as in the oscillatory move- ments of the leaves of Hedysarum gyrans, and the fold- ing of the leaves of the Mimosas upon touch. Finally, the development of nerve force from cells, by which all the bodily operations may be modified, and which is intimately connected with mental agency. 67. Periods in the Life of the Cells. — In cell life there is a Fig. 12. 65. Show how the tissues of the body are made up. 66. Mention the different changes which cells undergo. TI I T C II C O C K ’ S ANATOMY O') period of augmentation, another of perfection, another of de- cline, and, finally, one of cessation. So long as vitality can use chemical and physical agencies for building up the system, they tend to its preservation, but, when life ceases, they tend to its destruction, not, as is generally thought, because the vital principle has not the power of resisting these agencies, but because it can no longer turn them into the channel for pre- serving the system. PRIMARY TISSUES. The chief mass of the animal system is made up of the ele- mentary forms that have been described, variously combined so as to form plexuses and webs, which are called primary tissues by some, and compound tissues by others. They are differently classified by different writers. The arrangement Avhich follows is that of Professor W. B. Carpenter : 1. Simple Fibrous Tissues. 68. White and Yellow Fibrous Tissues.— This embraces the white and yellow fibrous tissues, as well as the areolar or connective tissue of other writers. The white fibers are from ^Vooth to the 2 0^-0 6 A of an inch in diameter, and form the tendons, ligaments, and fibrous membranes. (Fig. 13.) The Fio 13 Fig. 14 t}l. Give the four difTerent periods in the life of cells. 68, Give the size of the fibers of while and yellow fibrous tissues. AND PHYSIOLOGY. 23 yellow fibers are about o^h of an inch in diameter and form a part of the larynx, and the middle coat of the arteries. 69. Areolar Tissue. — The areolar tissue consists of fibers of white and yellow tissue interwoven, so as to leave irregular spaces, or areolae, between them. This tissue originates from cells, as is shown in Fig. 16. The areolar tissue is more widely diffused than any other in the body, so that if it were possi- ble to remove all but this one, the form of the part would be preserved. It surrounds all the arteries and veins, the nerves, muscles and internal organs ; and it forms one of the layers of the skin and mucous membrane. Fig 15. Fig. 16. 2. The Fibro-Cellular Membranes. 70. One of the layers of the skin, of the mucous membrane, and the serous and synovial coat that lines the shut cavities of the body, is composed of interwoven fibers of simple basement membrane , and of one or more layers of cells upon the free 69. What is the composition of areolar tissue? What of its abundance in the body? Where is it principally found ? 70. Describe the fibro-cellular membrane. 2 24 II ] T O If C OCR’S \ N A T O V surface. This is tlic fibro-ccllular membrane or tissue. Its position and character will be l)etter understood when the parts above referred to have been described in subseej^uent sections. 3. Cellular Tissues. 71. Fat and Cartilage. — These embrace the adipose tis- sues, Fig. 17, and the cartilaginous, Fig 18. The first is the usual form of fat, wherever it occurs in the system. It retains the pure form of the primitive cells. In cartilage, also, these cells sometimes exist alone, but more frequently they are inter- woven with fibers, as seen by the figures. 4. Sclerous Tissues. 72. Bones and Tectli. — These constitute the bones and teeth, and are composed of an animal basis of fibers and cells ce- mented together by phosphate and carbonate of lime. Fig. 19, which is a transverse section of one of the bones of the arm, will give an idea of the arrangement of the animal matter, tlie earthy part having been dissolved by acid. Fig. 20 shows a transverse section of tlie shoulder blade, exhibiting: tlie dark spaces called laciiiun. 71. Di’.scribo fat uiul carl.ila^o. 7'2. Wliat is the composition of tlie bones and tho teeth ? 73. What are tho cui»illarie8 and absorbents? Give tho size of the capillaiios. AND PHYSIOLOGY. 25 Fig. 19 73 . Capillaries and kig 20 Absorbents. — These form those minute blood vessels called capillaries, and others called lym- phatics or absorbent ves- sels, which exist in every part of the body, and are distinct from, al- though connected with, the arteries and veins. The capillaries c 0 n - nccting these are from 2Jooth to 37’ooth of Tr T T C IT C O C K ’ S A N A T O Y Fig. 21. an inch in diameter, less often than tlie Idood cor- puscles. In some other animals they are larger, as may be seen in the capillary plexus of a frog’s foot, shown in Fig. 9. The lymphatics abound with valves, may be seen in Fig. 21. G. Muscular Tissue. ul. M ripe (I and iSnmolli Muscle. — This tissue is made up of two forms of fiber, the striped and unstriped. The stripes in the first form run both transversely and longitudinally, as may be seen Fig. 22. in Fig. 22. When separated longitudinally, the fibrillas have a beaded appearance, each bead being in fact a cell, as is here represented in Fig 23, which shows the cells a when most relaxed, and b when most contracted. Muscular fiber is capable also of being divided crosswise in the direction of the transverse striae into discs, as seen in Fig. 24. Both the striated (striped) and non-striated muscles originate in cells. Figs. 25 and 26 show their development. 75. Myotility. — The grand peculiarity of muscular tissue is its power of contraction — a phenomenon as mysterious and wonderful as any thing in nature. This is called myotility or contractility. Wliutdo (lie lytiiplintics :iboim(l in? 74. Distiiifruisii bctAvocii tlio strii) 0 (l and tho misti iiKid imiHcuIar fiber. Clive the reason of the dillerence between a and l> in Fig. 23. Vo. Define luyctillty. AND rilYSIOLOGY. 27 Fia 24. Fig. 25. Fig. 26. 76. The Chemical Composition of Muscle. — The chem- ical composition of the muscular tissue is almost exactly the same as that of blood, as the following analysis will show : Blood. M little. Carbon 51.83 51.95 Hydrogen 7.6Y ’7.n Nitrogen 15.01 15.07 Oxygen 21.36 21.39 Ashes 4.23 4.52 100.00 100.00 76. State the chemical composition of muscle. 28 HITCHCOCK’S ANATOMY 7. Nervous Tissue. 77. Nervous Tissue; Tubular Cells. — This, like some of the other tissues, is composed of cells, fibers and tubes, but it is distinguished from all others by its vital endowments. In the ordinary nerve trunks the tissue is the fibrous or tubular, as is shown in fig. 27, A, B, and C. In C some of the original cel Is are shown. Fro. 27. 78. Vesi- cular Cells; Granular Cell s. — In those nervous masses called ganglia, w e find, in addi- tion to the fibers, a sub- stance made up of vesicles or cells, as is shown in the ganglion of a mouse on fig. 28. 77. How itj ncM-vous tissue to bo distinguished from all other tissues? 78. Describe the vesicular cells. AND PHYSIOLOGY. 29 Another primary element of the nervous system is com- posed of nucleated cells, containing a finely granulated sub- stance. These sometimes have processes which give them a caudate or stellate form, as in Fig. 29. Fia. 29. 79. All Organ. The System,— Such are the tissues which, combined in various proportions, make up the organs of the human body. And by the term organ we mean a part usually composed of several tissues adapted to certain functions. And though harmoniously united into a single system, that is, the body, the anatomist can dissect and describe them separately. In this work the following order wdll be adopted : 1. Osteology^ or an account of the Bones or framework of the system. 2. Myology^ an account of the Muscles or the moving pow- ers of the system. 3. SplayicJiTiology^ or the Nutritive Organs. 4. Angiology^ an account of the Circulating System of the arteries and veins. , Define an organ. What is the system ? What is Osteology ? Myology ? etc. 30 II I T C II C O O K ’ S AX A T O *M V 5. Pneumonologijj or an account of the Respiratory, Vocal, and Calorific Organs. 6. Ichorolofjy^ or the Lymphatic and Secreting System. 7. Neurology^ or the history of the Nervous System, the vivifying power. 8. The Inlets of the soul, or the Senses. 9. Religious teachings of the subject. CHAPTER FIRST. THE FRAMEWORK OF THE SYSTEM.— OSTEOLOGY, OR A DESCRIPTION OF THE BONES. DEFINITIONS AND DESCRIPTIONS. 80. Chemical Composition of Bone. — The Bones of all vertebrate animals are principally composed of the Phosphate and Carbonate of Lime, and, with the exception of the Teeth and articular extremities, are closely covered by a firm mem- brane called the Periosteum. By chemical analysis the com- position is as follows : Organic substance (Osteine or Cartilage) 33.00 Phosphate of Lime 57.00 Carbonate of Lime. 8.00 Fluorid of Calcium 1.00 Phosphate of Magnesia 1.00 100.00 81. Cartilage and Salts of lime shown. — Hence we see that the principal constituents of bone are the salts of Lime and Cartilage. The former can be easily obtained by burning the bone a while in a hot fire, which appears like a white powder when crushed. The Cartilage is obtained by im- mersing it for a considerable time in a dilute acid, when we have the form of the bone perfectly retained, although nothing is left but cartilage. Its elastic character may be inferred 80. What are the principal ingredients of bones? Where is the Periosteum found? Give the chemical analysis. 81. How can the earthy ingredients be shown? The car- 32 HITCHCOCK’S ANATO^FY frogi Fig. 30, Avliicli is a human Fibula tied in a knot after hav- ing been immersed for some time in muriatic acid. 82. Mechanical fonstnic- tion of Bones. — As a general law the extremities are the largest, and the bodies or shafts are smooth and of a uniform surface. They are in most cases so constructed as to give the greatest strength and sup- port, and at the same time fur- nish as little weight as possible. Hence the long bones are most- ly hollow, or have an arched form, while the flat bones are portions of a circle or sphere. In the face also the bones are not all solid, but some of them contain large cavities, so that firm attachment may be given to the muscles, and protection to the more delicate parts. 83. Average Weight of adult Skeleton.— The weight of the skeleton is as 10.5 : 100, or about one tenth the weight of the whole body. And since the average weight of an adult man is 136 pounds, the weight of an adult skeleton is about 13.5 pounds. 84. Strength of Bones. — The power of the human bones as levers when compared with different substances is remark- able, as is seen by the following table. Freestone (sandstone) 1. Lead 6.5 Elm and Ash (wood) 8.5 Box, Yew, and Oak 11. ^ Human Bone 22. Fig. 30. 82. Which part of the bones is penerally tlio largest? Why are many of the bones hollow or partially so? 88. Give the wclpht of the human skeleton. What is its pro- yortion to that of the whole body ? 84. Give the comparative strength of the bones. AND rilYSIOLOGY. 33 That is, bone when used as a lever is 22 times as strong as Sandstone, 3! times as strong as Lead, nearly 2f times as strong as Elm and Ash, and 2 times as strong as Box, Yew, and Oak timber. 85. Microscopic Structure of Bone. Haversian Canals. — Examined by the microscope the bones are found to be made up of plates or layers for the most part, arranged concentrically in the long bones, and in parallel layers in the flat ones. These are traversed in all directions, and espe- cially in their long diameters, by minute tubes or vessels called Ha- versian canals, which are also en- circled by several laminse or plates besides those following the general outline of the bone. Fig. 31. These canals have a diameter varying from T 2 V 0 24 ofh of an inch, while the accompanying lamellae show a thick- ness of ■co^^Trt'^ inch. They layer. 2 and 3 , inner layers, sometimes contain a capillary vessel, but more usually carry only the nutritive and watery portion of the blood. 8G. lacunsB, Canal iculi. — Besides these canals we find a smaller set of vessels or cells located directly in the substance of the concentric lamellae, called Lacunae or Bone Corpuscles, which average y oVo^h of an inch in length, and carry the fluid which nourishes the bone. These are of a black appearance, of an oval form, and with rays divergent in all directions, as Fig. 31. Transverse section of bone ■mofrnifia/-! 1 i «:» < sification, begins at Fig. 35. certain points, and continues until the whole is completed as is seen in the Fig. 36. In some of these bones there is but one of these centers, or points, where ossification commences, while in the Sphenoid there are 12. 97. Number of Bones. — The num- ber of bones in the human system is reckoned differently by different anatom- ists since many of the bones are well exhibited only in hard working or well developed mus- cular subjects. The number 246 will be given in this book as taken from Eras- mus Wilson, whose work on Anatomy is adopted as the text book in nearly all the medical schools of this country. This in- cludes the teeth, and sesamoid bones, of which the latter are not constant in every individual. They are summed up as follows : Section of cartilage near the point of ossification. 1, ordinary appearance of cartilage. 2 and 8, more ad- vanced stages of ossification. 1', 2' and 3' portiona 1, 2 and 3 more highly magnified. 97. What is the number of bones in the human body ? Give the different groups. 38 HITCHCOCK’S ANATOMY Fig. 3G. Fig. 37. A knee joint showing points of ossification, 1, 2 and 3. Head 8 Ear 6 Face 14 Teeth 32 Yertebrse, Sacrum and Coccyx. ... 26 Os Hyoides, Sternum and Ribs 26 Upper Extremities 64 Lower Extremities 62 Sesamoid Bones 8 246. 98. Vertebra;, Groups of Verte- bra, Cervical Vertebra;. — The Ver- tebrae or Spinal Column claim the first attention, since they are the Description of Fig. 37. view of tlic Si)inal Column. 1, Alla.s, 2, Axis (second Vertebra.) 3, Last Cervical Vertebra. 4, Last Dorsal V\*rtcbra. b, Last Lumbar. G and 7 Sacrum. 8, Coccyx. 9, a Spinous 1‘rocess, 10, Intervertebral Foramina. AND niYSIOLOGY SD Prontal Bone. PlGr. 38. Parietal Bone. Crbit. — — Lower Jaw. — Cervical Vertebras. Shoulder Blade. Humerus. * I^umbar Vertebrae. Carpus. Metacarpus. Tibia. Fibula. Temporal Bone. - Clavicle, Ilium. Patella. , Tarsus. Metatarsus. , Phalanges. 40 HITCHCOCK’S A N A T O 31 Y first developed bones, and the center around which the others are formed. They may be separated into the true and false : or those which are separable from, and movable upon each other, and those which are firmly joined together. Of the true vertebrae there are three sections, named in accordance with their location on the body : Cervical, Dorsal, and Lum- bar. The Cervical, or those of the neck, are seven in number, the first and second of which are the most remarkable. The first is named Atlas, from the mythological story that a giant of this name supported the earth on his shoulders, and it is Tig. 39. Fig. 40. The Atlas. 1, Anterior Tubercle. 2, Articular Face. 8, Posterior surface of Spinal Canal. 4, In- tervertebral Notch. 5, Transverse process. 6, Fo- ramen for Artery. 7, Superior oblique process. 8, Tubercle for transverse Ligament. sus (lentatus. 3, Articulating sur- face. 4, Foramen for vertebral Artery. 5, Spinous process. G aiul 7, Oblique processes. upon this one that the head is moved in a direction backwards and forwards. The second, called Axis, is characterized by a projection or pivot, which admits motion of the head in a horizontal direction, but in no other. It is the dislocation of this process, and the consequent pressure upon the spinal cord that causes death in criminals executed by hanging. 99. Dorsal Vertebra. — The Dorsal Vertebrae, or those of the back, are twelve in number, and give attachments to all the ribs. The central portion or body of each increases from above downwards, that they may more firmly support the superincumbent Avcight of the body. 98. Why arc the Vcrtcbric first described ? What two groups may tliey be divided into? W'hat other three sections of Vertebrse? What is the name of the first and second Vertebra? 97. How many Dorsal vertebra), and what boiios are attached to them ? AND PHYSIOLOGY. 41 Fig. 41. Fia 42. 5 A Dorsal Vertebra. 1, The Body. 2 and 7, Faces for head and tubercle of Rib. 3, Upper face of the body. 4 and 5, Interver- tebral Notch. 6, Spinous process. 8 and 9, Oblique processes. The Sacrum. 1 and 2, Articular sur- faces. 8, Promontory of the Sacrum. 4 and 10, Lines of former division of Sa- crum. 5 and 6, Foramina. 7, Sacro Iscliia- tic Notch. 8, Abe of the Sacj’iim. 9, Ob- lique processes. 100. lumbar Vertebrae. — The vertebrae of the Loins, or the Lumbar, are five in number, and are the largest members of the spinal column, since they are the only bones in this part of the body. They are more massive and solid in all their parts than the rest of this column, that they may be equal to the strength required of them. 101. Sacrum, — The Sacrum is a single bone, although its typical form is that of five vertebrae, which are actually found in some animals. Its appearance is that of five verte- brae, which are partially anchylosed or grown together. The form of the bone is somewhat like a wedge, with the base directed upwards, and the point curving inwards and for- wards. Fig. 43. 102. Coccyx, — The Coccyx is the lower extremity of the Spinal Column, formed of four anchylosed and imperfect verte- brae ; and it is an extension of these bones in the monkey which makes the tail. The Coccyx. 1, First bone. 2, 3, Processes to join the Sacrum. 4 and 5, Notches to form Foramen. 6, Last bone. 100. How many Lumbar Vertebrae? Why are they the largest in size ? 101. Describe the Sacrum. How many rudimentary vertebrae does it consist of? 102. Describe the Coccyx. 42 11 I T C II 0 O C K ’ S ANATOMY 103. General Remarks on the Spinal Column. — The Spinal Column viewed as a whole may be considered as made up of four cones, owing to the different sizes of the ver- tebrae. The apex of the upper one commences with the Atlas and extends as far as the first dorsal vertebra. Here the second one commences in an inverted position, extending over the upper three dorsal vertebrae. The third reaches with its base as far as the top of the Sacrum, where the inverted fourth one terminates with the Coccyx. Viewed from the front the spinal column should be in a straight line when in a healthy condition ; but a lateral view shows two curves, one at the lower part of the neck, and the other at the lumbar vertebrae, the design of this curvature being to place the head and its delicate contents upon an elastic and flexible support, and the design of the straight position in the other direction, being to give equal tension to the muscles on both sides. 104. Intervertebral Cartilage. — Between all the vertebrae is placed a thick cushion of cartilage. This by yielding not only allows a free and ready motion to the column as a whole, but is an additional protection to the brain, by diminishing the severity of any vibration communicated from below. 105. Bones of the Head. — The Skull may be considered as the superior expansion of the spinal column, Avhen it — the spinal column — is taken as the center of development of the whole body, which contains in the cranium the brain, and in the face most of the organs of sense. 106. In the Cranium or true skull are eight bones: 1 Frontal, 2 Temporal, 2 Parietal, 1 Occipital, 1 Sphenoid, 1 Ethmoid. 103. Of how many cones may the Spinal Column bo considered as composed? From what direction docs the Spinal Column appear in a straight line? Wliat curvatures does a lateral view show ? 104. What substance do we find between the vertebrae? Give Its use. 105. What may tho Skull bo consldorod as? What organs does it contain? lOG. Give tho bones of tho Skull. AND PHYSIOLOGY. 43 107. Frontal, T^iriporal, Parie- tn(, Occipital, Spdcnoid, and Eth- moid Bones. — The Frontal Bone is sit- uated in the upper and front part of the head, occupy- ing that portion of the skull called the forehead. It is mainly k flat bone, but the portion lying above the eye is hollow, in order that protection may be afforded to this delicate organ, as Avell as to give sufficient prominence to the up- per part of the face. The two Temporal Bones cover the front part of each side of the skull in that position com- monly known as the temples, and each bone is a little larger than the space which is pro- tected by the external ear. In the inner por- tions, called the petrous, are located the organs Fia. 44. 1, Frontal. 2, Parietal. 3, Occipital. 4, Temporal. 5, Nasal. 6, Malar. 7, Upper Jaw. 8, Lachrymal. 9, Mandible. Fig. 45. Frontal Bone. 1, Frontal Protuberance of right Bide. 2, Superciliary ridge. 8, Superorbitary ridge. 4 and 5, Angular processes. 107. What kind of a bone is the Frontal ? Why is a portion of it hollow ? W here are the Temporal Bones located? 44 HITCHCOCK’S anatomy of hearing. Directly behind the external car is felt a hard projection which is the mastoid process of this bone, and serves for the attachment of many muscles, which move the head. And directly in front of the ear is another prominent pro- cess, called the zygo- matic, which articulates with the malar bone, and to which is at- tached one of the ele- vator muscles of the ^jaw. The two Parie- tal Bones are eminently flat bones of a square shape, forming the es- sential parts of the pro- jections on the back sides of the head, and uniting with each other on the median line, up- on the top of the skull. They join with the frontal bone in front, the temporal bones below, and the occipital bone behind. The Occipital Bone has an imperfectly circular outline, and at its lower matic portion. 5, Articulating surface for lower jaw. 6, Temporal ridge. 7, Glenoid fissure. 8, Mastoid foramen. 9, Canal for ear. 10, Groove for digastric muscle. 11, Styloid process. 12, Va- ginal process. 18, Glenoid Foramen. 14, Groove for Eustachian tube. Fig. 47. Left Parietal Bone. 1, 2, 3, 4, Superior, Infe- rior, Anterior, and Posterior surfaces. 5, Ridge for Temporal Fascia. 6, Parietal Foramen. 7 and 8, Inferior angles. What is the mastoid process? Where is the zygomatic process ? Give the form of tlie Parictals. What is the outline of the Occipital Bone ? What is the large orifice in its lower part h»r? Give the position and general outline of the Sphenoid Bone. With what bones does this articulate? AND PHYSIOLOGY 45 edge a large orifice for the passage of the spinal mar- row, just as it enters the vertebrae. It is in the most posterior part of the skull, joining with the sphenoid in front, and rest- ing upon the Atlas verte- bra. The Sphenoid Bone is directly underneath the skull, extending from side to side, forming a very small portion of the out- side of the skull at the point \vhere the frontal and temporal bones come the nearest to each other. From its name we learn that it is somewhat wedge- Fig. 48. External surface of Occipital Bone. 1 and 4, Semicircular Eidges. 2, Occipital Protube- rance. 3, Attachment of ligamentum nuclaj. 5, Foramen for Medulla oblongata. 6, Condo le of right side. 7 and 8, Condyloid Foramina. 9, Jugular Eminence. 10, Jugular Foramen. 11, Basilar process. 12, Points of attachment for odontoid ligaments. 13, Edge for attach- ment with Parietal bone. 14, Point of attach- ment for Temporal bone. Fig. 49. The Anterior and Inferior Surface of the Sphenoid Bone. 1, 1, Apophyses of Ingras- sias. 2, 2, The great Wings. 3, Ethmoidal Spine. 4, Azygos Process. 5, Sphenoidal Cells, after the removal of the Pyramids of Wistar. G, Posterior Clinoid Processes. 7, Sphenoidal Fissure. 8, Foramen Rotundurn. 9, Depression for the Middle Lobes of the Cerebrum. 10, Surface for the Temporal Muscle. 11, Styloid Process. 12, Exter- nal Pterygoid Process. 13, Internal Pterygoid Process. 14, Pterygoid Foramen. 15, Ar- ticular Face for the Os Frontis. 16, Points to the Sella Turcica. 46 HITCHCOCK’S ANATOMY shaped in its general outline, although it is covered and filled with cavities and processes t for the protection and proper direction of many of the delicate organs which pass through it to their destination. This bone articulates with all those in the cranium, and five of those in the face, and serves as a point of attachment for twelve pairs of muscles, alnd is one of the most complicated bones belonging to the human skeleton. The last bone of the skull is situated at the base of Cribriform Plate. 5, Superior Meatus. A View of the Outside of the Vault of 6, Superior Turbinated Bone. 7, Middle the Cranium, showing the Sutures. 1, The Turbinated Bone. 8, Os Pb.nutn. 9, Sur- Coronal Suture. 2, The Sagittal Suture, face for the Olfactory Nerve. 3, The Lambdoidal Suture. the front portion of the cranium, between the sockets of the eyes, and behind the root of the nose. It is called the Ethmoid Bone. Its outline is that of a cube, consisting of a perpendicular plate, and two lateral portions. From the fact that it is extremely fragile, owing to the great number of perforations which it contains, it derives its name from the Greek word signifying a sieve. It is so deeply seated that it receives the attachments of no muscles. 108. S 111 n res. — The bones of the skull are united by Give tho shape and position of the Ethmoid bone. Why called Ethmoid? AND PHYSIOLOGY. 47 ragged edges called Sutures. These are small and rough projections of bone which are largest at their extremities. They are made to fit into the edges of the opposite bone with great firmness, thus joining the bones together, by essentially the same process which in cabinet work is known as dovetail- ing. The name Suture is applied, since when these edges are perfectly joined by this \articulation, they resemble the seam made by sewing together two pieces of cloth by the ‘^over and over’’ stitch. Situated directly within these sut- ures are frequently found small bones, uncertain as to number, sometimes two inches in diameter, called Ossa Tri- quetra. No special use for them has been discovered as yet. 109. The Lower Surface of the Skull.— The whole of the lower surface of the skull is extremely uneven for the attachment of a great number of muscles, and the protection of delicate nerves and blood- vessels which pass to and from the brain and face. 110. Bones in the Face. — The Face is that portion of the head situated below a line drawn from the orbit of the eye to the passage of the in- ternal ear. Its framework con- tains fourteen bones. 2 Nasal ; Fi&. 52. A Front View of che Skull, showing the Bones composing the Face. 1, Os Frontis. 2, Nasal Tuberosity. 3, Supra-Orbital Ridge. 4, Optic Foramen. 5, Sphenoidal Fissure. 6, Spheno-Maxillary Fissure. 7, Lachrymal Fossa, and commencement of the Nasal Duct. 8, Opening of the Anterior Nares, and the Vomer. 9, Infra-Orbital Foramen. 10, Ma- lar Bone. 11, Symphysis of the Lower Jaw. 12, Anterior Mental Foramen. 13, Ramr.s of the lower Jawbone. 14, Parietal Bone, 1,'\ Coronal Suture. 16, Temporal Bone. IT, Squamous Suture. 18, Great Wing of the Sphenoid. 19, Commencement of the Tem- poral Ridge. 20, Zygomatic Process. 21, Mas- toid Process. How -do the bones of the skull join with each other ? What process in cabinet making does it correspond to ? What are often found in these sutures? 109. AVhat is the sur- face of the lower part of the skull ? 110. Give the boundaries of the face. 3 48 II I T C ir c O C K ’ S A N ATOMY 2 Malar ; 2 Lachrymal ; 2 Superior Maxillary ; 2 Palate : 2 Turbinated ; 1 Inferior Maxillary ; 1 Vomer. 111. Nasal Bones . — The Nasal Bones are oblong, foursided bones, about an inch in length, which together form the bridge or base of the nose. Fia. 53. Fig. 54. An Anterior and Posterior View of tlie Nasal Bones. Right Hand Figure. 1, An- terior Inferior Extremity. 2, Articulating Surfixce for its Fellow. 3, Surface for the Nasal Process of the Superior Maxillary Bone. 4, Points to the Groove on the In- ner Side, for the Nasal Nerve. 5, Articu- lar Face for the Os Frontis. 6, Foramen for the Nutritious Artery . — Left Hand Figure. 1, Posterior Inferior Extremity. 2, Surface for its Fellow. 8, Surface for the Superior Maxilla. 4, Groove for the Internal Nasal Nerve. 5, Surface for the Os Frontis. 6, Lower portion of the Groove for the Nasal Nerve. 3 An Anterior Yiew of the Malar Bone of the Bight Side. 1, Anterior Oroital Angle. 2, Orbital Face. 3, Superior An- gle for articulating with the Os Frontis. 4, External An,le for the Zygoma of the Temporal Bone. 5 and 6, Inferior An- gle and Surface for the Superior Maxilla. 7, Nutritious Foramen. 112. Malar Bones. — The Malar Bones give the promi- nence and form to the cheek. They are partially hollow, of an irregularly quadrangular outline, and articulate with the frontal above, the zygomatic process of the temporal behind, and the superior maxillary below. The name is from the Latin Ma/a, a cheek/’ hence cheek bones. 113. Ijaclirymal Bones. — The Lachrymal Bones are the IIow many hones in tlio Face, and what aro their names ? 111. Describe the Nasal Bones. 1 12. WJiat bones aro found in the cheeks ? AND PHYSIOLOGY. 49 smallest bones in the Face, being about |th of an inch in diameter. They are situated at the inner angle of the eye, and are named from the Latin Lachryma^ a tear/’ since the tears pass into the nostrils through a canal in these bones. This bone is also called Os Unguis. Fig. 56. An Anterior View of the Os Un- guis of the Left Side. 1, Its An- terior Inferior Angle. * 2, Orbitar Plate and Side for the Os Pla- num. 3, Fossa for the Lachry- mal Sac. 4, Superior Extremity. A Posterior and Half Lateral View of the Pal- ate Bone, 1, Palate Plate on its Nasal Surface. 2, Nasal Plate. 3, Pterygoid Process. 4, Sur- face for Articulating with its fellow. 5, Half of the Crescentic Edge and Spine for the Azygos Uvuhe Muscle. 6, Bidge for the Inferior Spongy Bone. 7, Spheno-Palatinc Foramen. 8, Orbital Plate. 9, Pterygoid Apophysis. 10, Depression for the External Pterygoid Process of the Sphenoid Bone. 11, Same for the Internal Pterygoid Process, 114. Palate Bones, — The Palate Bones are the most ir- regular bones of the face, and resemble the capital letter L. of the eye, the wall of the nose, and a large part of the roof of the mouth which is known as the hard palate. 115. Turbinal Bones. — The Turbinal Bones (really the Inferior Turbinated Bones, since corresponding plates upon the ethmoid bone are called Superior Turbinated when viewed in one direction They form a part of the orbit Fig. 51. 4 An External View of the Inferior Spongy Bone of the Right Side. 1, An- terior Extremity, for resting on the Ridge of the Upper Maxilla, 2, Posterior for resting on the Ridge of the Palate Bone. 3, Hooked portion, for resting on the Lower Margin of the Antrum High- morianum. 4, Its Inferior Border. 113. What arc the smallest bones of the face, and why called Lachrymal ? 114. "What are the most irregularly-shaped bones in the face, and what portion of the mouth is made up by the Palate Bones? 115. Give the description of the Turbinal Bones. 5) II I T C II C O O K ’ S ANATOMY Bones') are curved laminye or thin ])latc3 of bone, resembling a loose scroll, and are found in each nostril, for the j)ur|) 03 e of affording as large a surface as possible for the expansion of the mucous membrane of the nose, which contains the nerves of smell. The name Turbinal or Turbinated is ap- l)]ied because of their scroll-like appearance. 116. Siippi’ior Jinx illary Bone.— The Superior Maxilla- ries are the largest bones of the face, joining with each other An External View of the Superior Max- The Inferior Maxillary Bone. 1, Tho ilia of the Left Side. 1, Orbitar Process. Body. 2, The Ramus. 3, The Syniphy- 2, Infra-Orbitar Canal. 3, Space for the sis. 4, Alveolar Process. 6, Anterior Os Unguis. 4, Upper part of the Lachry- Mental Foramen. 6, The Base.' 7, inal Canal. 5, Nasal Process, and Sur- Groove for the Facial Artery. 8, Tho face for Articulating with the Os Frontis. Angle. 9, Extremity of the Ridge for G, Surface for the Nasal Bone. 7, Anterior the Mylo-IIyoid Muscle. 10, Coronoid portion of the Floor of the Nostril. 8, Sur- Process. 11, Condyle. 12, Neck of tho face for Articulating Avith its Fellow. 9, Al- Condyloid Process. 13, Posterior Men- A'oolar Process. 10, Points to the Depression tal Foramen. 14, Groove for the Infe- just below the Infra-Orbitar Foramen. 11, rior Maxillary Nerve. 15, Molar Teeth. Surface for the Malar Bone. 16, Bicuspidate Teeth. 17, 13, Middle and Lateral Incisors. on the median line, and thus form a portion of the roof of the mouth. Each one of them articulates with eight teeth, with all the bones of the face but the lower jaw, and two of the cranium. Their name is from the Latin, Maxilla^ a jaw/’ and both of them constitute the upper jaw. 117. Miilidiblc. — The Inferior Maxillary, or lower jaw, is 11G. How arc tlio Superior Maxillaricis situated ? How many teeth arc found in each ortliemV 117. Describe tho Mandible. AND PHYSIOLOGY. 51 the only movable bone of the head or face. It contains the sixteen lower teeth, is of an arched form, and at each ex- tremity has a square-shaped process for articulation with the temporal bones, and the attachment of muscles. 118. Vomer. — The name of the Vomer is derived from the Latin meaning a “plow- share,” on account of its approximate resem- blance to that object. It completely separates the nostrils from each other, and like the tur- binated bones gives at- tachment to no mus- cles. Fig. 60. The Vomer. 1, 2, Posterior and Superior Surface hollowed to receive the Azygos Process of tho Sphenoid Bone. 3, Anterior Surface for the Car. tilaginous Septum of the Nose. 119. Number of Teeth. — The Teeth of the Human Adult when all present in the jaws, number thirty-two. And al- though properly bones, still they differ in three respects : 1st, Organic Composition. 2nd, Time of Development and Replacement. 3d, Decay when fractured. 120. Organic Composition, Cementum, Dentine, Enamel, Microscopic Structure of Enamel, Development of Teeth, Nasmyth’s Membrane.— The Teeth are composed of three substances : a Cementum which forms a thin coating on the fangs of the teeth, and which thickens in advanced life ; the Dentine which resembles bone in its external characteristics and makes the largest part of the teeth, containing the prin- cipal vessels and nerves of the teeth ; and the Enamel, the hardest substance in the human body, which is a covering to IIS. From w’h at does the Vomer derive its uamc? What two cavities does it sep- arate ? 119, IIow many teeth in an adult? In what respects do they differ from the other bones of the body? 120. Of what substances are tho teeth composed? 52 HITCHCOCK’S A N A T O INI Y Fig. 61. ■Vertical Section of Human Incisor, the point where the Gum is attached the Tooth. Fig. 63. Fig. 64. A View of an Incisor and of a Molar Tooth, given by a Longitudinal Section, and showing that the Lnaihcl is striated and that the Strim are all turned to tho center. Tho Internal Structiiro Is also sc(m. 1, Tho Enamel, 2, The Ivory. 8, Tho Cuvitas Pulpi. Fig. 62. A Vertical Section of an Adult Bicuspid, cut from without inwards; magnified four times. 1, 1, The Cementuin which sur- rounds the Root up to the commencement of the Enamel. 2, 2, The Dentine of the Tooth, in which are seen the greater Parallel Curvatures, as well as the position a, of the Main Tubes. 3, Apex of the Tooth, to where the Tubes are almost perpendicular. 4, 4, The Enamel. 5, The Cavity of tho in which are seen, by means of the Glass^ Openings of the Tubes of the Dental Bone. all the tooth above the gums. This is a pure -white sub- stance, thickest upofl the top of the crown, and gradually growing thinner towards the gum, where it disappears al- together. Under the micro- scope it is seen to be made up of minute hexagonal fibers, one end of which rests upon the Dentine, and the other forms the free surface of the tooth. These tubes or fibres arc slightly undulating and AND PHYSIOLOGY 53 from 8 oVoth to 54 V 3 d of an inch in diameter. The en- amel is also covered by a very thin membrane, rjbs ist of an inch in diameter, called Nas- myth’s membrane. This is a calcified” membrane and can be seen only with great care, since it is not acted up- on by the strongest acids or alkalies. 121. Development of Tectli. Temporary Set. Permanent Set. — The teeth in the human subject are not perfectly formed at birth, but exist in the form of follicles or shut sacs, which at the seventh or eighth month of infantile life, are developed into teeth. The process of dentition generally occupies from one to three years, during which time the temporary set, as it is termed, make their appearance. These number twenty, ten in each jaw, and between the age of seven and fourteen become loose, and are easily removed to give place to the per- manent set which numbers thirty-two. Generally, however, the last tooth in each jaw does not make its appearance until the twentieth year of life. 122. A more accurate statement of dentition of the tempo- rary teeth shows that they a'lrpear at the following ages : The Incisors, from the Ith to the 10th rnonth. The Anterior Molars, 12th “ 13th 11 The Canine Teeth, 14th ‘‘ 20 th n Posterior Molars, 18th “ 36th , u Fig. 65. A portion of the Surface of the Enamel on which the Hexagonal Terminations of the Fibres are shown ; highly magnified. 1 2, 3, Are more strongly marked dark, crooked Crevices, running between the rows of the Hexagonal Fibres. 123. The permanent teeth appear as follows : Describe each of the teeth. What membrane completely covers the outside of the tooth? 121. Illustrate the development of the teeth. 122. Give the time of appearance of the temporary teeth. 123. When do the permanent teeth appear ? 54 TI I T C TI C OCR’s A N A T O M Y I Incisors, from tlio 8tl> to tho 9th year. Bicuspids, 10th “ 11th “ Canines, 12tli “ 12Jth “ Second Molars, 12JtIi “ 14th “ Third Molars, 17th “ 19th “ 124. Names of Teeth. — A third set of teeth has been known to make its appearance ; also a tooth extracted and at once replaced may become firm again at the end of some months. The names and number of the permanent teeth in each jaw, beginning at the posterior part of the mouth, are : 2 Wisdom, 4 Molars, 4 Bicuspids, 2 Canine, 4 Incisors. Fig. 6G. a, 1)^ Incisoi«. c, Canine, d, Bicuspids. /, Molars. A Wisdom teeth. 125. Fracture of Teeth. — All the bones of the body, ex- cept the teeth, when broken will become united again ; but if the teeth lose a portion of their enamel, or even if it be cracked, the tooth so injured at once begins to dec^ay, and will be entirely consumed, unless the disease be checked by artificial means. 124. What i.s said about a third set? Give tho names of tho permanent teeth. 125. What it tho teeth aro lirokcn or cracked ? AND PHYSIOLOGY. 55 126. Hyoid Bone. — The Hyoid Bone is the bone which forms the base of the tongue, and the upper extremity of the trachea. It has the shape of the Greek letter U (or Upsilon) and articulates with no other bones, but is completely enveloped by the soft parts. It has a consi- derable range of motion in a vertical direction, and hence gives attachment to no less than eleven pairs of muscles. 127. Sternum. — The Breast Bone is flat, about eight inches in length, one and a half in width, and is located on the median line of the body upon the front portion of the tho- rax or chest, articulating with the seven upper ribs on both sides, and also with the clavicle. 128. Ribs. — There are twenty-four ribs in the human Fig. 69. 3 A View of the Upper Side of the First Kib of the Right Side, half the size of na- ture. 1, The Head. 2, The Tubercle. 8, Anterior Surface. 4, Groove for the Sub- clavian Artery. 5, Groove for the Sub- clavian Vein. 6, Anterior Extremity for A Front View of the Sternum. 1, First the Cartilage. 7, Tubercle for the Scalenus Piece. 2, Second Piece. 3, Ensiform Car- Anticus Muscle, tilage, or Third Piece. 4, Articular Face for the Clavicle. 5, Articular Face for the First Rib. 6, Articular Face for the Second Rib. 7, 8, 9, 10, Articular Faces for the Last Five True Ribs. 126. Where is the Hyoid Bone? What Greek letter does it resemble ? 127. Describe the Sternum. With what bones does it articulate ? 128. Number of Ribs in man? 3 * Fig. 67. An Anterior View of the Os Hyoides, 1, The Anterior Convex Side or the Body. 2, The Cornu Majus of the Left Side. 3, The Cornu Minus of the same Side. The Cornua were ossified to the Body of the Bone, in this specimen. HITCHCOCK’S ANATOMY 5G Tia. ^0. General Character of the other Ribs, seen on their Upper and Under Surface. The left hand figure is the Upper Face of the Rib. 1, Head of the Rib. 2, Its Tubercle. 3, Anterior Extremity for the attachment of the Costal Cartilage. 4, Groove for the Ar- tery and Nerve. 5, Angle of the Rib. The right hand figure is the Under Surface of the Rib. 1, The Head. 2, Its Tubercle. 8, Anterior Extremity. 4, Groove for Inter- costal Artery and Nerve. 5, Angle of the Rib. body, which are divided into two classes, the true and the false, or those which are closely united with the sternum, and those which are remotely attached to it by long cartilages. They are attached at their posterior extremities to the verte- brae, and run downwards and forwards, so that when elevated, Fig. 11. Vertebral Column. Ribs. AND PHYSIOLOGY. 57 they enlarge the cavity of the chest. The true ribs are the seven uppermost ones, and the false the five lower ones, and are so arranged that they form a cone with the apex at the neck. The two lowest ribs are sometimes called ^^floatino- because they are only attached to the vertebrae. 129. Clavicle. — The Collar Bone is the 2. commencement o f the upper extremity. It is one of the class of long bones ex- tending from the Anterior View of the Claviele of the Right highest point of the side, l, The Anterior Faec of the Body of the Bone. , 2, Origin of the Clavicular portion of the Stcrno- SCapula to the upper Cleido-Mastoid Muscle. 8, The Sternal Extremity of Dart of the sternum Bone. 4, The Acromial Extremity of the Bone. ^ 5, Articular Face for the Acromion Process of the Scapu- and bears a partial la. 6, Point of Attachment of the Conoid Ligament, resemblance to the Point of Attachment of fhe Rhomboid Ligament. Italic letter F. The name is from the Latin Clavis^ *^a key/’ since it remotely resembles an antique key. 130. Scapula. — A large, flat, and triangular bone upon the upper part of the back, and forming the shoulder, is called the Scapula, or Shoulder Blade. It has a high and narrow ridge running through its longest diameter, which is the bone so distinctly felt upon the shoulder and upper part of the back. Its only articulations are with the clavicle and humerus, the posterior part being kept in its place by mus- cles and ligaments. (Fig. 73, p. 58). 131. Humerus. — The Humerus is the bone of the upper arm or shoulder. (Fig. 74, p. 58.) It is a long bone with a cylindrical shaft, and has a rounded head for its upper ex- tremity. The lower extremity is flattened from before back- What two classes are they divided into? What do they all unite with behind? 129. What two bones does the Clavicle unite with ? 180. What is the general outline of the Scapula? Where is it located? What are its only articulations ? 131. What is the bone of the upper arm ? 58 II I TO IT COCK’S ANATOMY Fio. 13 . Ym. 1i. A Posterior View ot the Scapula of the Left Side. 1, Fossa Supra-Spinata. 2, Fos- sa Infra-Spinata. 8, Superior Margin. 4, Coracoid Notch. 5, Inferior Margin. 6, Glenoid Cavity. 7, Inferior Angle. 8, The Neck and Point of Origin of the Long Head of the Triceps Muscle. 9, Posterior, or Vertebral Margin. 10, The Spine. 11, Smooth Facet for the Trapezius Muscle. 12, Acromion Process. 13, Nutritious Fo- ramen. 14, Coracoid Process. 15, Part of the Origin of the Deltoid Muscle. An Anterior View of the Humerus of the Eight Side. 1, The Shaft, or Diaphysis of the Bone. 2, The Head. 3, Anatomical Neck. 4, Greater Tuberosity. 5, Lesser Tubero.sity. 6, The Bicipital Groove. 7, External Bicipital Eidge for the insertion of the Pectoralis Major. 8, Internal Bici- pital Eidge. 9, Point of insertion of the Deltoid Muscle. 10, Nutritious Foramen. 11, Articular Face for the Head of the Eadius. 12, Articular Face for the Ulna. 13, External Condyle. 14, Internal Condyle. 15, 16, The Condyloid Kidges. 17, Lesser Sigmoid Cavity. wards, and so formed into grooves and elevations that it ar- ticulates with the ulna in essentially the same manner as the two portions of a door hinge. 132. Fore-arm. Tlie Ulna. — There are two bones in the forearm, one of which only is articulated with the humerus, and the other to the bones of the wrist alone, in order to al- low the rotation of the hand upon the bones of the forearm, Wliat i.i the shape of the lower, or ulnar articulation? 182. How many bones in the foreanri ? Why are there two instead of one ? AND PHYSIOLOGY. 59 as if they constituted a pivot ; an instance of which is seen in the turning of a screw, or in the unlocking of a door. Of these two boaes the Ulna arti- culates with the humerus, form- ing only a ligamentous union with the bones of the wrist. It is prismoid in form, and is of a hooked shape at its up- per extremity, so that it makes the union between it- self and the humerus a very secure one. The word ulna is a Latin term signifying an ell, because the forearm in early times was used for that measure. 133. The Radius. — The Radius is the mate of the ulna. Its upper extremity is the smallest, and the lower the largest, since its only true articulation is at the wrist. A firm membrane, however, unites this bone to its fellow nearly its whole length. It prob- ably derives its name from the fact that it measures the ra- dius of a circle which may be described by the hand about the elbow as a center. Bones of the Forearm. 1, The Ulna. 2 and 3, The Sigmoid Notches. 4, The Olecranon Process. 5, Coronoid Process. 6, Nutritious Foramen. 7. Ridge for at- tachment of Interosseous Membrane. 8, Capitulum Ulnje. 9, Styloid Process. 10, Shaft of the Radius. 11, 12 and 13, Head, Neck, and Tuberosity of Radius. 14, Ob- lique Line for muscular attachments. 15, Styloid Process. 134. The Carpus. — The bones of the Carpus or Wrist are eight in number, are small and . irregular, and have the gen- eral disposition of two rows. The first row, commencing with the one nearest the thumb, contains the Scaphoid, Semilunar, In what operations do we need the two bones of the forearm ? Give the derivation of ulna. 133. What is the mate of the ulna? Where does this articulate? What is the derivation of its name ? 184. How many bones in the wrist? Give their names. CO II T T G II G O G IC ’ S A N- A T O ]M Y Fig. 7G. A Posterior Yiew of the Articulations of the Bones of the Carpus in the Bight Hand, 1, The Ulna. 2, The Badius. 3, Inter-Articular Fibro-Cartilage. 4, Meta- carpal Bone of the Thumb. 5, Metacarpal Bone of the First Finger. C, Metacarpal Bone of the Second Finger. 7, Metacar- pal Bone of the Third Finger. 8, Meta- carpal Bone of the Fourth Finger. S, The Scaphoides. L, The Lunare. C, The Cu- neiforme. P, The Pisiforme. T, T, Tra- pezium and Trapezoides. M, The Mag- num. U, The Unciforme. Fig. V7. An Anterior View of the Left Hand. 1, The Scaphoides. 2, The Lunare. 3, The Cuneiforine. 4, The Pisiforme. 5, The Trapezium. 6, Groove for the Flexor Carpi Badialis Tendon. 7, The Trape- zoides. 8, The Magnum. 9, The Unci- forme. 10, 10, The Five Meta-Carpal Bones. 11, 11, First Bow of Phalanges. 12, 12, Second Bow of Phalanges. 13, 13, Third Bow of Phalanges. 14. First Pha- lanx of the Thumb. 15, Last Phalanx of the Thumb. Cuneiform, and Pisiform. The second in the same order, the Trapezium, Trapezoid, Magnum, and Unciform. 135. The Metacarpus. — The Metacarpus contains five bones. Each of these articulate with the carpus above, and the phalanges below, being found in the space known as the palm or body of the hand. 186. The Phalanges. — The Phalanges are tlie bones of the thumb and fingers, two in the former, and three in the latter, making fourteen in each hand. 135. Describe tlio Metacarpal Bones. What part of the hand do they occupy? 130, How many Plialangos in the thumb, and how many in each finger? What is the whole number of them? AND P II S I O L O G Y . Cl 137. Bones of the Pelvis. — The bones of the Pelvis are the two Innominata or nameless bones, and the Sacrum and Coccyx, which have already been described. (Fig. 78 .) Fig. 78. 138. The Iniiominatuin, Ilium, Ischium, Puhes, — Each Innominatum presents the largest surface of any bone in the body. They are irregularly flat bones and situated just beneath the abdomen, to the organs of which they give firm support by their broadly-expanded surface. In young skele- tons they are divided into three portions, and hence they are described in the adult as made up of three parts, although no line of division can actually be seen. The Ilium constitutes the broadly-expanded portion usually known as the hip or haunch. The Ischium, from the Greek signifying to hold’^ or ‘'retain,’’ is the heavy portion projecting downwards, and that point on which the body rests, when in a sitting posture. 137. IIow many bones in the Pelvis, and what are their names? 138. Describe the Innominatum. Into how many parts are they divided in young animals? Describe the Ilium and the Ischium. G2 IT I T c ir c O C K ’ S A N A T o :\r \ Fig. 10 . Outside of the Innominatiim of the Right Side. 1, Dorsum of the Ilium. 2, Ischium. 3, Pubis. 4, Crest of the Ilium. 5, Surface of the Gluteus Medius. 6, Surface for the Gluteus Minimus. 7, Surface for the Gluteus Maximus. 8, Anterior Superior Spinous Process. 9, Anterior Inferior Spinous Process. 10, Posterior Superior Spin- ous Process. It, Posterior Inferior Spinous Process. 12, Spine of the Ischium. 13, Greater Sacro-Sciatic Notch. 14, Lesser Sacro-Sciatic Notch. 15, Tuber Ischii. 16, Ascending Ramus of the Ischium. 17, Body of the Pubis. 18, Ra- mus of the Pubis. 19, Acetabulum. 20, Thyroid Foramen. An Anterior View of the Femur o the Right Side. 1, Depression f<;r the Round Ligament. 2, The Head. 3, The Neck. 4, Trochanter Major. 5, Trochanter Minor. 6, Surface for the Capsular Ligament. 7, Shaft of the Bone. 8, The External Condyle. 9, The Internal Condyle. 10, Surface for the Patella. The Pubis is the most central and anterior portion. These three divisions unite at the point known as the acetabulum or receptacle for the head of the femur, which is a perfect hemi- spherical cup lined with cartilage. 139. Tlie Femur. — The Femur is nearly two feet in length, and consequently the longest bone in the body, commonly known as the Thigli Bone. At its upper portion it makes a 189. What is tlio average length of the Femur? Give its general features. What ii the longest bone in the bo'dy ? ' A PHYSIOLOGY. G3 sudden bend inwards, forming the neck of the bone, the ter- mination of which is hemispherical, in order to articulate with the innominatum, forming the ball and socket joint. Its lower extremity has two large condyles or processes, for the purpose of giving attachments to the ligaments of the knee, and articulating with the tibia. 140. The Patella — Or Knee Pan is the si. largest sesamoid bone in the body. It arti- culates with the femur, and lies imbedded in the extensor tendon of the thigh. The chief value of this bone is to give a change of direction to the force of the muscles which move the lower bones of this extremity we are now describing. Patella in Latin signi- AnteLrTicvv of fies a plate, and hence the name of this tiiePateiia. i, 2 , sm- _ , TIT face for the Quadriceps bone, because ot its rounded outline. Femoris Tendon. 3 , Lower Extremity and 141. The Tibia. — That portion of the Point of Oriitin of the , *,11 11 1 • 1 • LigaTnentiim Patellai. lower extremity below the knee, which is properly the leg, has two bones called crural for its frame- work. The largest of these is the Tibia (Fig. 82, p. 64.) It is somewhat triangular in its general outline, having its upper extremity depressed in two places for the reception of the condyles of the femur. Besides the femur above, it articulates with the fibula and astragalus below. The name tibia is given to the bone, since it resembles, though remotely, the ancient Phrygian flute. 142. The Fibula. — The Fibula is the other bone of the leg, long and slender. It articulates at each end with the tibia. The meaning of the Latin fibula^ is a ^^pin,’’ or fastening of a clasp, owing to its slender form. The lower extremity of this bone, and also that of the tibia, forms what 140. Describe the Patella or Knee Pan. In what is it imbedded? 141. What is the Leg? What are the two bones of it? Which is the largest and consequently most im- portant one ? 142. Give the general description of the Fibula. What compose the ex- ternal and internal Malleoli ? G4 II I T C IT O O C K ’ S ANA r O M V Fig. 82. Fig. 8?>. Eight Tibia and Fibula. 1, Tibia. 2 Avith the Naviculare. 3, The Os Cub-is. and 3, Inner and Outer Tuberosity. 4, 4, Naviculare, or Scai)hoides. 5, The In- Spinous Process. 5, Tubercle for attach- ternal Cuneiform. 6, Tlie Middle Cunei- inent of Muscles of the Thigh. 6, Edge of form. 7, The External Cuneiform. 8, Tibia. 8, Internal Ancle. 9, The Fibula. The Cuboid Bone. 9, 9, Metatarsal Bones. 10 and 11, Extremities of Fibula. 10, First Phalanx of the Big Toe. 11, Sec- ond Phalanx of the Big Toe. 12, 12, 13, 13, 14, 14, The First, Second and Third Phalanges of the other Toes. arc known as the external and internal malleolus, or the two long projections on each side of the ancle. 143. The Tarsus. — The Tarsus is made up of seven ir- regular bones, forming the instep of the foot. The Astra- galus is of a cubical form (so named from its resemblance to the die, used in games of chance) and supports the tibia alone. The Os Calcis, meaning tlic bone of the heel, is the largest of the bones of the tarsus, and is irregularly cubical 143. TIow many bones rnako up the Tarsus? Why is the uppermost called the Astra- galus ? Which is the largest of these bones? AND PHYSIOLOGY. C5 in form, making, by a decided projection, the heel. Directly beneath and anterior to the last two, are found the Cuboid (cube-shaped) and the Scaphoid (boat-shaped), and anterior to these the three Cuneiform (wedge-shaped), articulating with the metatarsal bones in front. 144. Metatarsal Bones. — These are five in number, and correspond with those in the metacarpus, except that the one in the first toe is of equal length with the others, and does not admit of so free motion as that of the thumb. 145. The Phalanges. — The Phalanges of the foot are also like those of the hand, except that in the foot the first row is the longest, while in the hand it is in the third row or second finger. 146. Sesamoid Bones. — Besides the bones already men- tioned, there are frequently found in stout adult men small bones, or portions of bony matter called Sesamoid Bones, from their resemblance to the Sesamum, a kind of bean. And although they are not constant either in individuals, or in the same places in the individual, yet anatomists are accustomed to reckon eight, or four pairs as the normal number. They are all found enclosed in tendons, and serve like the patella to change the direction of motion. They are found at the point where the tendon glides over the joint made by the phalanges and metatarsus of the foot, and the metacarpus of the hand, in the tendon which plays over the under surface of the cuboid bone in the foot ; and also in the tendons that glide over the lower condyles of the femur. 147. Bones of the Ear. — In the Ear are three bones which will be more appropriately described with the organ itself. 148. Number of Bones. Single Bones.— Of the 246 144. How many Metatarsal Bones ? 145. How many Phalanges of the Foot? How do they differ from those of the hand ? 146. Describe Sesamoid Bones. How many are there, and where are they generally found ? 147. How many hones of the Ear ? CG IT I T C II C O C K ’ S ANATOMY bones found in the human body, all but thirty-four are found in pairs, or one upon each side of the body. The single bones are the frontal, occipital, ethmoid, sphenoid, vomer, mandible, hyoid, sternum, twenty-four vertebrae, the sa- crum and the coccyx. SYNDESMOLOGY. DESCRIPTION OP THE LIGAMENTS. 149. Kinds of Articiilntion. — The modes or manner of connection between the different bones of the body are three : Synarthrosis, Amphiarthrosis, and Diarthrosis. The first of these modes, means the joining of such bones as have no motion between them ; the second, a joint with the aptitude for movement between the immovable synarthrosis on the one hand, and the movable diarthrosis on the other ; the third, a movable articulation, which constitutes by far the greater part of the joints of the body. 150. Sutura, llarmonia, Schindylesis, Gompliosis. — Of Synarthrosis there are four varieties : first, Sutura, the ar- ticulation between the bones of the skull by ragged inter- locking edges ; second, Harmonia, that between the two upper maxillaries, where the bones with comparatively straight edges are simply placed edge to edge ; third, Schindylesis, or the joint between the vomer and sphenoid, where the ex- panded edge of one bone is fitted into a corresponding groove in the other ; fourth, Gompliosis, the articulation of the teeth with the jaws, and so named since it resembles the manner in which a common nail is driven into a plank. 118. How many bones in tlio buman body are found in pairs? Give the names of the nnrnated bones. 140. How many modes of connecting the bones together? Describe each. 150. Give t)ie peculiarities of Sutura, of Harmonia, of Schindylesis, and of Gom- phosis. Give an example of the latter. AND PHYSIOLOGY. 67 151. Symphyses. — Of Amphiarthrosis there is but one hind, the Symphyses, or the apposition of two bones with simply cartilage between. Examples of this are the arti- culations of the vertebrae, and the ossa pubis. 152. Arthrodia, Giaslymus, Eiiartlirosis. — Of Diarthro- sis there are three v: rieties : Arthrodia, Ginglymus, and En- arthrosis. Arthrodia is a slightly movable joint, as of the wrist and ancle bones, or the radius and ulna. Ginglymus is the common hinge joint, where the degree of movement is very considerable, but only in two directions. The best example of this is in the knee. Enarthrosis is the ball and socket joint, that admits of movement in all directions. The only cases of this articulation are in the shoulder, hip, and thumb. 153. Anatomy of the Articulations. — In synarthrosis there is simply a membrane interposed between the two bones which keeps them in their places. In amphiarthrosis the two extremities are partly covered with cartilage, lined by synovial membrane, and partly connected by the interosseous ligaments, or by an elastic fibro-cartilage which adheres to both edges of the bones. In diarthrosis especially, as it is exhibited in ginglymus, the general outline of the bone is quadrilateral, upon each edge of which is found a ligament. The lateral ones, however, are the main supports of the joint, while the anterior and posterior ones are thin and a part of the time loose, which are only of service to determine the amount of movement in the joint. An example of this is seen in the fingers, since they can only be extended so as to lie in the axis of the metacarpal bones. The reason why they can not be bent back upon the dorsal surface o? the hand is that the anterior ligament does not admit of sufii- 151. Describe the Symphyses. Give an example, 152. Give the three varieties of Diar- throsis. Give an example of Arthrodia, Ginglymus, and Enarthrosis. 153. What are the component parts of the different articulations? Give the mode of articulation of the fingers. Why can not the finger bo bent upon the back of the hand? G8 HITCHCOCK’S A K A T O .AI Y cient movement in that direction. In the knee, liowevcr, there are thirteen ligaments. 154. Motions of the Joints. — The motions of the joints may be comprised under four principal divisions : Gliding, Angular movement, Circumduction, and Rotation. 155. Gliding. — Gliding movement is where the bones simply slip over one another in the movement of the joint, and exists to a greater or less extent in all the joints. 156. Angular. — Angular movement may be performed in four directions : forwards and backwards, called flexion and extension, and inwards and outwards, called adduction and abduction. A joint, as the finger, is said to be flexed Avhen it is bent upon itself, that is upon the palm of the hand, and extended when it is stretched to its fullest extent, or as in the finger, when it is made straight with the bones of the fore-arm. Adduction means the bringing of one of the extremities towards the body, or its fellow, while abduction has the reverse signification. 157. Circumduction. — Circumduction can be performed only by the ball and socket joints. It consists in carrying the limb about the joint in a circular plane, or in other words, describing a circle about the joint as a center. 158. Rotation. — Rotation is the movement of a bone upon its own axis. A slight rotatory movement can be efiected in the joints of the shoulder and hip, but the best instance is that of the radius rotating against the articular head of the humerus, producing the subdivisions pronation and supina- tion. Pronation consists in rotating the fore-arm so that the palm of the hand shall bo downwards, and Supination the reverse. Rotation is also observed in the movement of the atlas upon the pivot of the axis. Whjit an* tlio four itiotions of tlio joints ? in.*). Describe the Gliding movement, l.nf). In wlmt f<»nr directions can Angular movements bo? I.IT. What is Circumduction? 1.53. Describe notation. What is Ib-onation and Supination? AND PHYSIOLOGY 69 159. Structure of liigaments. Ar- rangement of Liga- ments. Capsular ligament. Round Ligam ent. — The bones are firmly bound together by ligaments. These are for the most part bands of white glistening fibres, as firm as steel, which are composed of white fibrous tis- sue. They are gen- erally very short, and attached only to the enlarged ex- tremities of the bone. In most of the joints, and es- pecially the gingly- mus, the ligaments are arranged in a cross shape upon the sides of the bones, so that one bone may glide freely over the extremity of an- other, as one half of a door hinge moves upon its other half In other in- stances the ligament surrounds the w^hole Fia. 84. A magnified View of a Vertical section of Cartilago from a new-born Rabbit, showing the progress towards ossification. 1, The Ordinary appearance of Tempo- rary Cartilage. 1', The same, more highly magnified. 2, The Primary Cells beginning to assume the linear direction. 2', The same, more highly magnified. 3» The Ossification is extending in the intercellular spaces, and the rows of cells are seen resting in the cavities so formed, the Nuclei being more separ- ated than above. S', The same, magnified more highly. TO HITCHCOCK’S ANATOMY Fig. 85. An Anterior View of tbo Ligaments of the Pelvis. 1, The Lower part of the An- terior Vertebral Ligament 2, The Sacro- Vertebral Ligament. 3, The Ilio-Lumbar Ligament. 4, The Anterior portion of the Sacro-Iliac Ligament 5, The Obturator Ligament 6, Poupart’s Ligament. 7, That portion of the same which is known as Gimbernat’s Ligament. 8, The Capsular Ligament of the Ilip-Joint 9, The Ac- cessory Ligament of the Hip-Joint Fig. 8G. Ligaments from Shoulder-Joint. 1, The Superior Acromio-Clavicular Ligament. 2, The Coraco-Clavicular Ligament 3, The Coraco- Acromial Ligament 4, The Coracoid Ligament. 5, The Capsular Liga- ment of the Shoulder-Joint 6, The Liga- mentum Adscititium, or Coraco-IIumeral Ligament. 7, The Tendon of the Long Head of the Biceps Muscle, issuing from the Capsular Ligament. joint, making it a shut sac, thus performing the double oflSice of keeping the two ends in contact, and of holding the lubri- cating fluid in the joint. In addition to these, there is in the ball and socket joint another kind of ligamentous attach- ment between the two bones, called the round ligament, or Ligamentum Teres. This is a bundle of ligamentous fibres in the form of a cord, which is inserted into the summit of the rounded head of the bone, and also in the bottom of the cup-shaped cavity that receives the head. This is somewhat lax ordinarily, but not so much so but that it keeps the head from slipping out of its socket, and at the same time allows the most perfect freedom of motion. l.";!). Wh.'it arc the Ligamcntfi ? 'J’o wliat part of tho bones are they generally at- tacliedl' How are they arranged in Ginglyinus joints? Why are they sometimes found 111 Lho form of a shut sac? Describe the round ligament. AND niYSIOLOGY. Fig. 87. n Fig. 88. A Lateral View of the Ligaments of the Ilip- Joint and Pelvis. 1, The Posterior Sacro-IIiac Ligament of the Pelvis. 2, The greater Sacro- Sciatic Ligament. 3, The Lesser Sacro-Sciatic Ligament. 4, The Greater Sacro-Sciatic Notch. .5, The Lesser Sacro-Sciatic Notch. 6, The Co- tyloid Ligament around the Acetabulum. T, The Ligamentum Teres. 8, The Line of At- tachment of the Capsular Ligament of the Hip- Joint, posteriorly. The Ligament has been removed, in order to show the Joint. 9, The Obturator Ligament. The Bight Knee-Joint laid open. 1, The Lower End of the Femur cov- ered by its Articular Cartilage. 2, The Anterior Crucial Ligament. 3, The Posterior Crucial Ligament. 4, The Transverse Fasciculus adhering to the Semilunar Cartilages. 5, The Point of Attachment of the Ligamen- tum Mucosum,the rest of it has been removed. 6, The Internal Semilunar Cartilage. 7, The External Semilunar Cartilage. 8, A part of the Ligamen- tum Patellae turned downwards. 9, Its Bursa laid open. 10, The Supe- rior Peroneo-Tibial Articulation. 11, The Interosseous Ligament. 160. Aid of Atmospheric Pressure. — Atmospheric pres- sure also helps to keep the bones together. For since the projection of one member so accurately fits the depression in the other, and as the lubricating fluid makes the coupling most perfect, the pressure of the atmosphere assists not a little to keep the parts together. 161. Inter-articular Cartilage. — Another arrangement in the joints is not a little singular, and well adapted to its pur- pose. This is an interarticular cartilage in the knee called semilunar, or a small disc of cartilage which lies loosely bo- IGO. What besides the ligaments helps to keep the bones together ? ICl. Describe the interarticular cartilage and its use. 4 72 HITCHCOCK’S ANATOMY Eig. 89. A View of the Articulation of the Lower Jaw, given by sawing through the Joint. 1, The Glenoid Fossa. 2, The Tubercle for the Condyle in its Forward iiiove- inents. 8, The Inter- Articular Cartilage. 4, The Superior Synovial Cavity. 5, The Inferior Synovial C.avity. 6, The Inter- Articular Cartilage removed from the Joint and seen from below. Fig. 90. An Anterior View of the Ligaments of the Vertebrfe and Ribs. 1, The Anterior Vertebral Ligament. 2, The Anterior Costo- vertebral Ligament. 3, The Internal Transverse Ligament. 4, The Inter-Ar- ticular Ligament, connecting the Head of the Rib to the Inlervertcbral Sub- stance. tween the bones. The design of it is to distribute the fric- tion over a larger surface, as well as to diminish it. Fig. 91. 162. In Fig. 90 we see the mode of attachment be- tween the vertebrae and ribs which is that of three dis- tinct ligaments to each rib, besides one common to each pair of ribs. Fig. 91 shows the anatomy of the elbow- joint. Here are no less than four distinct ligaments. We see in Fig. 92 the liga- An Internal View of the Elbow- Joint. 1, The Capsular Ligament. 2, 2, The In- ternal Lateral Ligament. 3, The Coro- nary Ligament. 4, The Ligamentum Te- res. 5, The Interosseous Ligament. 6, The Internal Condyle, which conceals tho Capsular Ligament behind. 1C2. Describe tho ligaments in Figs. 90, 91, 92 and 93. 163. How are the joints lubri- cated ? AND PHYSIOLOGY IS merits 'which unite the lower end of the fibula to the tibia and the tarsal bones, and in Fig. 93 the ligaments of the foot, 163,. Synovial Membrane and its Secretion. — The lubrication of the joints is effected by means of a thin membrane lining their cavi- ties which secretes an oily substance called the Synovia, (Fig. 94, p. 74), that is con- stantly applied to the oppos- ing surfaces. In health the action of the joint stimulates this membrane to the secre- tion of a proper amount of A Posterior View of the Ankle-Joint of the Left Side. 1, The Interosseous Liga- ment of the Bones of the Leg. 2, The Posterior Inferior Ligament connecting the Tibia and Fibula. 3, The Transverse, or Long Fibres of the same Ligament 4, The Internal Lateral Ligament. 5, The Posterior Fasciculus of the External Lat- eral Ligament. 6, The Middle Fascicu- lus of the same. 7, The Synovial Capsule 8, The Os Calcis. Fig. 93. 13 bl- II A Vertical Section of the Ankle-Joint and Foot of the Right Side. 1, The Tibia, 2, The Astragalus. 3, Os Calcis. 4, The Scaphoides. 5, The Cuneiforme Internum. 6, The Metatarsal Bone of the Great Toe. 7, The First Phalanx of the Great Toe. 8, The Second Phalanx of the Great Toe. 9, The Articular Cavity between the Tibia and Astragalus, with its Articular Adipose Matter. 10, The Synovial Capsule between the Astragalus and Calcis. 11, The Calcaneo-Astragalian Interosseous Ligament. 12, The Synovial Capsule between the Astragalus and Scaphoides. 13, The Calcaneo- Scaphoid Ligament. 14, The Calcaneo-Cuboid Ligament. 15, The Synovial Capsule between the Scaphoides and Cuneiforme Internum. 16, The Synovial Capsule between the Cuneiforme Internum and the First Metatarsal Bone. 17, Tlie Metatarso-Pha- langial Articulation of the Great Toe, with the Sesamoid Bones below, 18, The Pha- l.ingial Articulation of the Great Toe. HITCHCOCK’S ANATOMY 74 Fig. 94. An Internal View of the Ankle-Joint of the Kight Side. 1, Internal Malleolus. 2, 2, Part of the Astragalus, tae rest being concealed by Ligaments. 3, Os Calcis. 4, Scaphoides. 5, Internal Cuneiform Bone. G, Internal Lateral, or Deltoid Ligament. 7. The Synovial Capsule, covered by a few Fibres of a Capsular Ligament. 8, Tendo A between this Tendon and the Tuberosity of synovia, the superabundance of which (when it is present) is removed by the absorb- ent vessels. This lubricating fluid, however, is not poured out directly upon the ends of the bones, but upon smooth and elastic cartilage, which is found in every joint, not only for furnishing a smooth articular surface, but also to diminish the force of jars by its clastic character. diillis. A small Bursa is seen tho Os Calcis. FUNCTIONS OR USES OF THE BONEg. 164. The uses of the bones may be classed under three divisions : First, for a framework to the whole system. Second, to furnish points of attachment to muscles and ligaments. Third, to protect 'the softer parts. 165. A Framework. Ligaments used as Braces and Pins, — Exactly as a human architect plans and constructs a frame to the house, so the Great Architect has formed the bones. Each bone is fitted exactly to the position, size, and use of the part where it is placed, and nowhere can a supernumerary bone be found. In the house to be built, braces and joining pins must be employed, and those generally of a tougher material than tho frame itself. So in the human body, liga- AVliy is cartilage useful in the lubrication of Joints? IGL Give the uses of the bones as classed above. 105. Compare the boues and ligaments with tho timbers, braces and ]iius of a house. AND PHYSIOLOGY. 'i’a ments and cartilage exist wherever two opposite extremities need strength and support to keep them in their places. In the railway locomotive immense strength is required, and at the same time perfect freedom of motion in certain positions, all of which is effected by the ponderous bars, levers and wheels, perfectly secured by bolts, keys and screws. But in the human frame by how much more simple means is the same end secured. No angular or cylindrical couplings secure the human joints, though beautifully adapted to pro- duce movement in every direction, and no attention or care is necessary to lubricate and preserve in ^ good condition the working parts of this machine, but a few tough fibers and membranes, secure at once in a most perfect manner every portion of the frame, and provide at the same time means for its lubrication. 166. Use of the Anomalous Forms of Bones. — The bones are fitted for the attachment of muscles and ligaments. Hence it is that they are of such anomalous and curi- ous forms, apparently constructed without design or pur- pose. But as we study them, and understand the various motions which they must perform, as well as the organs which many of them must protect, or provide space for, we find that it is impossible to improve in the slightest degree on the construction of the skeleton. The size, the form, the quality of material, the exact position of every process, curve and foramen of the bones, and the manner in which all are arranged, are most wisely adapted to their functions and to the happiness of the vertebrated race. 167. Reason why the long Bones are Tubes. — In this connection should be mentioned the reason why the long bones are hollow. It is for the same cause that the stems of grasses, grains, and many other vegetables are hollow cylin- ders, instead of solid rods : to secure great strength with as 166. Why are the bones of such peculiar shapes ? 167. Give the reason why many of the bones are hollow. 76 HITCHCOCK’S ANATOMY little material as possible. For example, were the liuman femur a solid rod, instead of a hollow cylinder, as it now is, it would require a bone twice the diameter of the present one to be sufficiently strong for the purposes required of it. Hence were the whole skeleton constructed on this principle, it Avould be so cumbersome and heavy that it would require a larger amount of muscle, making the body unwieldy, and thus deprive it of its rapid and easy motion. 168. Protection given to the Brain. Use of the Diploc. Reason for several Bones in the Skull The bones af- ford much protection to all the enclosed and adjacent or- gans. In the bones of the head, for example, how perfect the guard over the nervous center. Here arc three means for protection, two plates of bone, and an intervening cel- lular space. The outer table being very tough presents a substance somewhat yielding to blows inflicted by pointed substances, and even if the blow be so severe as to cause fracture, this can not extend so far as in a hard and brittle material. And the intervening space or diploc very materially deadens the force of any shock given to the outside of the head, precisely as the springs of a carriage prevent the unevenness of the road from giving the same sudden jolt to the body that is communicated to the wheels. The inner table is necessarily brittle, since the brain de- mands the firmest possible support. But why is the skull made up of several bones instead of one ? In the first place a more symmetrical growth can be effected, provided the points of increase are numerous, and especially so since in early life, while the growth is going on, there is a thin layer of cartilage between the edges of each bone, thus allowing all necessary motion; secondly, because a fracture can not extend furthei than a suture, as all the vibrations are overcome by the inter- position of any soft substance like cartilage. And for this lOS. llow do tlio l)onos afford a protection to the softer parts? What is tho use of tho dipl66 in tho hones of tho skull? Stuto tho reason of several- hones in tho skull. AND PHYSIOLOGY. 77 reason the jar of any blow is greatly lessened by the same cause. 169. Use of the Ribs. — Again we see the bones of the thorax arranged for the protection of the enclosed organs. Within this cavity are organs delicate and easily destroyed, but which require elastic and movable walls. The elasticity is- easily gained by the cartilaginous portion of the ribs at- tached to the sternum, which yields considerably upon pres- sure ; and the motion and consequent enlargement is effected by the oblique position of the ribs, as they run downwards and forwards from their articulation with the vertebrae. As the vertebral extremity is the fixed point,, of course the eleva- tion of the sternal end will enlarge the cavity of the thorax antero-posteriorly. Another use of the cartilaginous extrem- ity of the ribs is to lessen the chance of fracture. The tho- rax is exposed to blows and falls more than many other por- tions of the body, and therefore more exposed to fracture. For instance, if a person suddenly falls to the ground, the head by an instinctive movement is raised, while the trunk or extremities receive the force of the shock. Also the head or extremities can by rapid movements be suddenly removed from the contact with missiles, while the body, comparatively unwieldy, must meet the blow. 170. Use of the Iiinomiiiata. — The expanded condition of the Innominatum affords service and protection in different ways. A depression, or cup-shaped cavity is thus made for giving a firm support to the organs contained in the abdomen, as Avell as a solid foundation to the spinal column. It how- ever renders especial service by furnishing a powerful point of attachment for many of the muscles both above and below : those which form the walls of the abdomen, and many of those which move the extremities. 171. Why there are so many Bones in the Spinal 1G9^ Describe the uses of the ribs, and the reason M’by they are partly made up of car- tilage. Why do they run obliquely from the points of attachment? 170. Explain why the Innominata are so broadly expanded. 18 HITCHCOCK’S anatomy Column. — A large number of bones in the spinal column is necessary in order to give flexibility to the body. Were the number considerably less, the movements of the trunk would be attended with much more difiiculty than at present, and bo devoid of grace. And were the separated vertebrm long bones, they would be much more easily broken, thereby en- dangering the spinal marrow. Another reason for the great number of these bones, is the necessity of the elastic cartilage between them, to protect the brain. Were the joints fewer, in order to give equal protection to the brain from jars, this cartilage must of necessity have been greatly thickened, thereby weakening the joint, and injuring it as a central axis of support to the whole body, and also increasing the liabil- ity to dislocations, as well as greatly endangering life, by pressure upon the spinal cord. 172. Use of the Clavicle. — The value of the clavicle lies in keeping the upper extremity in its proper position, so as to prevent the humerus from coming forward towards the middle portion of the body. By its direct resistance it also assists in some muscular actions, such as lifting heavy weights with the hands. 173. Need of two Bones in the Fore -Arm. — The use of two bones in the fore-arm, as already mentioned, is to pro- duce the movements of supination and pronation. And since these movements are of primary importance, and one bone can not answer this end, two are provided. Again, if one be fractured, the other will act as a splint for keeping the broken one in place, greatly superior to the artificial splint, because the natural splint needs no compression. 174. Why several Bones in the Carpus. — In the carpus are found eight bones, and yet ^ye know there is but little motion between them. The reason Avhy exactly this number 171. AVliJit is tho reason why so many bones aro i)lace(l in the spinal column? AVliat is llio iiso of tho intervertebral substance ? 172. AVliat service does tho clavicle render 1o the upper extremities? 173. Why are there two bones in the forc-arm? 174. What can be said of tlie many bones of tho carpus ? AND PHYSIOLOGY. V9 is required, is not so easily explained, but it is evident that one bone could not perform their function, nor the prolonga- tion of the radius and ulna to the metacarpus. Several bones are required in order to give easy and graceful motion to the wrist, as well as strength. One bone could not answer the purpose, since the very many oflSces, which the hand has to perform, could not be effected, unless the wrist bones were very strongly bound together, and flexible to a certain extent. The arrangement of the bones in two rows allows a little movement of the hand upon the wTist. 175. Function of Metacarpus — The metacarpus of five long bones gives support to the fingers. They are long rather than short bones, in order to give slenderness to the hand, and also to afford a solid surface for the fingers to meet in the act of prehension. 176. Need of three Phalanges to the Fingers, and two Phalanges to the Thumb. — The phalanges of each finger are three in number, whilst those of the thumb are but two. The obvious reason of this is to give greater firmness to the thumb, and flexibility to the fingers. The hand in man dif- fers from the anterior extremity of all other animals in the power of perfectly opposing the thumb to each of the fingers, which of course gives him a great superiority in all delicate manipulations, and especially in grasping minute objects. And it is easy to see that a third phalanx in the thumb would not only diminish the firmness of this member, but would render the hand an awkward and clumsy organ, instead of an instrument beautifully and perfectly adapted to the multi- farious offices which it has to perform. 177. The great length of the lower Extremities. Pe-, culiarities of the Femur. — The value of the great length in the lower extremities, is manifest as a means of rapid pro- Why would not one bone be sufficient? 175. The use of the metacarpus. 176. Why are there but two phalanges in the thumb and three in each finger? What would be the effect of a third phalanx in the thumb ? 177. Why are the lower extremities pro- portionally longer than the upper ? 4 ^ 80 HITCHCOCK’S anatomy gression, and also for affording a firm support to tlic trunk when engaged in the various kinds of labor. Were tiiese ex- tremities much shorter than they now are, walking would not only be a tediously slow process, but a laborious one. The femur has some remarkable peculiarities. In the first place it presents in its articulation with the innominatum the most perfect specimen of a ball and socket joint in the system. Besides this it bends at nearly a right angle at its upper end, making what is called the neck, and here it is that the frac- ture of the thigh-bone generally occurs. The use of this curvature is to place the points of support for the trunk as far as possible from the center of gravity of the body, thereby giving the body the most secure position on the lower ex- tremities, and especially for the attachment of powerful muscles to move the thigh and leg, as well as to maintain securely the trunk when the legs are the fixed points. This projection is called the Trochanter process, and is spongy or cellular in its structure. And it is not a little interesting to notice, when this process is sawn through in a perpendicular direction, that the cells are arranged in an arched form from below upwards, thereby greatly aiding the strength of the bone. The same arrangement is seen in some other bones of the body, when they are in an exposed position. The lower extremity of this bone, as has already been mentioned, is greatly expanded, in the shape of two condyles for the firm articulation with the tibia. The necessity for this lies in the fact that the knee-joint is one of the most exposed joints in the whole body, and the one which receives the hardest strain. The protection of the nerves and blood vessels, which are sent to the leg, is also worthy of a notice. It is effected by a deep groove between the condyles on the backside of the leg, which guards these vessels from blows in every direc- tion except behind, from whence they are the least apt to come. What remarkable joint between the femur and the innorninata? What is the ar- rangement of tlio cellular structure in the upper part of the femur? Why has the fe- mur so largo i)roces.se3 on its lower extremity ? AND PHYSIOLOGY. 81 178. Use of t li e Tarsus . — In the Tarsus we see the value of several bones instead of one. It is the movement of these upon one another that imparts elasticity to the step and firm- ness of support to the whole body ; and hence it is that all artificial legs produce a limping motion in the body. By no mechanical contrivance can the suppleness of the tarsus and of the muscular actions be supplied. ‘ 179. Two Bones in the Great Toe, and three Bones in all the Others . — The great toe of the foot, like the thumb of the hand, has only two phalanges. This is mainly for the purpose of securing greater strength to the foot in walking and standing. It is also of service for opposition to the other toes, as is seen in those rare cases of persons deprived of their upper extremities, who can readily make use of the foot for many of the delicate purposes to which the hand is adapted, such as writing, using scissors, and placing the crystal in a watch. The remaining toes, like four of tlie fingers, receive a tendon only at the base of the second and third phalanx, the first one being interposed merely to give strength and slenderness to the extremities, as well as the power of sur- rounding objects in the act of prehension. The slenderness of the fingers above the toes is a distinguishing characteristic of man, showing that the office of the foot is merely to sup- port the body on the ground, and of the hand to perform the business of every-day life in its ten thousand forms. HYGIENIC INFERENCES. 180. — 1. Reason of Bistorted Bones.— In the early life of man and other vertebrate animals, the animal portion of bones greatly predominates over the earthy constituents, and hence they yield more readily to pressure, but are not so 178. IIow do the bones of the Tarsns give elastieity to the step? 179. TIow do the phalanges of the foot compare with those of the hand in number? Why are the bones of the hand longer than those of the foot ? ISO. What kind of matter predominates in the early life of bones ? 82 HITCHCOCK’S ANATOMY liable to break as in older persons. Tliis is the reason why falls and blows so seldom do much injury to children. It is also the reason wdiy distortions and curvatures of some of the bones are so common, since too often children are either urjzcd or j)crmitted to use their limbs excessively before their bones are made vsolid by the deposition of earthy matter. These distortions are most common in children who arc weak and sickly, because in them the recuperative powers are small. 181. — 2. Danger of Constrained and Unnatural Posi- tions in Children, — Hence w^e infer that children should not be confined in any unnatural or constrained position, but allowed to move freely in whatever direction nature may de- mand. And all punishments of this sort, inflicted by parents, guardians, and school teachers upon young persons, such as standing on one leg, or holding a book with an extended arm for a long time, are dangerous and ought to be proscribed, since they are too often the cause of bow legs and curvature of the spinal column. 182. — 3. Cause of the Rickets. — The disease known as Rickets is produced by imperfect nutrition of the bones. This is generally, though not always, the result of poverty or vice, or both combined. The direct cause of the disease is a de- ficiency of earthy matter in the bones. This is either ab- sorbed or never produced, and as a result the bone is softened^ and by the tonicity of the muscles the body is drawm into un- sightly deformity. An observance of the laws of health is the best medicine for this disease. 183. — 4. Need of Cleanliness of the Teeth — Tooth Pow- ders — Tooth Picks — Decayed Teeth — Worthless Teeth should he E x t r a c t e d . — From the almost inevitable exposure of the teeth to mechanical and chemical agents, we see that they need considerable care and attention. They need to he W'liy do falls and blows seldom injure cliildrcn as they do adults ? In what children are distortions the most common ? ISl. W^’hy should children ho unconstrained in their bodily exercise ? W’hut is said about punishments that m[)lete Fracture, follow- ing tlie opposite surfaces of a Disc which stretches across the Interval and retains the two Fragments in connexi >n. The Edge and Surface of this Disc are seen to be minutely granular, the Granules corresi)on(ling in size to the thickness of the Disc and to the dis- tance between the faint Longitudinal Lines. 4, Another Disc nearly detached. 5, A de- tached Disc more highly magnified, showing the Sarcous Elements. 6, Fibrilhe separated by violence from each other at the broken end of the Fiber. 7, 8, The tw(» appearances commonly presented by the separated single Fibrillae ; more highly magnified, at 7 the spaces are rectangular, at 8 the borders are scalloped and the spaces bead-like. of an inch, and number about 650 in each ultimate fiber. They are unprotected hy any covering, while both the fasicu- ■piQ, 122. and ultimate fiber are everywhere pro- tected by a delicate sheath called the Sarcolemma. 230. Organic, or Unslripcd, and Ani- mal, or Striped Fi- Fibrils of Human Muscle. tcrS. All the mUS- cles of the body are divided into two classes, according to their function. Those necessary for carrying on the vital functions, such as breathing and digestion, are called Or- ganic, and those under the control of the will Animal Fi- bers. In addition to their use as a means of distinction, they may be known by their appearance under the micro- What is the Sarcolemma ? On what clement of muscle is this wanting? 230. Give the two functional classes of the muscles. AND PHYSIOLOGY. 109 Fm. 123. Transverse Section of Human Fibrillje showing a Polygonal form. scope, the Animal Fiber being marked by transverse striiB, or stripes resembling a beaded filament, called Striped Fi- ber ; and the Organic being made up merely of flattened bands destitute of these cross marks, and hence called Un- striped, or smooth fiber. The unstriped fibrils are developed from cylindrical or spindle- shaped nucleated cells, and are surrounded by a peculiar fluid known as muscle j uice, which is unlike the plasma of the blood, since it contains casein. 231. Tendons, Aponeuro- ses, Bellyor Swcllof IheMus- c!e. — The extremities of the muscles are composed of dense areolar tissue in the form of tendons or cords, and that extremity which is nearest to the center of motion is called Fig. 124. A broken Muscular Fiber showing tho sheath or myolemma untorn. Fig. 125. ber. a, Two cells in their natural state. hj A cell treated to acetic? acid, showing the nucleus c. the Origin, while the one most What is the appearance of the Animal Fibre under tho microscope? Also that of the Organic? 2S1. State the composition of the Tendons. no HITCHCOCK’S ANATOMY remote from it is called its Insertion. These are exceedingly firm and strong, perfectly inelastic, and can not be torn from the bones without unnatural violence. If the extremity of the muscle has a large surface for attachment, its tendon is expanded into a broad membranous portion termed an Apo- neurosis, as may be seen in the muscles inclosing the abdo- men ; while the greater portion of the muscles have a fleshy portion called the Swell or Belly, and the tendinous portion contracted into the shape of a cord, or even of a thread. In general this belly of the muscle is in a place which is the most firmly fixed, and distant from the point to be moved, in order to efiect grace of motion, and beauty of form. Fig. 12G. A Eadiate Muscle. 232. Forms of Muscles. — In form the muscles present a great diversity. A Radiate Muscle (Fig. 126) is one where the fibres radiate from a central portion to distribute them- selves upon a large surface. In the Fusiform (Fig. 127) the Fig. 121. A Fusiform Muscle. fibres diminish in size from a center to each extremity. In What is the fleshy portion of the muscle called ? What is an Aponeurosis ? Define the Origin and Insertion of a muscle. WHiere is the Belly of the musele generally located? 233. Describe the Eat muscles given to them? 247. ITow many pairs of muscles upon tlic hack of tho body? Givo tho number of layers into which they maybe ortion of the Longitudinal Fibers of the Muscular Coat. 7, The Circular Fibers of the Muscular Coat. 8, The Oblique Muscular Fibers, or Muscle of Gavard. 9, A portion of the Muscular Coat of the Duodenum, where its Pe- ritoneal Coat has been removed. they may contract in the most efficient manner upon the con- tents of the stomach for the purpose of digestion, and forcing the contents onwards into the Duodenum. They also assist in forcing the contents of the stomach backward in vomiting. In the inner or mucous lining are situated an immense num- 294. "Where is the Stomach situated? What is its normal size? How many coats has it and what are they? Of what service is the muscular coat? What glands are con- tained in the mucous membrane of the stomach ? 160 HITCHCOCK’S ANATOMY ber of tubular glands which open directly into the stomach. They are cup-shaped cavities about the asVexth of an inch in diameter, and jVth in length, from the bottom of which pro- ject two or more parallel tubes, ending in a closed termina- tion in the tissue beneath. These compose tlie greater por- Fw- 111- F:g. 172. Diagram of tbo Stomach and Intestines. 1, Stomach. 2, Esophagus. 8 and 4, Stomacli. 5 and G, Duode- num. 7, Jejunum. 8, Ileum. 9, Csucum. 10, Vor- inlforin Appendix. 11, 12, 18, 14, Colon. 15, Rectum. Stomacli, magnified forty-five dia" meters. 1, A Gastric Gland, from the middle of tlie Stomach. 2, An- other, of more com[)lcx structure, and appearing to contain Mucus — from the neighborhood of the Pylorus. tion of the mucous mem- brane, and are for the purpose of secreting the gastric juice, and prob- ably the Pepsin also. In addition to these glands, a large number of the mouths of veins open into the stomach, which act the part of absorbent vessels to remove the water, whether pure or mixed with other sub- stances. 295. Duodenum. — The first division of the Intestines is the Duo- AND PHYSIOLOGY. 161 denuni; because in length it is equal to the breadth of twelve fingers. It commences with the pyloric orifice on the right extremity of the stomach, and runs slightly backwards and upwards until it terminates in the Jejunum. It is often called the second stomach, because a certain part of digestion takes place here, and the food passes slowly and receives no less than three different secretions : one from the Liver, an- other from the Pancreas, and the third from the Mucous membrane of the intestine itself. 296. Jejunum. — Next below the Duodenum is the Jeju- num, meaning ‘‘empty,’’ since it is always found in this con- dition after death. This, like the other divisions of the intes- tine, has three coats, and is of a slightly pinkish color, be- cause here the mucous membrane is thicker than in any other of the intestines. Us. 297. Ileum. — The Ileum (from the Greek signifying to twist) is the third division of the Intestines, and is about fifteen feet in length. It is the smallest Intestine, and has a darker color than either of those already mentioned, and is exceedingly tortuous in its course. 298. Caecum. — The fourth division of the Intestine is the Caecum. This is a shut sac much larger than the small Intestine, and of a The Caecum and its Appendix. 1, Cae- cum. 2, Colon. 3, Ileum. 4, Entrance from Ileum to Colon. 5, llio-Caecal Valve. 6, T, 9, Parts of the Appendix Caeci. What do they secrete ? What vessels open into the stomach, and of what service are they? 295. What is the Duodenum ? Give its general course. Why is it sometimes called the second stomach? What fluids are poured into it? 296. What is the name Jejunum derived from? What is its color? 297. How long is the Ileum? What is said of its shape? 298. Name the fourth divison of the intestines. Describe it. 1G2 11 1 T C II G O 0 K ’ S ANATOMY grayish blue color, and not exceeding three inches in length. The entrance of the Ilium into the Caecum is effected by a valvular arrangement Avhich allows the food to pass into the Caecum, but never in the opposite direction. It is situated at the right Innominatum in the lower part of the abdomen, and its lowest portion has a worm-shaped process attached to it, which is only rudimentary, and consequently of no great service to man, but largely developed and of great service in some of the lower animals, and especially in the herbivorous ones. 299. Colon. — The Colon (from the Greek signifying ‘Go prohibit,’’ since the food passes very slowly through this part of the canal), commences at the Caecum on the right side of the abdomen, and in the first part of its course passes in an upward direction, and is called the ascending Colon. When it reaches the lower edge of the liver, it crosses horizontally to the extreme left edge of the body, constituting the trans- verse Colon. After this it descends, and joins the Rectum, forming the descending Colon. Its length is from five to eight feet. 800. Rectum. — The Rectum completes the divisions of the Intestines. It is nearly straight in its course, of a larger size than any other division of the canal, except the stomach, and from six to eight inches in length. Its name is derived from the straight direction which it assumes. 301. Division of the Intestines into small and large. — The last three divisions have a much larger diameter than the first three, and are called on that account the large Intes- tine, and the Duodenum, Jejunum and Ilium, the small In- testine. The latter seems to be the portion necessary for preparing the food to enter the Lacteals, while the large In- testines act mainly as a receptacle for the waste portion. Where Is its location in the body ? What curious appendage is attached to it? 299. What arc the three divisions of the Colon? How lon^ is it? 800. What does the Colon terminate in? Ifow lonj' is tlio Kectuui? 801. Dcliao the largo and tho small Intestine, and give their probablo uses. AITD PHYSIOLOGY. 163 Fig. lU. Liyer. Pylorus. Gullet. Pancreas \ \ ' ' Gall-Bladder. Large Intestine. Caecum., Appendix of the Caecum. Stomach. Spleen. Colon. Small Intestine. • Colon. Small Intestine. Pectum. Digestive Apparatus in Man. 302. Structure of Intestines, Intestinal Glands. — Like the Stomach, the Intestines are formed by three membranes. Also in the inner or mucous membrane are situated an im- mense number of microscopic glands, so that a French teacher speaks of them existing ‘^as numerous as the stars in the starry heavens.’’ They are distinguished as Duodenal Glands, Brunner’s Glands, Solitary Glands, Peyer’s Patches, and Follicles of Lieberkiihn. (Fig. 175, p. 164.) They are most abundant along the course of the Ileum and they seem to be especially affected in Typhoid Fever, although no cer- tain use for them in health has as yet been discovered. The 302. What is the stnicture of the Alimentary Tube .? What is said of the Glands found in its mucous lining ? State their names. 164 II I T C TI C O C K ’ S A X A T O ]\r Y Follicles of Licbcrkiilin arc found only in the large intestine. T li o Mucous membrane of this part of the canal, is not smooth and con- tinuous with the serous or outer layer, but is doubled upon itself in a great number of folds, in order that the surface containing these glands may be the largest that is possible, so that the contents of the Intestine may receive a large supply from these secretions. Minute Villi or hair- like pro- jections are also found in great abundance upon this mem- A Portion of the Ilium highly magnified, show- ing Peyer's Patches and the Villi. Fig. 176. Fig. 177. A Portion of one of Brunner’s Glands. A View of a Longitudinal Section of the Jejunum, showing the Villi as seen under the Microscope. 1, 1, The Terminal Orifices of the Villi. 2, 2, The Internal Coats of the Intestine. 3, The Peritoneal Coat. How is the Mucous membrane arranged through the canal, and what is the design of such an arrangement? AKD PHYSIOLOGY. 165 brane, in order to increase the amount of its secretory surface. It is the presence of villi that gives to some parts of the mu- cous membrane a velvet-like appearance, and in these villi are found the commencement of the lacteals, one lacteal usually being found in each villus. 303. Glands attached to the Intestines. — Connected with the Alimentary Canal are several large glands, a few of which have already been described. They are soft solids, of various forms and sizes, and are composed of lobules or small divisions, each one of which is supplied with an artery, vein, and duct. Each of these ducts communicates with the prin- cipal duct or outlet, which conveys away the product sepa- rated from the blood by the whole gland. In microscopic structure, a gland is made up of very minute cells, which seem to have the power of secreting or separating from the blood the particular substance which it is the function of the gland to eliminate. 304. The liver, Gall-Bladder, — First in importance of this class is the Liver. (Fig. 178, p. 166.) This, except- ing the brain, is the largest organ in the body, and is situated on the right side of the abdomen, corresponding to the stom- ach on the left, and is of a reddish yellow color. The average weight of it is four pounds, measuring twelve inches in its longest diameter, and it is divided into five lobes or great divis- ions, and these are entirely composed of minute bodies or lobules, (Fig. 179, p. 166), w^hich are about the size of millet seeds, each one containing an artery, a vein, and a plexus, or net- work of ducts for conveying away the bile. These differ- ent plexuses unite with each other and form two hepatic ducts which discharge the bile into the Gall Cyst or bladder. (Fig. 180, p. 167.) This is a pear-shaped sac, containing from one to two ounces, of a greenish yellow color, situated under Describe the Villi. 303. What is said of the lar^e glands connected with the organs of digestion? State the structure of a gland. 304. What is the relative size of the Liver? Where is it located ? State its color and weight. Give its minute structure. What is the Gall Cyst or Bladder ? What is the duct that carries the Bile to the Gall Cyst, and the one that empties the Gall Cyst into the Duodenum ? IGG HITCHCOCK’S ANATOMY Fig. 178. The Inferior or Concave Surface of the Liver, showing its Subdivisions into Lobes. I, Center of the Eight Lobe. 2, Center of the Left Lobe. 3, Its Anterior, Inferior, or Thin Margin. 4, Its Posterior, Thick or Diaphragmatic Portion. 6, The Eight Extrem- ity. 6, The Left Extremity. 7, The Notch on the Anterior Margin. 8, The Umbilical or Longitudinal Fissure. 0, The Eound Ligament or remains of the Umbilical Vein. 10, The Portion of the Suspensory Ligament in connection with the Eound Ligament. II, Pons Ilepatis, or Band of Liver across tlio Umbilical Fissure. 12, Posterior End of Longitudinal Fissure. 13, 14, Attachment of the Obliterated Ductus Venosus to the Ascending Vena Cava. 15, Transverse Fissure. IG, Section of the Hepatic Duct. 17, Hepatic Artery. IS, Its Branches. 19, Vena Portarum. 20, Its Sinus, or Division into Eight and Left Branches. 21, Fibrous remains of the Ductus Venosus. 22, Gall-Blad- der. 23, Its Neck. 24, Lobulus Quartus. 25, Lobulus Spigelii. 26, Lobulus Caudatus. 27, Inferior Vena Cava. 28, Curvature of Liver to fit the Ascending Colon. 29, De- I)ression to fit the Eight Kidney. 30, Upper portion of its Eight Concave Surface over the Eenal Capsule. 31, Portion of Liver uncovered by the Peritoneum. 32, Inferior Edge of the Coronary Ligament in the Liver. 33, Depression made by the Vertebral Column. Fig. 179. the right side of the liver, and has a small vessel called the Bile Duct, which enters the Duode- num obliquely about three inches from the stomach. 305. Pancreas. — The Pancreas (^^all flesh,’’ because there is no fat ever found in it) is another Transverso Boction of a Lobule of the Humau Liver. AND PHYSIOLOGY 167 Fia. 180 . A View of the Gall-Bladder distended with Air, and with its Vessels Injected. 1, Cystic Artery. 2, The Branches of it which supply the Peritoneal Coat of the Liver. 8, The Branch of the Hepatic Artery which goes to the Gall-Bladder. 4, The Lymphatics of the Gall-Bladder. gland, lying directly behind the stomach. It is about six inches in length, the right end of it being somewhat larger than the left extremity, and hence called the head. To the naked eye the lobular structure is apparent : but each lobule is itself made up of much smaller lobules. The duct of the Pancreas conveys the milk-like secretion of this gland, to nearly the same point on the Duodenum as the Hepatic Duct, where they both enter that tube in a slanting manner, so that by the valvular arrangement the contents of the intestine can not be forced backwards into the Biliary or Pancreatic duct. Fia. 181 . 3 An Anterior View of the Pancreas, Spleen and Duodenum, with their Blood-Ves- sels Injected. 1, The Spleen. 2, Its Diaphragmatic Extremity. 3, Its Inferior Portion. 4, The Fissure for its Vessels. 5, The Pancreas. 6, Its Head, or the Lesser Pancreas. 7, Duodenum. 8, Coronary Arteries of the Stomach. 9, The Hepatic Artery. 10, The Splenic Artery. 11, The Splenic Vein. 805. Describe the Pancreas. What is its structure? Where does its duct empty, and what mechanical structure in it makes it remarkable ? S m HITCHCOCK’S ANATOMY Fig. 182. 306. Pcriton cum. — The Peritoneum, ‘‘cov- ering about/ ^ or exter- nal coat of the intes- tines is not a little pe- culiar in its conforma- tion. This, like all serous membranes, first completely invests the organs and then is re- flected from them so as to make a lining for the whole cavity. Hence the cavity of the ab- domen, although a per- fectly shut sac, is of very irregular outline. That it is a shut sac may be seen from the fact that in dropsy of the abdomen — the fluid has no means of escape except by absorption, or puncture from the out- side. In the disease commonly known as in- flammation of the bow- els, this membrane is the principal seat of the difiiculty, and the inflammation of this as well as of all other serous mem- branes, is attended with acute pain, and the progress of the disease, for better or worse, very rapid. Eeflexions of the I’eritoneum. D. Diaphragm. iS. Stomach. C. Colon.^ D. Duodenum. /*. Pan- creas. Z Small Intestine, i?. Ilectum. Blad- der. The numbers indicate the course of the Peritoneum. 307. Tlie Mesentery and tiic Omentum. — These are folds of the Peritoneum, attached to different parts of the abdomen and its viscera, which servo to retain some of the organs in- 300. What is tlio Peritoneum ? Is tlie cavity of the abdomen of a regular outline? What is the principal seat of dlsoaso in i iflammation of the bowels? 307. What is the Afcsentcry and the Omentum ? Wh it is it thickly packed with? AND PHYSIOLOGY. 1G9 their positions, and also, from the amount of fat contained in them, to protect the intestines from cold and mechanical violence, and to furnish a soft surface for them to glide over in their various movements. In a lateral view of the abdo- men, Fig. 182, some of the parts of the Omentum and Me- sentery may be seen. At 4 is seen what is known as the lesser Omentum, connecting the Liver and the Stomach. At 5 and 6 are seen the folds which constitute the greater Omentum. At 10 is found the Mesentery, which encircles the small intestines. This is a broad fold of the Peritoneum connected to the middle of the cylinder of the Jejunum and Ileum through their whole length, and is attached to the posterior wall of the abdomen. Within the layers of the Me- sentery are found from 130 to 150 bodies of almond shape and size, known as the Mesenteric Glands. Through these the Lacteals pass on their way to form the Thoracic Duct. 808. lacteals. — The Lacteals are minute vessels, which commence with the inner or mucous coat of the intestines, Fig. 183. Aorta. Thoracic Canal. Lymphatic Glands. Intestine. ( Radicles of th < Chyliferous I Vessels. of the Lacteals. Mesenteiy, Chyliferous Vessels. What small bodies are found in it, and what is the use of the Mesentery ? 170 HITCHCOCK’S A X A T O H Y Fig. 184. and terminate in the Thoracic Duct. These at their com- mencement arc a))out the same in anatomy >vith the radicles or small veins, and at this point act the part of absorbents. Soon after they have left the Intestines, sev- eral of them unite into one and pass through small bodies of about the size of peas, called the Mesenteric Glands. As they emerge from these glands, they are fewer in number but larger in size, until they all unite into one tube called the Thoracic Duct, a little larger than a goose quill, at about the point of the last Dorsal Vertebra. This vessel passes immedi- ately upwards, lying closely upon the Spinal Column, sometimes separating into two smaller tubes for a few^ inches, A View of the Course and Termination of the Thoracic Duct. 1, Arch of the Aorta. Thoracic Aorta. 3, Abdominal Aorta. 4, Arteria Innominata. 5, Left Carotid. 6, Left Sub-Clavian. 7, Superior Cava. 8, The two Venae Inuominatae. 9, The Internal Jugular and Sub-Clavian Vein at each side. 10, The Vena Azygos. 11, The Termina- tion of the Vena Ilerni-Azygos in the Vena Azygos. 12, The Receptaculum Chyli ; sev- eral Lymphatic Trunks are seen opening into it. 13, The Thoracic Duct dividing, op- posite the Middle Dorsal Vertebra, into two branches, which soon re-unite; the course of the Duct behind the Arch of the Aorta and Left Sub-Clavian Aorta is shown by a Dotted Line. 14, The Duct making its turn at the Root of the Neck and receiving se\'- eral Lymphatic Trunks previous to terminating in the Posterior Angle of the Junction of the Internal Jugular and Sub-Clavian Veins. 15, The Termination of the Trunk of the Lymphatics of the Upper Extremity. 30S. Where do the Lacteals begin, and where do they terminate? What do they re- Kcmble, and what do they pass through ? State the size of the Thoracic Duct, its course and termination. AND PHYSIOLOGY. in until it reaches a point as high as the clavicle, where it gradually curves forward, and joins itself to the left sub- clavian vein. The Lacteals and Thoracic Duct are all made up of three coats and present a silvery white appearance from the color of the fluid they contain. Their function is to convey the Chyle or nutrient portion of the food into the blood. 309. Kidneys. — The Kidneys are two in number, situated upon the side of the lumbar vertebrae, and are generally en- closed in a large amount of fat. Their average size is be- tween four and five inches in length, two and a half inches in breadth, and one in thickness. Their color is of a reddish yellow, and form decidedly oval, with a depression in one of the sides. Upon its upper extremity is a small body, called the Renal Capsule, and the whole organ is abundantly sup- plied with blood. The design of it seems to be the removal Fig. 186. a I c d Diagram of the Urinary Apparatus. The Kidneys, The Ureter, o, The Bladder, tf, Canal of the Urethra. A Section of the Right Kidney surmounted by the Renal Capsule. 1, Supra-Renal Capsule. 2, Cortical Portion. 3, Medullary or Tubular. 4, Two of the Calices receiving the Apex of their corresponding Cones. 5, The Infundibula. 6, The Pelvis. 7, The Ureter. Fig. 185. What vein does it empty into? What fluid docs it carry? 309. State the leading features of the Kidneys. What is found upon its upper edge ? 172 HITCHCOCK’S ANATOMY of the waste Nitrogen of the system, and many salts, espe- cially the Phosphates, which can be eliminated by no other organ. The secretion of the kidneys is the urine, upon the regular secretion of which the health of the system greatly depends. FUNCTIONS OF THE DIGESTIVE ORGANS. 310. Mastication; Use of the Tongue; Use of the Saliva. Amount of Saliva. — The first process through which the food must pass is Mastication, or reducing it to a pulp by means of the teeth and admixture of the saliva. The service of the tongue is to keep the food between the teeth and to place it in such a position that it will readily receive the saliva. The saliva is of use to moisten the food, since the gastric fluid will much more readily dissolve it than if dry or solid. It aids articu- lation and the sense of taste by keeping the lining of the mouth in a moist and pliant state. It also is of use to cleanse the mucous membrane, and by its moisture to quench or pre- vent thirst. Air is also carried by it into the stomach to aid the process of digestion. But the most important use of this fluid is the conversion of starch into sugar. This property depends mainly upon a peculiar organic active substance con- tained in it called Ptyalin, and is most active when in a state of incipient decomposition. The saliva secreted daily varies, according to diflerent authorities, from about three pounds to six pounds and a half, and is alkaline in its character. Acid, aromatic, and pungent substances increase the amount of the secretion very much. 311. Dcgliilition. A part of the Process involuntary. — After mastication, the next process is that of swallow- ing, or deglutition. The first step is to place the bolus, or mouthful, upon the back part of the tongue, when by or what fjroat iiso aro tho Kidneys? 810. Describe tlio process of Mastication. Of wliat use is tlie Saliva ? How inucli Is secreted every day ? What increases its amount? 811. Describe tho process of swallowing. AND PHYSIOLOGY, 173 the muscles of the tongue and fauces it is forced into the Pharynx. As soon as it fairly enters this passage, the mus- cles by an involuntary movement seize it, and force it rap- idly past the opening into the lungs, and at the same moment the epiglottis is forced down upon the larynx, to prevent its entrance into the trachea. This part of the pro- cess is involuntary, from the necessity of keeping the passage to the lungs open as much as possible, in order to admit air, and also from the great danger of introducing any other sub- stance. And so perfectly carried on is this function that it is seldom — compared with the frequency of deglutition — that even a fluid escapes the vigilance of this sentinel. 812. Passage of the Food through the Esophagus, — The food passes slowly through the Esophagus into the stomach, it being forced along by the contraction of the muscular fibers, aided by the oily secretion of the Esophageal glands. 813. Gastric Digestion. — As soon as the food I’eaches the stomach, the most important part of the process of digestion commences, all the previous steps being preliminary. When- ever any solid substance comes in contact with the inner or mucous membrane of the stomach, it excites the gastric glands to pour out in abundant quantity the Gastric fluid. 314. Gastric Fluid — its Amount— Pepsin. — This fluid is a transparent liquid of a little greater consistency than water, and of a perceptibly acid taste. It possesses the property of coagulating albumen, and of separating the whey or serum from the milk in a very short time, and is secreted at the rate of seventy ounces per day. This property, however, is owing to a peculiar organic compound called Pepsin, which acts after the manner of a ferment at the normal temperature of the human body. The Gastric fluid also possesses antiseptic What part of the process is under, and what part is not under the control of the will? 812. How is the food carried through the Esophagus? 313. Where does the most im- portant part of digestion take place ? What effect has any solid substance upon the Gas- tric Glands of the Stomach ? 814. What are the properties of the Gastric Fluid? How much is secreted daily ? What effect has it on the decay of substances ? 174 HITCHCOCK’S ANATOMY properties, or the power of preventing decay or putrefaction for a long time. These three properties, the acid, fermenta- tive, and antiseptic, are of service in the following manner. The acid assists in the solution of the different materials in the stomach. The Pepsin, which constitutes two thirds of the solid materials of the gastric juice, does its office by es- tablishing the lactic fermentation, such as is seen in the changes through which milk passes in hot weather. The antiseptic properties are important in order to prevent putre- faction, which would be so liable to be set up among organic substances in such a condition, and at such an elevated tem- perature as the stomach usually possesses. 315. Digestion partly depciidciit on Chemical Action. — Thus we see that this part of digestion is mainly a chemical affair, although not entirely so : since by experiments care- fully conducted in a vial outside of the body, maintaining the same temperature and all the essential conditions of digestion, the process goes on very slowly and quite imperfectly. It was found, however, that a piece of meat did digest in a vial in nine hours and a half, while that in the stomach under precisely similar circumstances, was digested in one hour and a half. 816. Digestion partly a vital Process. — Consequently to say exactly what stomach digestion is, must at present be im- possible. We can only say that it is a chemico- vital process, essentially a chemical action depending upon vital power. 317. Movements of the Stomach in Digestion.— In order to bring the food in contact with the largest amount of Gastric Fluid, the stomach, by an instinctive movement, carries its contents over the greater curve in it, from the right to the left, and returns it in a reverse direction, occupying about What constituent is it that is primarily essential in this process? 315. IIow much of the process thus far described is mainly a chemical one? What experiment proves it? .SIG. What definition can bo given of Digestion ? 317. What instinctive movements does the stomach seem to possess? AND PHYSIOLOGY. 175 three minutes for each revolution. And in order that all of it may be permeated by this fluid, contractions frequently take place in the muscular coat of the stomach, resembling a churning process. 318. Intestinal Digestion, Chyme. — The process thus far is Gastric Digestion, or that which takes place in the stomach, and the object accomplished seems to be the con- version of the nitrogenous constituents of the food into albu- minose called histogenetic digestion, or the preparation of the food to be made into the tissues of the body. But when all the food is thoroughly dissolved, or made into a liquid condi- tion called Chyme, the Pyloric orifice is opened, and the food passes into the Duodenum. .When it arrives here — and never sooner, in a healthy state — the secretions of the Liver, Pan- creas, and mucus of the Intestine mix with it, performing the second or Intestinal digestion, which is called calorifacient or heat making, since it prepares the food which supports the heat of the body. The process, however, is somewhat obscure, aD though it is certain that food is not perfectly fitted for absorp- tion until it has well completed this process. 319. Use of the Pancreatic Fluid. — The Pancreatic Fluid secreted at the rate of from five to seven ounces per day, re- sembles quite closely the Saliva, converting starch into sugar, and aiding in the absorption of fatty matters, by forming an emulsion, which, however, is much more readily formed by the presence of bile. 320. Action of the Bile, an Antacid and Excre- tory Agent. — The Bile, thrown out at the rate of fifty-four ounces a day, seems from its large quantity to be of no little importance. And since the juices of the stomach are mostly acid in their character, it seems desirable that there should be some counteracting agent, which is furnished in the SIS. What is the principal thing accomplished hy stomach digestion ? What is food called after it has passed through this process ? Describe Intestinal digestion and its use. 319. What amount of Pancreatic fluid is secreted daily ? What is its principal use ? 320. How much Bile is secreted daily ? 8 * 170 II l T C II (; O C K ’ S A N A T O M Y highly alkaline character of the biliary secretion. Another use of the bile is to remove certain materials from the blood (the carbonaceous), by allowing them to pass off with the waste portions of the food, the liver thus performing the office of an excretory organ. The liver also seems to possess the power of forming sugar and even fat, when it is not contained in the food, thus seeming to act the part of an cquilibrator in the process of blood making. And since all the blood re- turning from the small intestines passes through the liver before going to the heart, without doubt an important change is accomplished in it by the liver, although the change is as yet by no means fully understood. 321. Purposes for which Food is required. Two kinds of Materials in the Food, azotised and non-azotised. Azotised Constituents. Albamcn, Fibrine, Casein, Gela- tin. — In the animal body we find that food is required for at least three purposes : First, to build up the organism at the outset, or, in other words, to secure its first growth. Second, to maintain the organism at its normal standard after its growth is complete, or to furnish material to supply the waste which is perpetually going on while life lasts. Third, to maintain the proper temperature of the system. Hence there must be at least two kinds of material contained in the food: one that will sustain and promote the growth of the tissues called histogenetic, and another that will keep up the heat of the body to a proper standard, called calorifacient. The first of these requisites is found in food containing Nitrogen, called azotised, and the other in that with no Nitrogen, called non- azotised. Of the azotised food the most important constituents are Albumen, Fibrine, Casein, and Gelatin. Albumen is fami- liarly known as the transparent portion of an egg before it is cooked, or the white of the egg after a cooking process. It ex- ists also in the blood, muscles, and bones of all animals, and is How is its alkaline character serviceable ? What other processes does it accoinplish ? 821. What three purposes is food required for ? Hence what two kinds of food must be brought into the system ? Give examples of azotised food. AND PHYSIOLOGY. 177 coagulated or made hard and white by heat or mixture with Nitric Acid. In some parts of vegetables also, especially in the seeds and fruit, is found a substance which, from its re- semblance to animal albumen, is called vegetable albumen. Fibrine exists in the blood and muscles of animals, forming the coagulum or clot of blood, and the proper muscular sub- stance. There is also a corresponding substance in plants known as vegetable Fibrine. Casein closely resembles Albu- men in its constitution, but differs in many of its physical properties. For while Albumen is coagulated by heat. Casein is only coagulated by lactic and acetic acids. Casein is best seen in cheese. These three substances are the essential ele- ments of nutrition in mammals, and though every other prin- ciple may be supplied in the food, yet the body is insuflBciently nourished without Albumen and Fibrine. Gelatin, which exists abundantly in the cartilage of animals, is another azotised principle of food. This, however, of itself can not support life, although it can be changed into albumen, or some of its compounds by the action of the fluids of the. stomach. 322. Non-azolised Constituents. — Of the non-azotised constituents of food, the Saccharine and Farinaceous and Oily, are the principal ones, although there are many others of less importance. Of the former, the principal element is starch, while the sugar is secondary or subsidiary to it, and in the latter we find an abundance of a Hydro-Carbon, or a compound of Hydrogen, Carbon, and Oxygen, and all are essential elements in combustion. 323. Is an exclusively Animal or Vegetable Diet the best adapted to Man? Testimony of Experience. Ex- perience of Dr. Kane. — The question then which naturally suggests itself here is, whether man is adapted to live ex- Wbat effect has heat and Nitric Acid upon Albumen ? Where is Fibrine found ? How does Casein differ from Albumen? Will Gelatin (or Jelly) of itself support life ? 822. What are examples of non-azotised kinds of food? 323. Is man made to live on an ex- clusively vegetable or animal diet ? 178 HITCHCOCK’S ANATOMY clusively upon vegetable or animal diet. An answer comes to us from both experience and chemistry. For while on the one hand hundreds of examples are adduced, as showing that some men have lived to a green old age in solid health, who liavo entirely refrained from animal diet, and many others who probably Avould have shortened their lives a score of years by the use of animal food, have prolonged it by adopt- ing a vegetable regimen, an equal number of cases can be mentioned to show that a mixed diet has promoted equally long and healthy lives. The geographical distribution of man, as well as the manner of life, also furnishes valuable evidence in this case. Travelers who have visited the polar regions, and pre-eminently Dr. Kane, give us undoubted testimony of the necessity of eating meat and animal fat to keep the body in health: since the low temperature not only requires a greater amount of combustive material, but this greater energy of respiration produces a more rapid w'aste of all the tissues of the body^ requiring a more abundant supply of azotised and non-azotised material to supply the deficiency. And on the other hand experience shows that in tropical climates stimu- lating food and drink should be avoided, because the high temperature of the atmosphere depresses vital energy, and consequently less material for supporting animal heat is re- quired with a corresponding decrease in the waste of the body. 324. Example of tlie Esquimaux. — As examples of these principles one traveler among the Esquimaux relates that these people relish very heartily tallow candles as a dessert for din- ner. Another states that he has seen the Greenlanders eat from twenty to thirty pounds of blubber, or whale-fat, at one meal. This, however, was a sufficiency of food to them for two or tliree days. Give the testimony of experience. Give the arj^nment derived from difference in climate. What kind of food is necessary to support life in polar, and what in tropical countries ? 324. State luxurious articles of diet among Esquimaux and Greenlanders. How much will a Greenlander sometimes cat? AND PHYSIOLOGY. 179 825. Voice of Chemistry —Chemistry, however, teaches us that we can find in the vegetable world all the principles necessary to support the body without using animal food. And although the vegetable kingdom contains those elements which will support life in many instances, yet we know, as a general riile^ that we find man in the highest degree of bodily and mental vigor, only when he makes use of a mixed diet. And we also find that all animals which are the most active in their habits, and rapid in their motions, are feeders upon animal flesh. There is also a race of half civil- ized savages, the Guanchos, who spend the greater part of their lives in the saddle and constantly in a state of great activity, who live almost exclusively upon animal diet, and yet are unequaled in their powers of physical endurance, and live lives fully equal to the average in duration. 326. Argument from the Teeth. — The strongest physio- logical argument in favor of a mixed diet, is found in the conformation of the teeth and alimejito^ canal of man. In those animals which live exclu^f^el^lipon animal, diet, the teeth are sharp and pointed, with a very short alimentary tube, since the nutrient portion of the food is readily absorbed by the lacteals. On the other hand, the teeth of vegetable feeding animals are smoothed upon their upper surfaces, being adapted to crush vegetable substances, and the alimentary tube very long, since the nutrient portion of vegetable, food is not so readily parted with. Now in man we ftid neither of these apparatuses perfectly complete, but an admixture of both. Part of the human teeth are of the carnivorous or flesh eating kind, and another part of the herbivorous or vegetable eating kind : but each of them so modified, that either kind of food can be readily prepared for digestion. The alimentary canal too is intermediate between that of the carnivorous and herbivorous type, being equally well adapted 325. What does chemistry teach on this subject? How does great bodily activity affect the diet as illustrated by the Guanchos ? 326. State the argument derived from the teeth, What two kinds of teeth are found in man ? 180 HITCHCOCK’S ANATOMY to the digestion of animal or vegetable food, or an admixture of both. 327. Conclusions. — The kind of food which is the most perfectly adapted to the constitution of man, seems to be de- termined by the following rules, based upon the temperature of the climate, the habits or employments of life, and the health of the individual. First. The lower the temperature the greater the amount of animal heat necessary for the support of life, which re- quires the fattest portions of the meat. Second. The more active the habits of the individual, and the greater the amount of exposure in the open air, the greater the demand for animal food. Third. If the system be suffering under inflammation of any sort, or if there be any tendency to inflammation, animal food should be used very sparingly, or entirely dispensed with. Fourth. That diet seems to be the most perfectly adapted to the human constitution in all climates and seasons, which is composed of animal and vegetable food in the proportion of one to two, or one third by weight of animal food to two thirds of vegetable food. This proportion is the basis of the diet scales of the United States and British Navies. 828. Use of the Lacteals. — The use of the Lacteals is to absorb the Chyle or nutrient material from the contents of the intestines, and .carry it into the general circulation. The force by which this fluid is taken from the alimentary canal, is by no means understood at present, unless it be capillary attraction. 329. The Chyle. — The Chyle is a white liquid somewhat thicker than milk, and is made up of a solution of albumen containing minute globules, or cells, which are mostly spher- 827. What four conclusions arc drawn from this whole subject of diet? 328. What is the function of the Lacteals? What is the force that circulates the Chyle? 829. De< scribe the Chyle. AND PHYSIOLOGY. 181 ical and about 3 o¥o ©th of an inch thick, and Chyle Cor- puscles, which are simple cells about e ©Voth of an inch in diameter. 330. The Place where the Chyle enters the Blood. — Principle of Venturi. — As already mentioned the Chyle en- ters the blood through the left Subclavian vein of the neck. It is not, however, simply by the opening of one vessel into another that this is accomplished, but advantage is taken of the union of two currents, so that by their combined force the chyle is drawn in towards the heart. The mouth of the Pig. 18t. Position of the Thoracic Duct and the Veins of the Neck where it emx>ties. S. V. Subclavian Vein. J. Jugular Vein. D. Thoracic Duct. Thoracic Duct, however, is provided with valves to prevent the blood from entering it, in case obstruction in the veins should occur. And it is a physical fact that, when a small tube is inserted perpendicularly into the lower side of a hori- zontal conical pipe, in which water is flowing from the nar- Give the size of the Chyle Corpuscles. 880. Give the description of the hydraulic principle by which the chyle is drawn towards the heart. 182 II ITCH cock’s anatomy Fig. 188. Illustration of the Principle of Ven- turi. When a current passes through a large tube, if another smaller tube open into its side, the current in this tube will be drawn into the large tube, even against the force of gravity. rower to the wider portion, if the vertical tube be made to dip into a vessel of water, not only will the water of the larger pipe not descend into the vessel, but it will draw up the water through the small tube so as to empty the vessel.’’ This is called “the principle of Venturi,” and is well illustrated by the entrance of the Thoracic Duct into the Subclavian vein, as seen in the cut No. 187. A diagram illustrating the same principle is seen in Fig. 188, the arrows representing the direction of the currents, and the smaller, perpendicular tube illustrating the Thoracic duct at its entrance between the veins of the neck. 331. The lymphatics. — The Lymphatics in general structure and function resemble the lacteals. The lacteals, however, are designed exclusively for promoting the growth of the body by adding nutrient materials, while the lympha- tics give up to the general circulation not only useful pro- ducts, but all those which are absorbed. Hence whatever is presented to the mouths of the lymphatics, is carried into the general system, while injurious products are not usually taken up by the lacteals. (See also page 284.) 332. The Action effected by the lymphatics. — Since the Lymphatics, as already described, are found in every Illustrate the principle of Venturi. 831. Give the general structure of the Lympha- tics. state the probable differences in function between these and the Lacteals. AND PHYSIOLOGY. 183 part of the body in great numbers, and are almost constantly at work in removing the waste particles, it follows that in process of time a large part, or even the whole of the body, will be removed. And it is generally admitted that the whole body is actually renewed every few years, although the precise number can not be stated, since so many circum- stances modify the change, such as exercise, the amount of food taken, and climate, as well as other causes not so easily understood. It is, however, quite probable that the period of ten years is sufficient to complete the change in most in- dividuals, and the number is stated by some as low as seven. HYGIENIC INFERENCES. 333. 1. From the structure and functions of the Digestive Organs we can derive some hints as to the manner of pre- venting acute and chronic diseases in them. 334. Danger of Eating too much— 2. We see that there is a great danger of eating too much. Large quantities of food distend the coats of the stomach, and give too much labor for them to perform. As a natural consequence the gastric glands are weakened from excessive action, and then indiges- tion or some other diseased action is sure to follow. And in how much better health wmld multitudes in the higher classes of society be kept, if some of the numerous dishes they use were omitted! And in this country the remark applies to nearly all classes. 335. We are apt to eat too many Kinds of Food. — 3. We also see that our meals are generally made up of too 7nany kinds of food. In the habits of the lower animals we dis- cover a great simplicity of diet. Even in those whose ana- tomical structure closely resembles that of man, the appetites 832. ITow jrreat changes are effected in the body by the Lymphatics? In what length of time is the body probably entirely renewed? 334. What is the injury from eating too much ? 335. What is said about eating too many kinds of food ? 184 HITCHCOCK’S ANATOMY are easily satisfied by the simplest food. Nor does man’s intellectual superiority demand a greater variety in diet, all that is requisite being the materials necessary to support the growth of the different tissues. 335a. 4. It is evident that condiments and spices shoidd he always used very sparinyhj^ and generally s])ices not at all. To be sure nature seems to indicate the want of a mode- rate supply of salt (perhaps for the juices of the stomach), but pepper, mustard, and ketchup excite the coats of the stomach to an action that is unnatural. And it seems to bo a law of the system that stimulants and opiates, if used regularly, must be constantly increased in quantity, other- wise they will lose their effect, and disorder will follow. In fine, all experience seems to prove that the demands of nature for food are very simple and easily gratified ; but the appetite may bo so trained as to loathe every thing of a simple and natural kind, and be satisfied only with the stimulating com- pounds of modern cookery. The law of nature, however, cannot be reversed, that he who lives in the simplest manner lives the longest, and suffers the least from pain or disease. 336. Wc must not eat too fast. — 5. Most persons eat too fast. No time is gained on the sum total of life, by taking any from that demanded by nature for eating and digesting food. A fortune or great reputation, it is true, may some- times be gained a little quicker by using the time which the stomach rightfully claims, yet the penalty for such robbery is a shorter life, or a disease which makes life miserable. 337. Tlie Time of Eating, — 6. We see that the time of eating should not encroach tipon the hours devoted to sleep ^ or those of hard labor. During sleep the brain needs quiet; but if there be any function going on such as that in the earlier stages of digestion, the brain, as a matter of necessity, Does intellectual superiority require so great a variety as is often introduced ? 335. Why are condiments ai»d spices to bo used very sparingly ? What are the demands of nature upon the appetite? IIow much may the appetite be perverted? 336. What danger in eating too fust? 337. What time during the day should wc eat? AND PHYSIOLOGY. 185 must labor till the process is accomplished, and as a result, dreams or imperfect trains of thought will produce that kind of sleep which cannot refresh the body. If again the time for meals precede or follow very closely upon hard labor, a law of nature is broken, and the penalty is sure to follow. The nervous energy cannot be immediately called off from the part to which it has for some time been directed (whether to the brain or the muscles), and consequently the stomach for a while must lie nearly inactive. Hence a short season of relaxation from all active exercise, whether mental or physical, just before and after meals, is very conducive to health, since in the former case the circulation is equalized, and the brain can prepare its energies to expend them on the stomach, while after meals the whole force of the nervous in- fluence is needed for a time by the digestive function before it can be directed to the muscles for exercise. Even a short time after dinner devoted to a nap promotes digestion quite rapidly, although the habit often is an inconvenient one, to say the least, since if by unavoidable circumstances it is omit- ted for once, the person feels uncomfortable the rest of the day. 838. Danger of employing Stimulants for weak Stom- achs. — 7. We see the error and danger of a very common practice : that whm the digestive organs become weak^ and the appetite is poor ^ stimulants are employed to waken the stomach to crave more food than it can digest. This only aggravates the difiiculty and makes a demand for stronger stimulants, and thus often is the system prematurely worn out. Whereas, would men follow nature and when a dimin- ished appetite teaches them to eat less and give the organs an opportunity to rest, they would ere long rally and digest all that is necessary to give tone and energy to the system. To Why should not hard labor and a full meal come closely together? How does a short nap after dinner affect digestion ? What is a serious objection to the habit? 338. What danger results from using stimulants to help weak stomachs ? Should we eat more than the natural appetite craves? 186 II I T C 11 C O CMC ’ S A X A T O M Y eat more than the stomach craves, is not the way to gain strength, but to increase weakness and shorten life. COMPARATIVE SPLANCHNOLOGY. 339. Digestive Organs of Mammals. — In many mam- mals the digestive organs in their general arrangement and construction resemble those of man. Fig. 189. Maxillary Gland. Trachea. Lungs. Heart. Liver. Gall Bladder. Colon. Caecum. Small Intestine. Parotid Gland. Pharynx. Gullet. Thorax. Midriff. Stomach. Pancreas. Soleen. Kidneys. Colon. Abdomen. Eectum. Bladder. Digestive Apparatus of an Ape. 340. Esophagus of the Horse, — In the Horse, however, at the lower end of the Esophagus, there is a sickle-shaped 340. How does tlio Esophagus of tho Horse differ from that of a man? AND PHYSIOLOGY. 187 fold of lining membrane, which makes it impossible for this animal to vomit. 341. Stomach of Ruminants. — Mammals, as a general rule, have very simple stomachs, and particularly those which live upon animal food. But in those herbivorous ones which chew the cud, this organ consists of four cavities, Fig. 190. Gullet. Esophiigean Groove. Mauiplies. Duodenum. Pylorus. The Eennet. 2d Stomach. Paunch. Stomach of the Sheep. the Ingluvies or ‘^Paunch,’’ the Reticulum or Honey Comb,’’ the Omasum or ‘^Many Plies,” and the Abomasum Fig. 191. Gullet. Esophageal Groove. Mauiplies, or Third Stomach. Eennet, or Fourth Stomach. Duodenum. Pylorus. Second Stomach. Paunch. Interior of Stomach of the Sheep. 341. What is the number of stomachs in herbivorous animals ? Give the names cf each. 188 HITCHCOCK’S ANATOMY or ^ Red/’ As tlio food enters tlio Inglu- vies, it is simply mixed with the fluid secreted by its coats, when it passes into the Reticu- lum, where it not only receives additional se- cretions, but is made into little ‘‘cuds” or “pellets,” which, when the animal is at rest, are returned to the mouth for the purpose of re-chewing and mix- ing with the saliva. After this process is completed, they are sent into the Omasum, which cavity seems designed to prepare the food to enter the fourth stom- ach where the true process of digestion takes place. And it is from this fourth stomach or Abomasum, that the Rennet is taken from young calves, and used by cheesemakers for the purpose of coagulating the milk. 342. Reason of this Complex Stomach. — The probable reason of such a complicated stomach in these animals is that since they have such poor means of self-defense, they need to crop their food as quickly as possible, and then retire to a safe place to masticate it. And it is also partly owing to the fact that vegetable substances require a longer process for di- gestion than does animal food. 343. Icnj^th of Intestine. — The length of the Intestine depends as a general rule upon the food used by the animal. Pig. 192. stomach of the Ox. A. Paunch. 7?. Re- ticulum. C. Omasum. D. Abomasum. E. Pylorus. F. Duodenum. G. Esopha- gus. Give tlie process of die wing the cud in these animals. 842. What is one important reason for this eoinplicated arrangement? 843. Upon what does the length of Intestine ilepeml ? AND PHTSIOLOGY. i89 the vegetable feeders having a long tube, and the flesh feeders a short one, since animal food is so easy of stomach digestion, and the nutrient portion of it so readily taken up by the lacteals. Thus the ox has an alimentary tube fifteen or twenty times the length of the body, amounting in a full grown animal to 150 feet, the sheep one twenty-eight times its length, while many of the carnivora exhibit one only about three times the length of the body. The true Cetacea or Whale tribe are the only ones which do not have a marked distinc- tion between the large and small intestine. 344. The liver, — The Liver as in man is one of the largest organs in the body, and is much more divided into lobes in carnivorous than herbivorous animals. It is smallest and least divided in those animals with compound or rumi- nating stomachs. 845. Bill of Birds. — Birds are destitute of teeth, since the process of mastication is carried on in a certain portion of the alimentary canal. But the horny investment of the jaws known as the bill, is harder in birds of prey, and those Fiq, 193 , Os Ilyoidcs. Head of the Woodpecker. that feed on fruit and nuts, as Parrots, and in Woodpeckers. The bill, or rather mouth, of Ducks and Geese is lined by a tender membrane, in order that they may be partially What is the length of the Intestine of the Ox? Of the Sheep? Give the propor- tional length of Intestine in Carnivorous Animals. 344. What difference in the Liver between flesh and herbivorous animals ? 345. Why are Birds destitute of teeth ? What Birds have the hardest bills? What peculiarity in the lining membrane of the mouth of Ducks, etc. ? 190 HITCHCOCK’S ANATOMY FiO. 194. Digestive Apparatus of Fowl. a. Esophagus, h. Crop or Ingluvies. c. Pro- ventriculus. d. Gizzard, e. Liver. /. Gall-Bladder, g. Pancreas, h. Duodenum. i. Small Intestine. k. Cteca. 1. Large Intestine, m. Ureter, n. Oviduct. o. Cloaca. guided in the selection of their food from the soft mud by the sense of touch. 34G. Stomach of Birds. — The Gizzard. — The true stomach of birds consists of two divisions. There are, how- 84G. State the usual number of stomachs in Birds. AND PHYSIOLOGY, 191 ever, three enlargements of the alimentary canal, all of which prepare the food for assimilation. The first of these is the ‘‘ Ingluvies’^ or ‘‘Crop,’’ where the food is softened by the mucous secretion of the lining membrane. Then as it passes along into the “ Proventriculus,” it receives the gastric juice from the gastric glands which line it. The second stomach, the “Gizzard,’" is round and flat and made up of powerful muscular fibres, except in birds of prey, where it is thinner in texture. In gallinaceous birds its lining membrane is of a horny consistency, which, with the powerful muscular fibres, render it an organ of mastication to granivorous birds. Gravel and angular stones are purposely swallowed by these birds to aid in the digestive or grinding process. 847. Teeth and Jaws of Reptiles —Eeptiles need teeth only to seize and retain their prey, since whatever food is taken by them, is swallowed without mastication, which is one reason why the jaws and throats of serpents are so very capacious. A peculi- arity in their bony construc- tion renders this possible, for the jaw is not made up of one or at most two pieces as in mammals, but of several segments, which rea- dily move one upon another, as if with different articula- tions. 348. The Tongue. — The Tongue is used as an instrument for the capture of prey by many reptiles. Frogs and Sala- manders are able to thrust it out with great rapidity and Give the names of each. Describe the Gizzard. Why are caravel and stones swallowed by granivorous birds? Which is the true stomach ? 847. What is the only use of teeth in reptiles? State the reason why the jaws are so capacious. Of how many bones are they frequently made up ? 348. Of what use is the tongue to some reptiles? 9 FiG. 195. It ma mi Head of the Kattlesnake. mi. Lower Jaw. t. Tympanic Bone, ma. Mastoid Bone, m. Upper Jaw, 102 HITCHCOCK’S anatomy coil it upon insects or any other object. This property, to- gether with the adhesive mucus found upon it, makes it for these animals a very serviceable apparatus in obtaining food. 349. Esophageal Tcclli. — In many animals of this de- scription the Esophagus is lined with bony processes pointing downwards, called Esophageal teeth, which greatly aid in swallowing the large masses which they are accustomed to force into their stomachs. 850. Stomach. — length of Intcsliiie. — The Stomach seems to be only a dilatation of the Intestine. In many species it is divided into two cavities resembling those of a bird, (Fig. 196) : the first a Gizzard, or an organ made up of stout muscular fibers, and the second a thin walled and secreting cavity. In Crocodiles it is round, and the muscular coat is very thick, in order to reduce to a digestible size the coarse food which it so greedily devours. The length of the intestine in most reptiles is about twice the length of the body ; in Lizards, however, it is only about the same length as the body. A cloaca or additional rectum is sometimes found in these animals, as is the case among birds. 351. Stomach and Intestine of Fishes — In many Fishes the intestinal tube extends from the mouth directly through the animal without any enlargement for the stomach, or any convolutions, as is the case with all the animals thus far con- sidered on this subject, and with which no organ of secretion is connected, except the liver. The intestinal canal, however, is generally more or less convoluted, and ordinarily it is short. In the Shark the stomach is parceled out by constrictions and With wliat is it covt'red, that renders it more serviceable as an instrument of capture ? 849. What is said of Esophageal teetli? 850. Is the stomach a simple or complex cav- ity ? What is the uvuragi; length of intestine among reptiles ? What is said of a cloaca? 851. In what condition is tlio stomach found in mostlishos? What peculiarity is met ■within the Shark ? ' I AND PHYSIOLOGY. 193 Fig. 196. Intestine, cl. Cloaca. /. Liver, o. Ovary, o'. Eggs. t. Trachea, p. p'. Lungs, vt. Ventricle, e. e'. Auricles, a. ad. a'. Aorta, ac. Carotid Arteries. ve. Vena? Cavje. vp. Pulmonary Vein. inversions into several divisions with valve-like appendages between them. 852. liver. — Fishes have usually a large soft Liver com- pletely saturated with an oil. Its form is various, but is C52. Speak of the Liver of fishes. 194 HITCHCOCK’S ANATOI^rY often imperfectly divided into two lobes. The oil that is ex- pressed from the liver of the Cod Fish, is often used with great efficacy in the early stages or symptoms of consumption. Fig. 197 . 353. Pyloric Appendages. — In many fishes with bony skeletons there is found a cu- rious set of gland-like organs called Pyloric appendages. They vary in number from two in the Plaice, to two hundred in the Mackerel, and always cither encircle the pylorus, or are found near the upper end of the intestine. These appendages are inva- riably absent in those fishes which have an imperfectly formed stomach, and by some are considered as analogous to a Pancreas in function. 354. Salivary Glands. — Salivary Glands are wanting in fishes, but their place is supplied by an increased de- velopment of the mucous glands of the mouth. 855. Digestive Organs in the Invertebrates.— In the Polyps of the Radiate ani- mals, we have the simplest form of digestive apparatus, viz., a simple sack, with a mouth to receive the food and to disgorge the refuse, as is seen in Fig. 198, A. Other Polyps, however, have two openings in their stomach or sack, as shown in Fig. 198, B. Digestive Appunitus of a Beetle, a. Head. h. Crop and Gizzard, c. Biliary Vessels. (J. Intestine, e. Secreting Or- gans. AND PHYSIOLOGY, 195 Fig. 198 . A Digestive Apparatus of Unicellular Animals. 356. The Hydra. — Fig. 199, an unicellular animal, is an example where the simplest sort of digestive organs is ex- hibited. The animal is little else than a gelatinous sac, and if it be turned inside out digestion will still go on. Thus, ‘’notwithstanding the simplicity of its structure, this creature feeds not merely upon algae, but upon young active animalcules, the young of crustaceans, etc. ; any one of these, when they happen to came in contact with one of the tentacular filaments, be- ing usually retained by adhesion to it. As this filament shortens itself, all . . Hydra or Fresh Water Polyp, a. En- the surviving filaments ap- trance and Exit to stomach. ply themselves to this captive particle, so that it becomes gradually inclosed, and grad- 356. What is the process of digestion in the hydra ? 196 HITCHCOCK’S ANATOMY ually shortening, so as at last to bring the prey close to the surface of the body. The spot with which it is brought in contact, then slowly retracts, and forms at first a shallow de- pression, gradually becoming deeper and deeper, into which the prey sinks little by little, for some time, however, con- tinuing to project from the surface. The depression at last assumes a flask-like form, by the drawing in of its margin, and finally its edges close together, and its prey is entirely shut in. This gradually passes to the center of the body, where its soluble parts are dissolved, whilst in the mean time its external portion recovers its pristine condition.” 357. Other Radiates have an alimentary canal more com- plicated, having a stomach and csecal appendages that appear to perform the oflSce of a liver. Some of the Echinoderms have teeth; in the Echinidm is a curious apparatus in the mouth called Aristotle’s lantern. 358. Another form of the digestive apparatus consists of a central cavity, wdth branches extending through every part of the body. . Fig. 200 shows this in one of the Articulated animals, an Arachnoid Crustacean, the Ammothea pycnog- onoides. This arrangement is found in several other classes of the Invertebrates. 359. The Crustaceans are generally furnished with two upper jaws, called Mandibles, which move laterally ; and be- hind these, two pairs of weaker and softer lower jaws, which are sometimes changed into suckers and legs. The higher branches are always provided with prehensile organs for seiz- ing the food, which are arranged in pairs. 360. These are best seen in the Lobster, where they are enormously developed, projecting in front of the eyes a dis- tance nearly equal to that of the length of the whole body, and each extremity is furnished with a powerful pair of pincers. Some of the higher Crustaceans have a sort of horny teeth implanted in the coats of the stomach which are worked by a 359. What are the jaws of crustaceans? AND PHYSIOLOGY. 197 Fig. 200. Digestive Organs of Ammotlica pycnogonoides (Crustacean), a. Esophagur h. Stom« ach. c. Intestine, d. Digestive Cavity of the Jaws. e. Digestive Cavity of the Legs. powerful set of muscles, which help in the reduction of the food. These teeth are found in the Lobster’s stomach. The stomach of the Leech is very capacious, being nearly the size of the whole body. The same is essentially true of the com- mon Earthworm, which is an Annelid. In many insects salivary glands are present, and in such cases they are placed at the commencement of the alimentary canal. The different parts of the alimentary canal in insects ^‘may be properly distinguished in the following manner. The first portion is the Esophagus, muscular, occupying the three thoracic seg- ments and often dilated at its posterior part into a crop (Ingluvies) and muscular gizzard (Proventriculus). Some- times there is appended to the Esophagus a sucking stomach, 198 HITCHCOCK’S ANATOMY Fia. 201. Aplysia (Mollusc) laid open to show the viscera, a. Esophagus, c. Salivary Glands. ^/. Cephalic Ganglion, e. Esoidiageal Ganglion, First Stomach or Crop. A. Third or Tnio Stomach, i. (Jizzard. Jc. Intestine. Liver, Posterior Ganglion, w. Aorta. o. Hepatic Artery. 7?. Ventricle of Heart, q. Auricle, n a. Branchiae or Gills, v. Lower Intestines, v. Ovary. AND PHYSIOLOGY. 199 consisting of a more or less pedunculated thin walled vesicle, which is multiplicated on itself when empty. The second portion consists of a stomach (ventriculus) in which the chyle is formed, and which is continuous at the point of insertion of the malpighian vessels with the third portion of the digest- ive canal. This third portion commences by a small and usu- ally short ileum, which is followed by a colon larger and of variable length. This last often has a caecum at its anterior extremity, and terminates posteriorly in a short, muscular Rectum.'^ considerable number of insects take no food during their perfect state, the object of their existence being only to accomplish the act of reproduction. Their jaws are often very rudimentary, and are fit neither for sucking nor for masticating.’’ 361. The Annelida have sometimes quite complicated jaws, even as many as eight or nine, moving laterally. They have also salivary and hepatic glands, as have many other invertebrates. These are shown on Fig. 197, which repre- sents the whole alimentary canal of an insect. 362. The Cephalopod Mollnscs have a mouth, two horny jaws moving vertically in the pharynx, a tongue, an oeso- phagus, a stomach, a pylorus, and an intestinal canal. 363. In the Cephalophora the jaws move laterally for the most part. In the whole class we find a biliary apparatus and generally salivary glands. Fig. 201 shows the digestive organs of a Gasteropod, the Aplysia. Nearly all the Ceph- alophora have a longer or shorter fleshy mass attached to the base of the pharynx that is comparable to a tongue. It has a longitudinal grove in it, and is sometimes included in a sheath. It is always covered with horny denticulated plates and spines, which are very delicate, and arranged in quite elegant longitudinal and transverse rows. The points of these spines turn backward, which aids greatly in swallowing. 200 HITCHCOCK’S ANATOMY 3G4. In some families of the Eiitozoa — the Cyslici, the Cestoclcs and A c a ii t li o c e p li a I i — there is no mouth nor pro{)cr intestinal canal, but there are vessels for the circulation of nourishment which is received directly through the sides of the body, on the principle of endosmosis. CHAPTER FOURTH. THE CIRCULATING SYSTEM.— ANGIOLOGY, OR HISTORY OF THE ORGANS OF BLOOD CIRCULATION. DEFINITIONS AND DESCRIP T^ONS. 365. The Circulatory Organs. this system are the Heart, Arteries, Veins, and Capil- laries, and are mainly tubes of various diameters and a hollow organ, with the double office of receiving and propel- ling the blood. 366. The Heart. — The Heart, or central engine of circulation, is located in the thorax or chest, resting by its lower surface on the dia- phragm, and somewhat to the left of the middle line of the body. It is of a conical form, made of animal muscular fiber, the fibers crossing themselves in at least three directions ; and it is a sin 2 ;ular fact that •The organs composing Fig. 202. An Anterior view of the Heart in a Ver- tical Position, with its Vessels injected. 1, Eight Auricle. 2, Left Auricle. 3, Eight Ventricle. 4, Left Ventricle. 5, Descend- ing Vena Cava. 6, Aorta. 7, Left Pulmo- nary Artery. 8, The Arteria Innominata. 9, Left Primitive Carotid. 10, Left Sub- Clavian Artery. 11, Anterior Cardiac Ves- sels in the Vertical Fissure. 12, Posterior Vessels from the Transverse Fissure. 13, Main Trunk of the Pulmonary Artery. 365. What are the organs used for the circulation of the blood ? 366. Give the location of the Heart. 202 HITCHCOCK’S A N A T O Y many of the fibers of the heart anastomose, or join ^vith each other in many places, as is seen in Fig. 203. The heart is a double organ, one side being called the arterial and the other the venous, or left and right hearts, since the for- mer receives and propels the pure or arterial blood, while Anastomosing Fibers of the Human Heart. the latter cirCulatCS VenOUS blood. Again, each of the two sides or hearts are divided into an auricle and a ventricle. Each of these four cavities will ordinarily contain about three fluid ounces, making the whole heart to contain nearly a pint. 367. The Auricles and Veiilriclcs.— The Auricles are the uppermost cavities of the heart, and are somewhat smaller Fig. 204. Xij ao t ac vj Artery of the Arm. Vein of the Arm. Left Lung. od VC vd a vg Lungs, Heart, and Principal Vessels in Man. or7, Eight Auricle, vd^ Eight Ventricle. vg^ Left Ventricle, a, Aorta, ac, Carotid Arteries. vc\ Vena Cava, t, Trachea, -rj. Jugular Veins. What are its shape, size, and four cavities called? What is the capacity of an adult heart ? AND PHYSIOLOGY. 203 than the Ventricles, or lower ones. The auricles also have the thinnest walls, and are capable of considerable dilatation, since by a sudden effort of the body the blood is liable to be sent in great quantities to the heart, and the veins would be in danger of rupture were there no elasticity in the receptacle. The thickened walls of the venti icles give increased power of Fig. 205. Vena Cava Sup. Art. Pulm. Aorta. Art. Pulm. Pulmonary Veins. Eight Auricle. • — Tricuspid Valve. ** — V ena Cava Inferior. / Eight Ventricle. ** i i , Septum. Aorta. Theoretical Section of the Heart in Man. contraction. This is needed because the ventricles drive the blood from the heart, and the auricles receive it on its return. The right ventricle, however, propels the blood only to the lungs, while the left ventricle sends it to all parts of the body except the lungs. The left auricle receives only the blood from the lungs, while the right auricle receives it from all the other parts of the body. 368. Valves of the Heart. — Between the auricles and ven- tricles are peculiar forms of muscular and tendinous fibers, resembling cords and pillars, that are termed valves, making a sort of curtain to allow the flow of blood from the auricles to the ventricles, but not in the opposite direction. At the 36T. Give the essential differences between the auricles and ventricles. Why does the left ventricle need the thickest walls ? 868. Describe the valves which lie between the auricles and ventricles. 204 II I T c n c o c i: ’ s a n a t o ?.r y point where the arterie3 arc given ofT from each ventricle are found (in each) three crescent-shaped folds of semi- cartilaginous tissue called Semi-lunar Valves, to allow the motion of blood in an outward direction, but to prevent the return, which is called regurgita- tion. 369. Pericardium. — In addition to the fasciae and fatty matter which im- mediately invest the heart, this organ is enclosed in another mem- brane in the form of a shut sac, a fibro-serous membrane called Fig. 207. Semi-lunar Valves of the Aorta laid open, a, Corpus Arantii on the Free Border. &, Attached Border, c, Orifices of Coronary Arteries. the Pericardium (meaning about the heart). This contains a small quantity of a fluid like water, so that the heart actually floats in a liquid, and does not rest firmly upon any hard sur- face. The pericardium not only exists as a loose sac about the heart, but it is reflected upon it where the vessels are given off ; covering it in the same manner as the fasciae cover and protect the muscles. 370. Arteries — Their Coats. — The Arteries are tough and cylindrical tubes which convey the blood from the heart to the different parts of the body. They are made up of three mem- Describo the Sorni-lunar V:ilvos find their locntion. 8G9. What is the sac called that surrounds the heart ? What fluid docs it contain? llow much of it is there? Is the jiericardium attached at all to the heart? 870. Of how many coats arc the arteries com- posed ? Fig. 206. Semi-lunar Valves of the Heart closed. AND rilYSIOLOGY. Fia. 208 . 205 Temporal Artery. Art. Pediosa. Vertebral Artery. Subclavian Artery. Peroneal Artery. Arterial System in Man. branes, of 'which the middle one deserves especial attention. This is an elastic coat composed of yellow fibrous tissue (Fig. 209), in order, as we shall presently see, to aid in the circu- Describe each one and tbeir peculiar value. 20G HITCHCOCK’S ANATOMY lation of tho blood. The inner one is smooth and of a serous charac- ter, for the ready pas- sage of tho blood over it. The arteries (all above ^V^h inch in diameter) are nourished by a capillary net-work which is made from ad- joining blood-vessels. Nerves are distributed to some arteries, but ordinarily they only accompany- them. 371. The Aorta. — The arteries sent to every portion of the body from the left ventricle proceed from one trunk, called the Aorta, meaning a starting-point. It is nearly an inch in diameter, and ascends in a perpendicular direction for about two inches, when it makes a curve upon itself, and descends through the thorax and abdomen until it reaches the fourth lumbar vertebra, when, as is the case with most of the large arteries, it divides into two branches of equal size. Between the curve or arch of the aorta and the heart no branches are given off, but from the summit of this arch to the subdivision in the abdomen a great number of branches are distributed to the different portions of the chest and ab- domen. 372. Description of Particular Arteries — Innominata — Carotid — Subclavian — Axi Ilary — Brachial — Ulnar Ra- dial — Palmar Arch. — The first branch arising from the sum- mit of the aortic arch is the large one called the Innomi- nata, or nameless artery. Next comes the Carotid, and both distribute themselves to the head and upper extremities. Fig. 209. Highly Magnified Portion of the Middle Coat of the Arteries. 871. Wliat is the Aorta? . Wliat docs tho word aorta mean? Give its course till it subdivides. Where does it divide into tho common iliacs? 872. Where are tho In- nominata Arteries? Tho Carotid? AND PHYSIOLOGY. 207 Fia. 210. A View of the Heart, with the Great Vessels of the Neck in Situ. 1, Eight Ventricle of the Heart. 2, Right Auricle. 8, Left Ventricle. 4, Left Auricle. 5, Pulmonary Artery. 6, Arch of the Aorta. 7, Descending Vena Cava at its entrance into the Eight Auricle. 8, Ascending Vena Cava. 9, Thoracic Aorta. 10, Arteria Innominata. 11, Eight Brachio-Cephalic Vein. 12, Left Brachio-Cephalic Vein. 13. Section of the Sub- Clavian Artery. 14, Section of the Siib-Clavian Vein. 15, 15, Primitive Carotid Ar- teries. 16, 16, Internal Jugular Veins. 17, 17, External Jugular Veins. Between these Veins is seen the Section of the Sterno-Cleido-Mastoid Muscle. 18, The Trunk formed by the Superficial Cervical Veins, known sometimes as the Anterior Jugular Vein. 19, A Branch from it to the Facial. 20, Main Trunk from the Inferior Thy- roid Veins. 21, Superior Thyroid Vein. 22, Transverse Cervical Artery and Vein. 23, Lingual Artery and Vein. 24, Facial Artery and Vein. The Innominata on the right very soon becomes the Sub- clavian, after which the corresponding arteries of both arms receive the same name. The Sub-clavian Artery, as its ety- mology implies, lies directly beneath the clavicle until it reaches the axilla, or arm-pit, where it receives the name of The Sub-clavian ? The Axillary ? 208 II I T C II<; O C K ’ S A N A T O Y r Fia. 211 . A Yiew of the Arteries of the Neck and Shoulder. 1, Primitive Carotid Artery. 2, Internal Carotid Artery. 8, External Carotid Artery. 4, The Superior Thyroid Artery. 5, Branches to the Muscles. 6, Main Branch to the Gland. 7, Inferior Pharyngeal Ar- tery. 8, Lingual Artery. 1), Facial Artery. 10, Its Branches to the Sub-Maxillary Gland. 11, Sub-Mental Branch. 12, Principal Branch of the Facial as it goes over tlic Jaw. 13, Occipital Artery. 14, Branches to the Muscles on the Back of the Neck. 15, Main Trunk to the Occiput. 16, Posterior Auricular Artery. 17, A Branch cut otf, which goes to the Parotid Gland. IS, Origin of the Internal Maxillary Artery. 19, Origin of the Temporal Artery. 20, Origin of the Anterior Auricular. 21, The Sub-CIavian. 22, Origin of the Internal Mammary. 23, Trunk of the Inferior Tliyroid, from which arise in this subject the Anterior and Posterior Cervical Arteries. 24, Branch of the Inferior Thyroid going to the Thyroid Gland. 25, Anterior Cervical going up the Neck. 26, Posterior or Transverse Cervical. 27, Branches to the Scaleni and Levator Scapulaa Muscles. 28, The Superior Scapular Artery. 29, The Thoracica Superior of the Axil- lary Artery. 30, A Branch to the Deltoid. 81, Eecurrent Branches of the Intercostals. Axillary Artery. Then as it passes along the inner side of the humerus it is called the Brachial, until it has passed be- yond the inner side of the elboAV, where it is divided into the Ulnar and lladial, corresponding in position and direction to Where are the Brachial, Ulnar, and lladial Arteries ? AND PHYSIOLOGY. 209 the ulna and radius. Some- times, however, the branch- ing takes place higher up, as is seen in cut 212. When these have fairly passed the wrist, they both join again in an artery which describes a curve at the base of the meta- carpus crossing the palm of the hand, and called the Pal- mar Arch. Small branches are given off from this which supply the different parts of the hand, including the fin- gers and thumb. 373. Distribution of the Carotids — Vertebral — Circle of Willis. — The common Ca- rotid Arteries, one on each side of the neck, pass upwards from the innominata and sub- clavian nearly as far as the angle of the jaw, when they divide into the internal and external carotids, the latter furnishing blood to the face, and the former to the brain and back part of the head. The Vertebral Artery is also giv- en off from the sub-clavian, which, passing backward, en- ters the spinal column at the sixth cervical vertebra, and Deep-Seated Palmar Arch. Fig. 212. Arteries of the Arm. 1, Termination of the Axillary Artery. 2, The Brachial Ar- tery. 3, 3, Radial Artery, 4, 4, Ulnar Ar- tery. 5, A Recurrent Branch. 6, Anterior Interosseous Artery. 7, Superficial Pal- mar Arch formed by the Ulnar Artery. 8, 9, The Anastomosis of the two Arteries, much enlarged. What is the Palmar Arch ? 373. Give the branches of the Carotid as it passes up- ward to the head. P (B 210 HITCHCOCK’S ANATOMY passing through a foramen or opening in the transverse process of each of these vertebrae, at last reaches the posterior portion of the brain. This artery in the brain meets with the termi- nal branches of the internal carotid, so that the blood can easily reach the brain from either direction. By this ar- rangement, if, from pressure or accident, the flow of blood to the brain in either of these channels should be obstructed, the other would supply it; for sensation and consciousness Fig. 213. Circle of Willis. 1, Vertebral Arteries. 2, 3, Anterior and Posterior Spinal Arteries. 4, Posterior Meningeal Artery. 5, Inferior Cerebellar. 6, Basilar. 7, Superior Cerebel- lar. 8, Posterior Cerebral. 9, Branch of Carotid. 10, Internal Carotid. 11, Ophthalmic Artery. 12,13, Cerebral Arteries. 14, Anterior Communicating Artery. entirely cease if the brain be deprived of its arterial blood. This arrangement is called the “ Circle of Willis’’ from its discoverer. What arteries does the Vertebral communicate with iu the brain? What is the ser- vice of this arrangement? AND PHYSIOLOGY. 211 874. Thoracic Aorta— Abdominal Aorta — Coeliac Axis — Gastric, Hepatic, Splenic, Renal, Mesenteric, and lum- bar Arteries. — After the aorta fairly commences its descent — called the Thoracic Aorta — several small branches are given oflf from it which send nourishment to the heart and lungs, and next a pair which are distributed to the diaphragm. Then Fig. 214. ^ / A View of the Abdominal Aorta and its Branches. 1, 1, The Diaphragm. 2, Foramen Quadratum and Section of the Ascending Vena Cava. 3, Foramen Esophageum and Section of the Esophagus. 4. Foramen Aorticnm in the Crura of the Diaphragm. The Phrenic arteries are seen going to the Diaphragm. 5, CapsulsE Eenales. 6, The Kid- neys. 7, Abdominal Aorta. 8, Phrenic Arteries. 9, Ccelic — giving off. 10, The Sple- nic. 11, The Gastric. 12, The Hepatic. 13, Section of Superior Mesenteric. 14, Emul- gent Arteries. 15. Spermatic Arteries. 16, Inferior Mesenteric. 17, 17, Lumbar Arteries. 18, Division of the Abdominal Aorta. 19, Its last Branch — the Middle Sacral. 20, Primitive Iliacs. 21, Ureters — in their Position to the Arteries. 22, Internal Iliacs. 23, External Iliacs. 24, Circurnflexa II ii. 25, Distribution of the Epigastric. 26, Blad- der distended with Urine. The Vesical Arteries are seen near it. 374. What are the first branches of the Thoracic Aorta ? 212 HITCHCOCK’S ANATO:\IY Fm. 215. A Front View of the Femoral Artery, as irell as of the External and Primitive we meet with a large trunk given off just below the dia- phragm, about half an inch in length, called the Coeliac Axis, which gives origin to the Gastric artery supplying the stomach, the Hepatic, running to the liver, and the Splenic furnishing blood for the spleen. Below this we find the Renal arteries, sup- plying the kidneys, and the Superior and Inferior Mesen- teric Arteries, wdiich give blood to the intest’nes, and the Lumbar Arteries, terminating in the external muscles of the abdomen. 375. Iliac Arteries — Fe- moral, Popliteal, and Tib- ial Arteries— Dorsalis Pe- dis. — As already mentioned, the aorta divides into two branches opposite the fourth lumbar vertebra, for the supply of the lower extrem- IliacsofthePwiglit Side. 1, Primitive Iliac Artery. 2, Internal Iliac Artery. 3, Exter- nal Iliac Artery. 4, Epigastric Artery. 5, Circumflexa Ilii Artery. 6, Arteria Ad Cu- tern Abdominis, 7, Commencement of the Femoral just under the Crural Arch. 8, Point where it passes the Vastus Internus Muscle. 9, Point where it leaves the Front of the Thigh to become Popliteal. 10, Muscular Branch to the Psoas and Iliacus. 11, External Pu.lic Artery cut olf. 12, Origin of the Internal Circumflex. 13, Profunda Fc- moris. 1 1. Muscular Branch. 15, 16, Artery to the Vastus Externus Muscle. 17, Artery to tlio Pcctincus and Adductors. 18, First Perforating Artery. 19, 19, Muscular Ar- teries. 20, 21, Anastomotica. 22, Superior External Articular. 28, Middle Articular. 24, Inferior External Articular. 25, Inferior Internal Articular. Describe the Coeliac Axis. Where are the Gastric, Hepatic, Splenic, Penal, and Lum- bar Arteries ? AND PHYSIOLOGY. ities. These are the com- mon iliacs, from being near the ilium, and each of them soon subdivides into the Ex- ternal and Internal Iliac, the former of which supplies the greater portion of the leg with blood. As soon as it passes over the pubis it be- comes the Femoral Arterj, which at first is quite exter- nal, lying just beneath the skin and upon the pubis ; but as it passes down the femur it plunges deeper and deeper into the soft parts until it appears behind the knee, where it re- ceives the name of the Pop- liteal Artery. This is only a few inches in length, and at the upper extremity of the tibia divides into the Anterior and Posterior Tibial Arteries. The former runs along the inner side of the tibia and over the tarsal bones, until it reaches the metatarsus, when it becomes the Dorsalis Pedis, which gives off branches to Fig. 216 . A View of the Arteries on the Back of the Leg. The Muscles have been removed so as to display the Vessels in their whole length. 1, The Popliteal Artery, cut olf so as to show the Articular Arteries. 2» Lower End of the same Artery on the Popliteus Muscle. 3, Point of Bifurcation into the Posterior Tibial and Peroneal. 4, Superior Internal Articular Artery. 5, Superior Ex- ternal Articular Artery. 6, Middle Articular Artery. 7, Inferior Internal Articular Ar- tery. 8, Inferior External Articular Artery. 9, Branch to the Head of the Soleus Mus- cle. 10, Origin of the Anterior Tibial Artery. 11, Origin of the Posterior Tibial Artery. 12, Point where it passes behind the Annular Ligament to become the Plantar. 13, 14, 15, Muscular Branches. 16, Origin of the Peroneal Artery. 17, 17, Muscular Branches. IS, IS, Anastomosis of the Posterior Tibial and Peroneal Arteries near the Heel. 19, Muscular Branch from the Anterior Tibial. B75. What do tho common Iliac Arteries become as soon as they cross the- pubis? Give the location of the Femoral, Popliteal, Tibial, and Dorsalis Pedis Artery. 214 HITCHCOCK’S ANATOlSfY each of the toes, and suj)plies the upper part of the foot with blood. The Posterior Tibial Artery follows upon the back side of the leg a corresponding course to the anterior tibial, and supplies the sole of the foot and toes with blood. 376. Capillaries. — The arteries just described area few only of the principal ones, since at nearly every inch of their course larger or smaller vessels are given off according to the Fig. 211. Varieties of Capillaries. A, Tlioso around Fat Cells, b, In Muscle, c, In Mucous Membrane, d, Skin of Finger. nature of the part to be supplied with blood, and, with a few exceptions, such as the one in the head (circle of Willis), they all terminate in minute vessels called Capillaries. 377. Diameter of Capillaries — Functions Performed in them. — These are minute tubes j^oth to ^oVoth of an inch in diameter, and are always the terminations of arteries. Tlicy arc of a uniform size, and very regular in the distribu- J37G. How do nearly iiil tlio arteries terminate? Where is the only exception ? 877, Btuto the diameter of the Capillaries. What of their uniformity ? AND PHYSIOLOGY. 215 Fig. 218. A Front View of the relative Positions of the Veins anrl Arteries of the Face and Neck. On the Right side the Superficial Vessels are seen, and the Deep-seated ones on the Left. 1, Primitive Carotid Arteries. 2, Superior Thjuoid Arteries. 8, Internal Jugular Veins. 4, External Jugular Veins. 5, A Branch known as the Anterior Jugular Vein. 6, Supe- perior Thyroid Veins. T, Facial Arteries. 8, Facial Veins. 9, Zygomatic Branch of the Facial Artery. 10, Nasal Branch of the Facial Vein. 11, Anastomosis of the Facial Artery and Vein with the Ophthalmic Artery. 12, Venous Arch above the Nose. 13, Frontal Vein. 14, Temporal Vein. 15, Temporal Artery. 16, Frontal Branches of the Temporal Artery and Vein. 17, Infra-Orbitar Vessels. 18, Sub-Aponeurotic Branch of the Temporal Vein. 19, 20, Venous Anastomosis around the Eye-Lids. 21, Frontal Branches of the Ophthalmic Vessels of Willis. 10 21G ir I T C II C O C K ’ S A N A T O Af Y Fig, 219, tion of their branches, without any increase in tlicir diam- eter. The only exception to this is where red blood is not re- quired for the nourishment of the parts ; as in the white of the eye, the finger nails, the tendons, etc., where the ca- pillaries arc too small to allow the corpuscles of blood to pass througli them. And yet in many of the capillaries we find their size to be so small that the corpuscles could not, if unyielding, pass through. But this is readily accom- plished in most cases by the flexibility of the corpuscle, which permits itself to bo doubled up to such an extent that it will easily pass through a tube much smaller than its normal diameter. In the ca- pillaries the important pro- cesses of secretion, nutrition, and the production of a por- tion of animal heat take place ; so that there is no place in the whole body ex(3ept the A View of the Veins of the Trunk and outer COat of the eye, the ten- The Left Vena Innorninata. 8, The Riirht donS, the nails, and whlte Vena Innoininata. 4, The Ri^iht Buh-Cla- portions of the bodv gencr- vian Vein. 5, The Internal Jugular Vein. ^ ^ , 6, The External Jui^ular. 7, The Anterior ttHy wllCre true CapillariCS are Jisular 8 Tl.c Intoior Vona Cuva. 9 ^Ot found. The External Iliac Venn. 10, The Internal Iliac Vein. 11, The I’riniitivc Iliac Veins. 12, 12, Lurnhar Veins. 18, The Ki;,dit Spermatic Vein. 14, The Left Spermatic Vein. 15, The liiirht Emnlixent Vein. 10, The Trunk of the Hepatic Veins. 17, The Vena Azy- pos. 18, The llemi-Azypns. 10, A Uraneli communicatimr with the Left Renal Vein. 20, The Termination of the llemi-Azypos in the Vena Azygos. 21, The Superior Inter- Costal Vein. Where are true eapillaric.s not found? What takes place in them? AND PHYSIOLOGY. 217 Fig. 220. 878. The Veins — Their Coats— Their Yoliime, — The Veins carry the blood from all parts of the body to the heart. Like the arteries, they have three coats, and the larger veins follow the same general course as the large arteries. The sm.aller veins, however, are much more numerous than the smaller ar- teries, and are most abundant just beneath the skin. The whole volume of the veins may be regarded as a large cone, with the base at the surface of the body nnd the apex at the heart, so that in these vessels the blood is continually flowing faster and faster, in consequence of the fluid coming into a larger channel from small extremities, while the reverse hap- pens in the arteries. The veins are much thinner in struc- ture than the arteries, so that after death they most usually collapse. (See Fig. 218, p. 215.) 379. location of the larg- er Veins — Sinuses. — As al- ready mentioned, the larger veins usually lie near the larger arteries. Both also frequently have the same names. But there are sev- eral remarkable exceptions to this, as in the vessels of the brain. Here are but few veins, but several sinuses or channels. These are canals excavated in the dura mater of the brain with this mem- brane for an outer coat, and the serous layer of the true veins for an inner coat. These sinnses of the Base of the skuii. i, run in difierent directions on ophthalmic Veins 2 , Ca^^^mous Sinus. 3, Circular. 4, 6, Inferior Petrosal. 5, 9, the inside of the skull, and occipital Sinuses. 7, Internal Jugular Vein. 373. What course does the blood take in the veins ? Give the coa:s of the veins. What is the relative proportion of small veins and small arteries? What is said of their aggregate volume? 879. Where are the larger veins usually found ? What are Sinuses, and where are they found ? 218 HITCHCOCK’S ANATO>rY most of them empty into the great veins of the neck. Their probable service is to afford a free passage of blood from the brain, even if by excess of arterial action this organ should bo overcharged with blood. 380. Portal System — Use of tlie Portal System. — An- other apparent exception to the ordinary system of veins is seen in what is called the Portal System. This comprises those vessels which receive their blood from the intestinal canal, the stomach, and the spleen. As these small vessels unite into a larger trunk, instead of passing directly to the heart, they form what is called the Portal Vein, which emp- ties itself into the liver. This vein ramifies into every part of the liver, where the blood is again collected by a series of vessels which unite into several trunks, called the Hepatic Veins, and which convey the blood to the heart. The design of this arrangement is not certainly known as yet, although it is probable that the blood which returns from the alimentary canal is not fitted to enter the general circulation until it has gone through some change in the liver. 381. Origin of llie Vrins — Valves — Their Discoverer. — The Veins all take their ori- gin in the capillary vessels in every part of the body except those of the stomach, and in number and length of tube greatly exceed the vessels of the arterial system. In the lining membrane of the veins, also, w^e find a peculiarity not presented in the arteries. This is the presence of folds, so that pouches or bags are formed, which readily suffer the flow of blood tow^ards the Of whul especial stirvic(5 are they? 880, Describe tlie Portal System. What is the l)robablc use of so marked an exce{)tlon to the c^eneral circulating System? 381. W^here do the Veins take their origin ? What is said of the Valves of the Veins? Tig. 221, h - Vein laid open to show the Valves. Vein, b, Valves. AND PHYSIOLOGY. 219 heart, but almost entirely pre- vent its passage in an oppo- site direction. They act in the same manner as valves in machinery, although with no loss from friction, and conse- quently no necessity of a lu- bricating fluid. It was the discovery of these valves in the veins which led Harvey, an English physician, to the greater discovery of the cir- culation of the blood. He in- ferred that the blood could pass in but one direction through the veins, and conse- quently in the opposite direc- tion through the arteries. 382. Inosculation — Use of Anastomosis. — The arter- ies and veins open into each other (i. e., their own vessels) very frequently, allowing a ready flow of blood from one vessel to the other, even if the flow does not happen to be in the most favorable direction from the center of circulation to the The Superficial Veins on the Front of the Upper Extremity. 1, Axillary Artery. 2, Axillary Vein. 8, Basilic Vein whore it enters the Axillary. 4, 4, Portion of the Basilic Vein which passes under the Brachial Fascia — a portion of the Vein is freed from the Fascia. 5, Point whe.e the Median Ba- silic joins the Basilic Vein. 6, Points to the Posterior Basilic Vein. 8, Anterior Basilio Vein. 9, Point where the Cephalic enters the Axillary Vein. 10, A portion of the same Vein as seen under the Fascia ; the rest is freed from it. 11, Point Avhere the Median Cephalic enters the Cephalic Vein. 12, Lower portion of the Cephalic Vein. 13, Median Cephalic Vein. 14, Median Vein. 15, Anastomosing Branch of the Deep and Superficial Veins of the Arm. 16, Cephalica-Pollicis Vein. 17, Sub-Cutaneous Veins of the Fin- gers. 18, Sub-Cutaneous Palmar Veins. Who discovered the circulation of the blood? 220 HITCHCOCK’S ANATOMY FiOr, 223 . The Arteries and Deep-seated Veins on the Back of the Leg. 1, Popliteal Vein. 2, Popliteal Artery. 3, 4, Vein and Artery in their relative Position on the Back of tlie Knee-Joint. 5, Popliteal Vein on the inner Side of the Joint. 6, Popliteal Ar- tery without and beneath it. 7, Extremity ofSai)hena Minor Vein. 8, 9, Internal Ar- ticular Vessels, both Arteries and Veins, teries and V’'eins. 12, Junction of the Pero ous Branch from the Anterior Tibial Vein. extremities. This relation of parts is called Inosculation or Anastomosis. This arrange- ment gives a plentiful supply of blood to every part of the body, if, by wound or pressure, the ordinary channel of blood to any part should be ob- structed or completely closed up. Inosculation is most abundant in the veins and su- perficial arteries, since these are most liable to be thus im- peded. 383. The Blood — Micro- scopic Structure — Plasma or Serum — Re d Corpuscles — White Corpuscles — Propor- tion of one to the other. — The blood of the human sys- tem amounts to about eighteen pounds, or nearly ten quarts. Is has a specific gravity a lit- tle greater than that of water, is of a bright scarlet color if drawn from an artery, or dark purple if taken from a vein, with a taste slightly alkaline, and an odor resembling that 3, 11, External Articular Vessels, both Ar- eal and Posterior Tibial Veins. 13, A Ven- 14, A Vein from the Gastrocnemius. 15, Anterior Tibial Artery coming through the Interosseous Ligament. 1C, Posterior Tibial Artery. 17, Its two Vena) Coinites. J8, Peroneal Artery. 19, Its two Venae Comites. 20, Vessels on the Heel. 3S2. What is meant by Inosculation or Anastotnosis ? What is the service of anasto- mosis? In what vessels is it luost abundant ? 883. How much blood is there in a hu- jnaA adult? State its color ami odor. AND PIIYSIOLOGA". 221 of the breath of the ani- mal from which it is taken. It penetrates every solid tissue of tie system, as may be known by puncturing any part of the body with even a pin, when blood is sure to follow. If it be ex- amined with a micro- scope when freshly drawn, it appears to be made up of a transparent liquid called the Serum or Plasma, and a num- ber of minute circular bodies, mostly of a red color, called corpuscles, or minute bodies. This fluid is found, on analy- sis, to be made up of water, albumen, fibrin, and several salts, some of which are found in crystals, as is seen in the cut. After it has been drawn from the body a considerable time, it separates into a thickened mass called Coagulum, made up of fibrin and the corpuscles, while the serum with the albumen still remains as a transparent liquid. The Red Corpuscles prove to be flattened discs with both surfaces slightly concave, and measuring about ^^Volh of an inch in diameter, and are in reality nothing but a cell, that is a bag or sac containing a fluid composed of the two proximate principles globuline and hematine. Besides the red corpuscles, there exists another kind in the blood known as the White or Colorless Corpus- cles. They are by no means so abundant, when the body is What is its appearance under the microscoi)e ? ITow does it conduct itself after stand- ing a while in an open vessel ? Describe the Ee4 Corpuscles. Describe the White Cor* puscles. Fig. 225. 0 ® lied Corpuscles of Human Blood. Seen on the Surface, c, Seen in Profile, Seen in a Koll Magnified 400 Diameters. Fig. 224. Crystals from Human Blood. 222 HITCHCOCK’S ANATO^NIY in health, as the red corpuscles. But in certain diseases, and especially if there ho a 'wound in any part of the l)ody to be healed, the 'white corpuscles arc developed at a great rate, although their abundance ceases when the system is restored to a sound state again. Their average diameter is nearly 3 oVoth of an inch, and they appear to be nucleated cells. The proportion of the 'white to the red corpuscles in health is nearly as 1 to 346. The whole amount of blood corpuscles has been estimated as high as 65,570,000,000,000. 884. Effect of an Alternate Exposure to Oxygen and Carbonic Acid . — If the red corpuscles are alternately exposed to oxygen and carbonic acid they lose their circular form, and become corrugated or star-shaped, and finally arc destroyed ; and it is calculated that millions of these corpuscles are de- stroyed at each pulsation of the heart. FUNCTIONS OF THE CIPvCULATORY SYSTEM. 385. The Main Use of the Blood-Vessels — The large Angle made by the Arterial Branches near the Heart. — The first and most obvious use of the blood-vessels is to allow a free and rapid passage of this fluid to every part of the body. This is evident from the smooth lining of all the ar- teries and veins, and from the fact that, with the exception of the large arteries near the heart, the vessels branch off at a small angle from each other, which arrangement offers the least possible obstruction to the passage of the blood. In the organs near the heart, as the head and lungs, the blood would readily pass by smaller vessels and by less force of the heart in sufficient quantity. But in that case the parts of the body quite distant from the center of circulation of the blood would When arc tlio wliito ones the most abundant? State the approximate number of blooc\ cor[)U}»cle8 in one individual. SS4. What elFeet lias an alternate exposure of oxygen and carbonic acid upon these? How many are possibly destroyed at each pulsation of tho heart ? 0S5. Give tho use of tho arteries and veins. AND PHYSIOLOGY. 223 be imperfectly supplied. And apoplexies and congestions would be much more frequent than they now are in the vital organs, if the arteries did not branch off at nearly a right angle. 886. Wliy a large Amount of Arteries and Veins. — The necessity for such a large amount of arteries and veins, and lh3:r numerous connections with each other, is evident from the great variety and extent of the tissues, and also from the great liability to obstruction from inflammations, ac- cidents, or even the ordinary compression of clothing. But arranged as these vessels are in the body, it is a very difficult thing by any mechanical means entirely to check the flow of blood to any part. But were it not for this system of ample inosculation the amputation of a portion of the body would generally produce fatal results. 387. Comparative Capacity of tlic Arteries and Veins. — If all the arteries in the body were to be made into a single vessel, the capacity of it would be much less than that of a similar vessel made by the union of all the veins. This dif- ference in capacity Avill in part result from the feebler char- acter of the forces which propel the blood through the veins than through the arteries, and consequently venous obstruc- tion could not be so easily overcome as if it were in the ar- teries ; and in order to compensate for deficiency in power, an increased amount of tubing is provided. 888. Forces of the Arterial Circulation. — Theinquiry naturally arises. What are the forces that send the blood through the circulatory channels ? 389. Contraction of the Heart— Elasticit y of the Mid- dle Coat. — In the first place the contraction of the heart is the most essential force in driving the blood outwards. This force has been estimated at thirteen pounds, though the re- Why do the arteries near the heart branch off at a large angle? 8S6. Why is there so large an amount of arteries and veins ? 387. What is the comparative capacity of tha veins and the arteries ? 358. What are the forces of the circulation ? 889. What is said of the contraction of the heart ? What is the estimate of the force that it exerts 2 10 * 224 HITCHCOCK’S ANATOMY suit can not be relied on for perfect accuracy; and that this is no inconsiderable force may be inferred from the great amount of resistance that is offered to this current from the ramifica- tions of the smaller arteries, whereby the velocity is increased as well as the surface of resistance. It may also be seen by wounding an artery of medium size, when the blood is sent out in jets, and sometimes to the distance of several feet. This, however, is not the whole amount of the propulsive force in the arterial system, for the middle or elastic coat as- sists by a secondary action. When the ventricle contracts, or the heart beats, the blood is driven into the aorta and its larger branches with so much force, that the middle coat yields considerably, and the artery is distended beyond its ordinary size. As soon as the contraction of the ventricle ceases, of course the blood is forced back towards the heart by the elas- ticity of the artery. But as soon as it commences to flow to- wards the heart the semi-lunar valves close at once, prevent- ing the flow in that direction, so that the whole force of the artery is expended in driving the blood towards the extremities. 390. Pressure of the Muscles. — Another power which aids in the propulsion of the arterial blood is the pressure of the muscles upon the arteries. This is eflected by the en- largement which always takes place in the belly of the mus- cle whenever it is used. This is not a constant power, acting only during exercise of the muscles. 391. Forces of the Venous Circulation. — The agencies by which the blood is returned to the heart are not so well known as those just considered. The valves in the lining membrane of the veins seem to be a contrivance to supply the deficiency of power to drive the blood back. 392. Pressure of the Muscles. — The jDressure of the muscles, without doubt, is another important impulse in When can tlio forces of tlio circulation in arteries be well seen? ITow does the mid- dle coat as.sist in this work? Of what use are the semi-lunar valves? 890. How docs tlio i)resfeure of the muscles aid in the circulation? 891. How do the valves aid in the vefious circulation ? 892. Does muscular iiressurc aid in this? AND PHYSIOLOG’S. 225 aiding the return of blood towards the heart. For, as in the aorta, its elasticity forces the blood, first against the semi- lunar valves and then onwards through the arteries, so the muscles, pressing upon the veins, urge the blood into the pouches or valves on their inner coat, which, preventing re- gurgitation, assist in returning it towards the heart. 393. Respiration. — Respiration is another cause that greatly aids in emptying the veins. In some persons a dis- tinct fullness or pulsation of one of the veins of the neck is noticed during each inspiration. This is produced by the partial vacuum made by the act of inhaling air ; that is, as a pressure is produced on all parts of the body by the atmos- phere, not only a rush of air is made into the mouth, but the blood is forced into the heart by the same cause. And could we examine all the large veins of the body during inspiration, without doubt we should see the blood returning rapidly in them at each inhalation of air. 394. Affinity of Venous Blood for Oxygen.— The afiSnity or desire of venous blood for the oxygen, and the arterial for the tissues, are important causes in the circulation, and es- pecially in the capillaries. It is a principle well known in physics, that if two fluids of diSerent degrees of affinity for a third fluid meet each other in a capillary tube, the fluid hav- ing the strongest aflBnity for the third substance will either partially or wholly force out the other fluid. This takes place equally well through porous substances, membranes, or capil- lary tubes. 395. So that when pure air is present upon one side of the membrane of the lungs and venous blood on the other, the latter urges itself onward to meet the oxygen, and thus forces that which is already purifled into the pulmonary vessels, and thence into the heart. 396. The same thing is seen in the capillaries of the ex- 393 . How does the respiratory act aid the circulation of the blood? 394. How does chemical affinity aid in the circulation ? 226 HITCHCOCK’S ANATOMY trcmities, where the arterial blood, l)y its affinity for the healthy tissues, forces along that Mhich is already surcharged Avith carbonic acid into the systemic veins. 397. Forces of the wliole Circiilntioii. — The forces, then, which propel the blood through the whole system maybe thus briefly summed up : 1. Contraction of the heart. 2. Elasticity of the arteries. 3. Capillary force. 4. Muscular pressure. 5. Act of inspiration. 6. Arterialization of the blood. 398. Course of the lllood lliroiigh the Body. — As al- ready mentioned, the ventricles are the propelling and the auricles the receiving cavities. Hence, in tracing the course of the blood through the body, beginning Avith the left ven- tricle, Ave find the current passing through the aorta and ar- teries to all parts of the body except the lungs. As soon as it has gone through the capillaries it returns to the right au- ricle by the diflerent veins, from which cavity it passes to the right ventricle, and thence to the lungs. After it has received its due supply of oxygen, it is received by the left auricle, from which it passes again to the Avhole system. The parts of this circle and their order are as follows : left ventricle, ar- teries, capillaries, veins, right auricle, right ventricle, lungs, and left auricle. Thus we see that the whole circulation in man and all mammalia follows through the body a course represented by the figure 8. 399. Relative Time Occupied by Contraction of Au- ricles and Ventricles . — The diastole or dilatation of auricles and ventricles occupies a longer period of time than the cor- responding systole, or contraction. If we divide the whole 897. Givo a synopsis of tho circulatory forces. 89S. Give the course taken by the blood as it circulates through tlie body. By what figure may it be represented? 899. What is tho systole and diastole of the heart ? AND PHYSIOLOGY. 227 / 2 Fig. 226. S ^ d G 7 O portion of time occupied by one pulsation into eight intervals, ■vve shall find that the auricles employ only one of these in- tervals in contraction, and the remaining seven by dilatation ; while the time occupied by the contration of the ventricles is the same as their dilatation, as may be seen in the diagram. 400. The Sounds of the Heart — Cause of the First and Second Sound —If the ear be applied over the heart of a healthy person, two sounds will be heard, one of which corresponds in time with the pulsation noticed . Diagram showing the relative Time occu- at the wrist, or any other pied by the Contraction of the Auricles and large artery of the body. Ventncles, the converging imes from ^ o •' ^ right indicating the contraction, and the di- These sounds do not corre- verging ones the dilatation. Auricles. Yentricles. spond to each other in intensity or duration, but are some- what indefinitely represented by the sounds given to the mono- syllables ^Mub’’ and '^dup;’’ the first a long and heavy sound, and the second a short and light one. The first sound is undoubtedly caused by the contraction of the heart, the rush of blood, and the impulse of the organ against the side of the chest ; while the second is the clicking of the semi- lunar valves as they close at the commencement of the aorta after the ventricular contraction. That the last sound is due to this cause is proved by an experiment performed on a dog, of introducing a hook through the aorta, and holding back one of these valves, when the second sound entirely failed. 401. Number of Pulsations per Minute. — The number of pulsations of the heart varies considerably at different pe- riods of life. Thus the following table shows the average number of pulsations each minute at different ages : Give the relative time occupied by the contraction and dilatation of the auricles and ventricles. 400. What two sounds are made at each complete pulsation of the heart? Give the causes of the first sound. What is the last sound owing to ? What proof of it? 228 11 ITCH COCK’S ANATOMY New-born infiint. 130 to 140 During the 1st year 115 “ 130 “ “ 2d “ 100 “ 115 From the 7th to the 14th year 80 “ 90 “ 14th “ 21st “ 75 “ 85 “ 21st “ GOth 70 “ 75 Old ago 75 “ 80 402. Causes affecting the Pulsations. — Muscular exer- tion lias a considerable influence upon the rapidity of the con- traction of the heart. So also has the position of the body, whether sitting, lying, or standing. The time of day or night likewise has an important influence, the highest number of pulsations being found at noon, and the fewest at mid- night. 403. Use of the Corpuscles. — The function of the Red Corpuscles seems to be to convey oxygen to the tissues, and as this is the agent which is continually promoting the change or waste of the system, these corpuscles seem to be the great agents for disassimilating the tissues and the blood itself. The colorless or white corpuscles seem to be the agents by which the repair of the body is effected, since they are greatly aug- mented in number when there is a large wound to be healed, or when there is a great amount of internal or external in- flammation. 403a. Statistics. — In an ordinary life of a man the heart beats at least 3, 000,001), 000 times, and propels through the aorta one half a million tons of blood. HYGIENIC INFERENCES. 404. hut few Diseases of the Circulatory Organs. — 1. Though the blood-vessels are so constantly in use, and so easily excited by every muscular movement and mental emo- tion, yet they are affected by only a few diseases, and many 401. State the miinher of pulsations of the heart at different periods of life. 402. What causes modify the number of the pulsations? 403. What is the probable business of the lie(l Corpubclcb? What of the White? 404. Arc there many diseases of the Circulatory organs ? AND PHYSIOLOGY. 229 of these aifectionSj which seem to be diseases of the heart, are merely sympathetic, and the difficulty lies in other organs. 405. Avoidance of sudden Efforts. — 2. But those per- sons who have a tendency to diseases of the heart, sympa- thetic or organic, should be on their guard against sudden exertions, and, to as great an extent as possible, avoid mental anxiety and alarms. Heart diseases are most common late in life, at or about sixty years of age. 406. Principal Danger from Wounds.— Treatment of IVounds of Arteries. — 3. The principal danger to be feared from these organs results from wounds. If these are in the arteries, they require prompt attention, but if in the veins, they need scarcely ever excite fear. If an artery be wounded — which can always be known by the escape of blood in jets, and not a steady stream — the wound should be either closed, or the artery pressed upon between the wound and the heart with so much force as to stop the flow of blood through it. In case of any such arterial wound it will always be well to tie a bandage as tight as possible immediately over the wound, and then compress the artery as already mentioned. If the wound be on the hand or forearm, the brachial artery may be found and compressed just above the inner angle of the elbow. Or if it is desirable to compress the artery still higher up, the axillary artery may be found in the armpit, where by pressing outwards, nearly all the blood flowing to the arm may be checked. 407. Method of Checking the Blood to the lower Ex- tremities .—4. If it is desired to check the flow of blood to the lower extremity, the popliteal artery lies directly against the femur upon the backside of the knee-joint, where a compres- sion of it may be effected with great advantage. Nearer the heart (in the groin) the femoral artery is found, where it 405. What should those persons j)re{Iisposed to these diseases especially be on their guard against? At what time of life are Heart diseases the most frequent? 408. How can we distinguish between the wound of a vein and that of an artery ? How may ar- terial hemorrhage be most readily checked in the upper extremities ? 407. How may it be checked in the lower extremities ? 230 niTC II cock’s anatomy crosses the os innominatum lying just beneath the skin. Hero an eflScient compression may be made, since all the anterior part of the thigh and the whole of the leg proper, is supplied with blood from this artery. 408. 5. Except bad wounds, however, a tightly drawn band- age, directly over the wound, thoroughly wet with cold water, will check hemorrhage suflSciently, until a surgeon can be called. COMPARATIVE ANGIOLOGY. 409. Heart of Manimals.- Fig. 22Y. Circulation in Man. a. Eight Auricle. h. liiglit Ventricle, e. Left Auricle, d. J.eft Ventricle, e. Aorta, f. Vena Cava. (j. Pulmonary Artery. h. Pulmonary Veins. In all mammals the heart is divided into four cavities, as in man. Its form, however, is more rounded and less elon- gated. In one species of the whale this organ is cleft in a peculiar manner, the division between the two ventricles being indicated externally by a deep fissure in its apex. In the Ox, Hog, Sheep, and Goat there are always found one or two bones in the di- visions between the ventri- cles. In most mammals it is placed more in a right line with the middle of the body, and not so obliquely as iu man. 403. What treatment will chock all ordinary hemorrhages? 409. What is peculiar m the heart of the Whale, the O.v, the Sheep, and Goat? Where is the heart located ic quadrupeds ? AND PHYSIOLOGY. 231 410. Aorta and Pulmonary Veins.— The manner in which the Aorta and its branches are given off varies greatly in these animals, as may be seen by the cut. The number of Pulmo- Fig. 228 . A BODE FGH a ha ha h a h a ha hah a Diagram of the Principal Varieties of the Aorta in its Principal Branches in a, Man ; B, Elephant c, Cetacea; d, Bat; e, Carnivora; r. Seal; G» Euminants ; n, Reptiles. 1, Eight Subclavian. 2, Eight Carotid. 3, Left Carotid. 4, Left Subclavian. 5, Verte- bral. a, Ascending and b Descending Aorta. nary Veins varies upon the different sides of the body, and is generally according to the number of lobes in the lungs, the relations of the sides being represented by the formula 3f2. 411. Economy of Diving Animals. — In diving animals the vena cava is capable of great dilatation, in order to contain an unusual quantity of blood which accumulates there when the animal suspends respiration under water, since it can not be purified except in the lungs. Still further protection to the heart in diving animals is seen in the vena cava ascendens, where a circular muscle, by its contraction, can completely cut off the flow of blood to the heart Fig. 229 . from the lower extremities. 412. Blood Corpuscles of Mammals — Wonder Nets. — The blood of mammals, for the most part, presents small round, disc-shaped corpuscles, similar to, but smaller than those in man. This is especially B A Eed Corpuscles of the Ox. A, In their Natural State, a, Seen in Profile. Seen on the Surface. B, Altered Corpuscles. 410. What is peculiar about the aorta and pulmonary veins in many mammals? 411, What is the arrangement of the vena in diving animals ? 232 n ITCH cock’s anatomy -r^K - •; true of ruminants. The largest animals, such as the elephant, have very small corpuscles. In some of the camels and llamas the corpuscles are large and somewhat elongated. The same Fig. 230. is true of the dromedary. Crystalline substances are found in the blood of other mammals as well as man. The an- nexed cut shows crystals from the blood of the Guinea pig. The distribution ot the arteries of quadru- peds is a subject of con- siderable interest. In grazing animals, which Blood Crystals of the Guinea Pig. hold their heads low, in addition to large arterial trunks, we find a great number of very small ones, which are exceedingly tortuous in their course, called Wonder Nets.” This arrangement is to prevent a too rapid flow of blood to the head by the force of gravity, which ■would of necessity take place when the head is so constantly in a dependent position. A similar disposition is seen in the limbs of the sloth and other animals which are like them in tardiness of movement. In the fore-leg of the lion, where great muscular force is exerted, the main artery passes through a perforation in the bone, so as to secure it from obstruction to the flow of blood by pressure of the rigid muscles. 413. Heart of Birds. — The heart of birds is highly mus- cular and of very large size in proportion to the bulk of the body, and in general structure resembles the same organ in mammals. The valves of the right ventricles, how^ever, are supplied with a strong band of muscular fibers, which gives -112. Whiit is i>eculiar about tlio blooil discs or cori»nscle.s of the larger animals? What is the form of nearly all of them? In Avluit animals ar c they oval ? What are Winder Nets, and why arc they introduced? 413. What is worthy of note with refer- ence to the heart of birds ? AND PHYSIOLOGY 233 Why ao the valves have au especial muscle? additional impulse to the blood as it is forced into the pulmo- nary arteries The need of this arrangement is to give a full supply of blood to the lungs, which the ordinary powers of the heart could not effect. Fia. 231. Arterial System of a Bird. Arteries of the Grebe, a, Aorta, aw, One of its large Branches. It gives off the Carotid (ac) and Subclavian, is ultimately distributed to the muscles of the chest, and corresponds to the mammary arteries of mammals, a-y, One of the Branches of the Vertebral Artery supplying the Muscles of the Shoulder, ce. Arterial Loops formed by the Branches of the External Carotid, al. Lingual Artery, t, Trachea, or wind-pipe, ar. Renal Arterie.s. at, Ischiatic Artery proceeding to the lower extremities, as. Sac- ral Artery, forming a continuation of the Aorta, and giving origin to the Inferior Mesen- teric Artery, etc. cl, The Cloaca. 234 HITCHCOCK’S ANATO]SIY 414. Arteries — Wonder Jlets. — The trunk of tlic aorta is very short, and after giving arteries to supply the heart it di- vides at once into two large branches, quite unlike the con- formation in mammalia. Wonder nets, too, are often found in birds, and especially in those arteries supplying the brain, eyes and legs. 415. Blood. — The blood of Fig. 232. birds has the highest tem- 0 perature of the vertebrate animals — 110° F. The blood cells, or corpuscles, are al- ways of an elliptical form and of a very uniform diameter. A Pigeon’s Blood (red) Corpuscles Magni- fied 4U0 Diameters. A, In Natural State. B, Altered by Acetic Acid. 416. Heart of Reptiles. — The heart of reptiles ordinarily consists of a single ventricle, Fig. 233. Fig. 234. or propelling cavity, and two auri- cles, or receiving cavities, so that the pure blood is mixed with the impure (or a portion of it) as it Circulation In Reptiles, a, Heart, b. Ventricle, c, c, Auricles. comes from the lungs, which accounts in part for the general sluggishness of these animals. The blood corpuscles of rep- tiles are large and oval, as may be seen in Fig. 234. 'll 4. Into how many branches does the aorta at once divide ? Where are wonder nets found in binls? 415. Wliat is said of the temperature of birds ? What of blood-cells ? 416. Describe the heart of reptiles. What is the elfoct upon the blood? What is the size of their blood-vessels? AND PHYSIOLO GY. 235 417. Blood-Vessels. — The arrangement of Blood-Vessels is very diverse, since one portion of them breathe by gills and another by lungs, while frogs in their early condition are fur- Fia. 235. Carotid /Artery. Arches of ^ the Aorta. N Right Auricle. Intestines. Circulatory Apparatus in the Lizard. 417. Why are blood-vessels arranged differently in many of the reptiles ? 236 HITCHCOCK’S anatomy nislied Avitli the former, but in adult age, after passing tlirougli a metamorphosis, have the latter system of respiratory vessels. 418. Heart of Crocodile. — Crocodiles and turtles ex- hibit the most perfect form of heart, for it agrees essentially with that of mammals, as may be seen in Figs 236 and 237. But there is a small opening just at the outlet of the two ventricles, so that the pure and impure blood is mixed. 419. Portal System.— Reptiles have a double Portal System, one set of vessels supplying the kidneys and another the liver. 420. Lymphatic Hearts. — Many reptiles have small sac- like organs lying just beneath the skin in certain portions of the body, wdiich, from their containing lymph and showing Fig. 231 . pulsations, are called Lymphatic Hearts. In the Frog, two such hearts are situated on the back of the animal, between the joints of the thigh bones. Fig. 236. ao c c a Heart of Crocodile. Veins, rto, Uijjht Auricle, 'vt. Ventricles, ap, Pulmonary Arteries, or, A Vessel proceeding from the Ventricle to the Aorta, og, Left Auricle. 4 IS. What animals of this class have the most pc'rfcct form of a heart? 419. What kind of a iK)rtttl system do wo liiul among reptiles? 420. Describe lymphatic hearts. AND PHYSIOLOGY. 237 421. Heart of Fishes. — The heart consists of one auricle and one ventricle, which are covered bj a pericardium, and the whole organ is very small in proportion to the size of the whole body, being from 4 ^ to T oV weight. In the osseous fishes the heart is elongated and conical, while in the Sharks and Rays it is broader. The ventricle dis- charges its blood through the aortic trunk upon the gills. This trunk divides up into a large number of minute branches w^hich ramify upon the gills, and after the blood has received its oxygen from the water, it is collected by a corresponding set of ves- sels, and emptied into another trunk which supplies all the rest of the body — which trunk corresponds to the aorta — though it has no muscular Fig. 238. dj Circulation in Fishes. «, Heart, Auricle, c, Ventricle. Circulation through the Gills, or Lesser Circulation. (7, Circulaticn through the Body, or Greater Circulation, e, Arteries. ^ Veins. power to propel the blood along. After it has performed its office it is collected by a system of vessels similar to veins, and returned to the auricle. 422. Pulsations in a Minute. — Commonly not more than twenty or thirty beats in a minute may be counted in fishes, while in birds one hundred may be counted in the same time. 423. Portal Circulation. — In fishes, as in reptiles, there seems to be a double portal circulation. 421. Why is the heart of the osseous fishes called abranchial heart? What proportion of the body docs it constitute ? Give tlie course of circulation. 422. What number of pulsations can bo counted in the heart of fishes, and what number in birds ? 238 HITCHCOCK’S ANATOMY FlO. 239. 424. Accessory Hearts-— Caudal Heart. — Among many fishes are found what are termed Accessory Hearts, or small muscular organs which seem to aid in the propulsion of blood through the difierent parts of the body. Thus, in the myxine, the portal vein is distended into a large sac, which expands and contracts alternately; and in eels there is found upon 424. Wbat are the accessory hearts of fishes 7 AND PHYSIOLOGY. 239 both sides of the last caudal vertebra a pulsating organ which receives the blood from the delicate veins of the caudal fin, and propels it into the caudal vein, this constituting a true caudal heart. 425. Fishes’ Blood. — The blood of fishes, almost without exception, is of a red color, and contains oval and slightly bi-convex corpuscles. In one family they are distinguished by their great size, and thus resemble those of frogs ; but other families have smaller ones. Fig. 241. Smaller Circulation. Branchio-Cardia« Canals. Heart. Arteries. Greater Circulation. Diagram of the Circulation in Fishes. 426. Dorsal Vessel, or Heart of Articulates. — In ar- ticulata, a vessel or tube passes along the back of the body — behind the intestines and in front of the chain of ganglia — called the Dorsal Vessel, which is divided into as many por- tions as there are segments of the body. This is really tha Fig. 240. Blood Corpuscles of a, Lamprey Eel ; Skate. What peculiarity in the tail of the eel ? 4-5. What is the color of fishes’ blood, and what are its corpsucles ? 426. WTiat is the Dorsal Vessel of articulates ? 11 240 HITCHCOCK’S ANATOMY Fia. 242. e fia d J) a Circulatory Apparatus in the Lobster. 27. Wluit i.s the amount of walcry Ihiid discharged from the body? 528. What is said of the distrihution of the hair? JIow long has tlie liuir ])ci‘n known to grow? 529. What is the diameter of tlie hair? What is the ehaj^e of it? What glands empty their contents upon the base of each hair? AND PHYSIOLOGY. 303 contents into the same pore in ■which the hair itself is lo- cated. This secretion is an oil which keeps the hair in a smooth and moist state. 530. Tlicir Number. — The number of the hairs varies with the color and portion of the body. In one case there were found on the same sur- face 147 black hairs, 162 brown, and 182 blonde. On a surface one fourth of an inch square the same author found on the scalp 293 hairs and on the chin 39. Layer from 531. Their Distribution and Direction —They are implanted either singly or in twos or threes, or even four or five together, and their direction is rarely perpendicular to the skin, being, in a natural state, downwards. They may, however, be changed in their direction by persevering efforts, as is sometimes seen by the brushing of the hair away from the forehead. 532. Chemical Composition— Dnrabillty.— They differ from most tissues of the body by containing ten per cent, of sulphur. This, together with the fact that they contain a large per cent, of nitrogen, accounts for the unpleasant odor given off while burning. They resist decomposition better than most of the tissues. Those of Egyptian mummies re- main quite unchanged. And it is owing to their durability that they are used as relics of departed friends. l. 295. ). a, Oil Glands. 530. What is said of the number of hairs on the body? 531. How are they distributed, and what direction do they take ? 532. How do they differ from most other tissues in chemical composition? How durable is hair? 804 HITCH cock’s anatomy 533. Constiliilion. — In constitution the hair con- sists of three distinct por- tions, an epidermis or outer portion, a fibrous, and a med- ullary portion. The epider- mis is arranged in the form of ring-like scales, wliicli overlap each other like the shingles of a house, and is about ioVoth of an inch thick (Fig. 294, rfj. Hence we see the reason why we can brush the hair in only one direction. The fibrous portion makes up the prin- Iliglily Magnified Root of Hair, a. Shaft cipal bulk of the hair, and of Hair, 5, c, Epidermic Sheath of Hair, i r* i • i • i Dermic, or External Sheath of Ilair. e, Epi- IS COmpOSed ot lOUgltudinal dermic Scales. cells, wliicli Contain paint granules and air cavities which give the color to the hair. The medullary portion constitutes the central part of the hair (usually from one third to one fifth its diameter), and is made up of cells varying in diameter from e e o of an inch in diameter. 533 a. Color. — The color of the hair is thought by some to be owing to the iron contained in it, since it is said that there is the most of this metal in the darkest hair. 533 b. Pliysical Properties.' — Hair is so elastic that it will stretch without breaking to nearly one third more than its original length. A single hair of the head will support six ounces without breaking. It readily absorbs moisture, and is dry and brittle or moist and soft, according as the skin or atmosphere is dry or moist. The beard is abundantly Fig. 296. c b a be r.dfl, Wliat tlirec portWms is oac-li lialr coiistiUitod of? Wliat makes the principal jiart \T (Iocs it nfFo(^t tlio skin at the joints? Of what service is it to the eye? Of what to the car ? 510. State tlio relative value of the skin in the animal economy. 541. Why i.s cleanlines.s essential for the health of the skin ? AND PHYSIOLOGY. 309 quently washing the whole surface of the skin, but also the frequent change of the bed-clothes, under-clothes, etc. And it should be a fixed rule with every one to change the linen and under-garments both night and morning ; that is, the under-garment worn during the day should not be worn at night, and the reverse. 542. — 3. Must be Kept at a Uniform Temperature.— We also learn that the skin should be kept at a uniform tem- perature, and up to its normal standard. It therefore needs proper clothing, not so much in the coldest weather — for then our feelings will impel us to do it — ^but at the changes of tem- perature so common and so great in our climate in spring and autumn, for then we are too apt to neglect it because we feel no especial inconvenience, and yet at these times there is more danger of disease from a want of proper clothing than at any other season of the year. We seldom injure ourselves by too much clothing, because we can easily throw of superflu- ous garments, but often do it by too small an amount of pro- tection. An important rule for every one is, when going abroad even a short distance from home, to carry with him an over garment when exposed to evening air. 543. — 4. Must Come in Contact with the Air.— The skin imbibes oxygen from the air, and hence it is important that air be brought in contact with this membrane. The clothing should be worn so loosely that a thin layer of air will be in contact with nearly every part of the skin. 544. — 5. Needs Friction. — Frequent and thorough dry friction applied to every part of the skin greatly promotes the health, not only of this membrane, but of the whole body. So smooth are the clothes we generally wear next the skin, that but little stimulus is received by them, and hence a thorough 542. What is necessary for the temperature of the skin, especially for changes in weather? What is said of an over-coat as a constant traveling companion ? 543. Why should the skin have air in contact with it ? 544. What is the use of friction to th® skin ? 310 HITCHCOCK’S ANATOMY rubbing of the whole body every night and morning will aid greatly in this matter. 545. — 6. Injurious Effects of Moisture upon the Skin. — Moisture if applied to the skin for a considerable length of time interrupts its functions, and accordingly we infer that wet or damp clothing should not be allowed to remain on the body any longer than is absolutely necessary. If, however, dry clothing cannot be procured immediately, the body should be kept in vigorous action of some kind until the clothes can be changed. This inference is of equal application, whether the whole of the body be wet, or only a portion of it, as the feet. 546. — 7. Service of a Daily Cold Water Bath. — We in- fer again that a daily cold water bath is of great service for all students and sedentary persons who are in health. Not only is it desirable on account of cleanliness, but a serviceable shock is thus imparted to the nervous system. It, however, should be taken as speedily as possible, the essential thing desired being, that pure water should be spread over the whole surface of the body, and after it that the skin should be speedily and vigorously wiped dry. The secondary effect, however, the stimulus imparted to the nervous system by the shock, is by no means an unimportant issue to be gained. COMPARATIVE DERMATOLOGY. 547. Covering of Mammals, — The skin of mammals very closely resembles that of man, with the exception of the epi- dermis and its horny appendages, which are usually covered by hair. The fat tissue, too, just beneath the skin, is often develop- ed in a surprising degree, and the corium in many instances is very thick. Some have horny scales, and others long plates. rur>. Wlifit nro the iiijiirioiis ciructs of too much moisture applied to the skin? 546. What Irt said of a daily hat li, and what regulations concerning it? 547. What is said ol the covering of mammals? AND PHYSIOLOGY. Sll 548. Callosities. — In many of the rodent or gnawing ani- mals, the carnivora and camels, the epidermis about the joints becomes very thick, making callosities or pads for the sup- port and protection of the parts exposed. 549. Epidermic Scales. — True Epidermic Scales are found on the tails of many animals, such as the Beaver. 550. Horn of Rhinoceros,— The so-called horn of the Khinoceros is nothing but a thickening of the epidermis until is assumes the form of a hollow cone. 551. Varieties of Hair.^The hairs upon the external surface of mammals either present no greater irregularities Pig. 298. Fig. 299. Hair of Sable. Hair of Musk Deer. than do those of man, or they are slightly rough, like those of the Squirrel, or knotty, as in the Bear, or furnished with pointed processes, like the teeth of a saw, in other animals. Some of these peculiarities are exhibited in the adjoining cuts. The spines of the Porcupine and Hedgehog differ from hairs only that they contain the same materials in a more con- densed form. 552. Glands of the Skin. — Cutaneous and sebaceous glands are present in most mammals very abundantly. The 548. To which membrane of the skin do the callosities of camels, etc., belong? 519. Where are epidermic scales found? 650. What is the horn of the rhinoceros? 551. What are the varieties of hair in different animals? 652. What is said of glands of the skin 312 HITCHCOCK’S ANATOMY Fig. 300. Fio. 301. Transverse Section of Hair of Pccftrl, A. B, Hairs of Squirrel. C. Hair of Indian Bat. latter secrete an unctions fluid, which is usually of a strong smell. 553. Skin of Birds. — The Skin of Birds is thin and desti- tute of cutaneous glands, except one at the tail, which is gen- erally present. The whole body is covered by feathers, except certain parts of the head, legs, and feet. There it becomes very much thickened, forming callosities, wattles and combs, in which, beside the cellular tissue, are found the elastic and erec- tile tissues, as well as red and blue cells of coloring matter. Upon the toes and feet are found plates and scales of horny tissue. 554. Feathers of Birds. — The Feathers of Birds are made up of the Quill and Vane: the former giving it attach- ment to the body, and the latter forming its expanded surface. The Vane is made up of a small number of laminae or plates, which both form a light and firmly resisting medium to the air, and serve to retain the heat within the body. When per- fectly formed the laminae are furnished with a booklet at their free extremities, by which they are attached to each other, r>r)3. What is tlio tliickness of the skin of birds compared with that of mammals? What are the wattles and combs? 5.51. What two ]>arts are feathers made up of? Why are the lamina*, furnished with a barb at each extremity ? What is the design of their overlapping each other ? AND PHYSIOLOGY. 313 thus making each feather an impenetrable plane surface. The feathers also overlap one another to a considerable de- gree, and as they thus contain air, and are themselves non- conductors, they afford the most perfect protection to the body against the cold. 555. Skin of Amphibia. — The naked Amphibia, such as the Frogs, have a smooth slippery skin, which is continually being cast off in patches or shreds. This skin surrounds the solid parts of the body very loosely, and spaces for lymphatic vessels are found beneath. It is always composed of several layers of fibres which lie at right angles with each other. 556. Scales of Serpents. — Upon some serpents, scales are found which overlap one another, like the shingles of a house, as is also the case with fishes. Scales with tubercular spines are met with on some reptiles, and in some instances, as those of Crocodiles and Tortoises, they contain bony matter, and coalesce with the bones of the skeleton. 557. Exnviation of Serpents. — Many Serpents cast their skin several times during the year, either by piecemeal, or by drawing off the whole at once. One species of Tortoise does the same thing, as well as several Lizards. This is an anal- ogous function to the moulting of birds, and shedding of the coat in mammals. This generally takes place in Spring, but frequently upon a change of weather several times in the year. At each period, when this is effected by the Rattle- Snake, a new segment is said to be added to the tail, which seems quite probable, since the rattle is merely a condensed portion of the epidermis. 558. Scales of Fishes. — Classification of Fishes hy their Scales. — Fishes have an Epidermis which is sometimes covered with scales, and sometimes not, though always lubri- cated most thoroughly by a copious mucous secretion. The 555, What is said of the skin of frogs ? 556. Do serpents ever have scales ? 557. What is tlic exuviation of serpents? When does this take place? What peculiarity in tho rattle-snake? 558. How are tho scales of fishes arranged? 314 II ITCH cock’s anatomy scales are sometimes disposed in an imbricated manner upon the body, and are not situated in the epidermis, ‘‘but really in the skin, and included by it.’’ The scales contain both phosphate and carbonate of lime as a rule. Their shapes arc various, though Professor Agassiz, the best living authority on fishes, has grouped all bony fishes under four orders, de- pendent mainly upon the form of the scale. First, the Pla- coidians, including such fishes as the Sharks and Rays, where the scales are cither large and covered with bony tubercles, or simply with small enameled scales. Second, the Ganoi- dians, including the Sturgeon and bony Pike, which have angular bony plates coated with a thick layer of enamel. Third, the Otenoidians, such as the Perch, which have hard scales jagged on the outer edges, like the teeth of a comb. Fourth, Cycloidians. These have soft and circular scales with simple margins. In this order are found the Herring and Sal- mon. Sometimes the scales are provided with a hook-like process, which overlaps and fastens itself into a depression in the scale beneath. 559. Tegument of Articulata. — Horny Case of In- sects. — The Tegumentary envelop of the sub-kingdom Arti- culata has already been described under Comparative Oste- ology, since the skin of many of this sub-kingdom, especially the Crustacea and insects, is in reality the only skeleton these animals have. Insects have a covering sometimes leathery and soft, and sometimes horny and solid, which contains a peculiar proximate (chemical) principle known as Chitine. 560. Ill nil tie of Molluscs, — In Molluscous animals, a dermis, which is a muscular skin, envelops all the viscera, and hence is called the cloak or mantle, which secretes tho hard calcareous covering knoAvn as the shell. Generally the shell is external to the mantle, as in the Clam and Oyster, Wlifit arc 1 ho four orders (lopondont upon tlio form of the scale? Who is the author (.f this arrauj'cmcnt ? (Jive cxami)los of each. 559. What is the covering of the articu- hii.a? What is peculiar about its chemical composition? 560. Describe the outside cov- ering of molluscs. AND PHYSIOLOGY. 315 but often, as in the Cypraea or Cowry, the mantle extends over the shell. 661. Radiates. — With the exception of the hard external skeleton of these animals already described, their proper skin is mostly thin and soft, allowing of great flexibility and some- times of great expansion and contraction. The Protozoa have a very delicate, cutaneous envelope, sometimes smooth and sometimes covered with cilia. Effect of Fright on Hair . — A Sepoy of the Bengal Army, brought as a prisoner for examination before the British officers, was terribly affrighted, trembled like a lea^ and was almost stupified with fear. Such was the shock upon his brain that his hair, from a glossy jet black, became gray within the space of an hour, the subject being only twenty- four years of age. Also a boy, let down from a high cliff on the coast of Scotland to get eggs of sea-birds. He, in defending himself from the birds with the sword, struck the rope by which he was suspended, and cut off every strand but one. When drawn up his hair was white. Maria Antoinette experienced a change in the color of her hair during one night’s excessive fear. CHAPTER SEVENTH. THE INSTRUMENTS OF ANIMATION.— NEUROLOGY, OR THE BRAIN AND NERVES. DEFINITIONS AND DESCRIPTIONS. 562 . Main Features of the Nervous System. — We now come to an organization which is very complicated in structure, some of whose functions are the most obscure of any in the body. It is called the Nervous System : and the different grades in the animal kingdom are established by placing those having the most complicated nervous system highest on the scale. Man having the largest brain in pro- portion to the rest of his body, and possessed of the greatest relative amount of nerves, is therefore placed at the head of the animal kingdom. 563 . Microscopic Structure. — Tubular Portiou.— Diam- eter of the Tubes. — In microscopic structure the nervous tissue presents two essential elements : the fibrous or tubular, which is mainly found in the nerve trunks, and the cellular or vesicular, existing more abundantly in the ganglia or nerve centers. In the former the tubes are the largest in the trunks of the nerves, and gradually diminish as they approach the brain, varying in size from the 2 oVoth- the 2 t ^ 0 oth of an inch, and sometimes existing even as large as the 5^oth of an inch. They are sometimes conical also, measuring at one end from 7 2*0 oth of an inch to 27 io oth : the smallest end being found near the nerve trunks, and are sometimes called coarse 502. Olvo tlio leading features of the nervous system. 6C3. What are tlie two micro- scopic elements of nervous tissue ? Give the size of the tubular portion. AND PHYSIOLOGY. 317 Pia 302. nerve fibers. These fibers have the appearance of a double tube, or a small tube within a larger one, and sometimes exhibit small nucleated cells within the two. 564. A closer examination shows an inner or grayish por- tion which is called the axis cylinder, and a white substance around this called the medullary matter, or substance of Schwan, and outside of the whole a membranous tube. (Fig. 302.) They are often called Fine Nerve Fibers. The sym- pathetic system, on the other hand, seems to be made up of tubes without this double structure, and wdien several of them are joined in a bundle, they present a grayish appear- ance. They are also of a much smaller size, varying mostly from Tilo oth to g Ao^h of an inch. 565. Vesicular Structure. — The vesicular substance is composed of cells or vesicles, wdiich present very curious forms, being somewhat stellate or caudate. The central por- tion is globular, consisting of a nucleated cell, which sends off processes in different directions, as seen in the annexed Figure 803. Their diameter is exceedingly variable, meas- W'hat is the structure of the sympathetic system ? 5G4. What still more minute struc- ture can be detected by the microscope ? 5G5. Describe the vesicular structure. Give the diameter of the cells. 318 HITCHCOCK’S ANATOAtY Fia. 303. Vesicular Nerve Corpuscles, a. Cell Wall. h. Cell Contents, c. Pigment, d. Nu- cleus. e. Prolongation forming Sheath of the fiber. /. Nerve Fiber, magnified 350 diam- eter. uring from 7 J oth to ^oVotli of an inch. These are found in the ganglia and the substance of the brain. 566. Divisions of the Nervous System. — The nervous system consists of a central portion contained within the cav- ity of the skull and the spinal column, and a great number of white threads ramifying through every part of the body. The physical condition upon which the activity of the ner- vous system depends, is the supply of arterial blood. 567. Cerehriim, — If we examine the parts wdthin the skull, (Fig. 304, p. 319,) we shall find the greater mass of it to be of a spheroidal form, divided nearly into two halves by a deep fissure or cleft, and its surface is singularly roughened by elevations and depressions called anfractuosities. 568. This mass is the Cerebrum or Great Brain, and the two divisions are called its hemispheres. (Fig. 307, p. 321.) 569. In man the average weight of the brain is fifty>four ounces, in females forty-five; the maximum being sixty- four, 500. Wliat i)rincipal divisions docs tho nervous system consist of? 507. Describe the cerebrum. 509. W hat is tho average weight of tho braiu? 319 AND PHYSIOLOGY. Fia. 304. a f h c Tertical Section of the Brain, Cerebellum, Pons Yarolii, and Medulla Oblongata, a, Anterior Lobe of the Brain. 5, Middle Lobe, c, Posterior Lobe. Cerebellum, e, Me- dulla Spinalis, f. Section of the Corpus Callosum. The Lateral Ventricles of the Brain are situated on either side of the Corpus Callosum, which assists in forming their Upper 'Wall, gr, Optic Lobes: 1, Olfactory Nerves. 2, The Eyeball, from which may be traced the Optic Nerve as far as the Optic Thalami or Lobes. Close to this is the Nerve of the Third Pair. 4, The Fourth Pair, distributed, like the Third, to the Muscles of tlio Eyes. 5, Superior Maxillary Branch of the Fifth Pair. 5', Ophthalmic Branch of the same Pair of Nerves. 5", Inferior Maxillary Branch of the same Pair of Nerves. 6, Sixth Pair, proceeding to the Abducentes Muscle. 7, Facial Nerve : — under the origin of this nerve may be seen a portion of the Acoustic. 9, Nerve called Glosso-Pharyngeal. 10, Pneumogastric Nerve ; close to it is 12, the Spinal Accessory. These three Nerves, the Glosso-Pharyngeal, Pneumogastric, and Spinal Accessory, are by some reckoned as one pair. 11, The Ninth Pair of some, and the Eleventh of others, called also Hypoglossal. 14 and 15, Cervical Nerves. and the minimum twenty ; the average capacity of the cra- nia of Germans and Anglo-Saxons is ninety cubic inches. Daniel Webster’s cranium contained 122 cubic inches. 570. Cerebellum, — The Cerebrum, by a band of thick fibers, is connected with another body, of a pear shape, at- tached to it by its base, called the Lesser Brain or Cerebel- 1am. (Big. 306, p. 320.) This has about one eighth of the State tlie average capacity of Anglo-Saxon crania, and also that of Daniel Webster. 570. Describe the cerebellum. 14 * 320 TI I T 0 II C O C K ’ S ANATOMY weight of the Cerebrum, and lies directly behind and be- neath it. Fig. 305. The Lateral Tentriclos of the CiTcbruin. 1, 1, The two lloini- ppheres cut down to a level with the Cor[>us Callosum, so as to show the Centrum Ovale Majus. The Surface is studded with the small Puncta Vasculosa. 2, A small portion of the Anterior Ex’ tremity of the Corpus Callosum. 3, Its Posterior Boundary ; the in- termediate portion, forming the Eoof of the Lateral Ventricles, has been removed so as to completely expose these Cavities. 4, A part of the Septum Lucidum, showing a space between its Layers which is the Fifth Ventricle. 5, The An- terior Cornu of one Side. 6, The commencement of the Middle Cornu. 7, The Posterior Cornu. 8, The Corpus Striatum of one Ventricle. 9, The Taenia Striata. 10, A small part of the Thalamus Opticus. 11, The Plexus Cho- roides. 12, The Fornix. 13, The commencement of the Hippocam- pus Major in the Middle Cornu. The Pounded Oblong Body in the Posterior Cornu of the Lateral Ventricle, directly behind the Figure 13, is the Hippocampus Minor. A Bristle is seen in the Foramen of Munro. Fig. 306. » 1 A View of the Interior Surface of the Cerebellum and a Portion of the Medulla Ob- longata. 1, 1, The Circumference of the Cerebellum. 2, 2, The two Hemispheres of the Cerebellum. 3, Lobulus Amygdaloides. 4, The Vermis Inferior. 5, Lobulus Nervi Pneumogastrici. 6, The Calamus Scriptorius. 7, Its Point. 8, Section of the Medulla Oblongata. 9, Points to the Origin of the Pnoumogastric Nerve. AND PHYSIOLOGY 321 571. Cerebral Ganglia. — Also lying directly upon the base of the brain, are found several distinct enlargements or Fig. 307. A View of the Base of the Cerebrum and Cerebellum, together with their Nerves. 1, Anterior Extremity of the Fissure of the Hemispheres of the Brain. 2, Posterior Ex- tremity of the same Fissure. 8, The Anterior Lobes of the Cerebrum. 4, Its Middle Lobe. 5, The Fissure of Sylvius. 6, The Posterior Lobe of the Cerebrum. 7, The Point of the Infundibulum. 8, Its Body. 9, The Corpora Albicantia. 10, Cineritius Matter. 11, The Crura Cerebri. 12, The Pons Varolii. 18, The Top of the Medulla Oblongata. 14, Posterior Prolongation of the Pons Varolii. 15, Middle of the Cerebel- lum. 16, Anterior Part of the Cerebellum. 17, Its Posterior Part and the. Fissure of its Hemispheres. 18, Superior Part of the Medulla Spinalis. 19, Middle Fissure of the Medulla Oblongata. 20, The Corpus Pyramidale. 21, The Corpus Restiforme. 22, Tlia Corpus Olivare. 28, The Olfactory Nerve. 24, Its Bulb. 25, Its External Root. 26, Its Middle Root. 27, Its Internal Root. 28, The Optic Nerve beyond the Chiasm. 29, The Optic Nerve before the Chiasm. 80, The Motor Oculi, or Third Pair of Nerves. 81, The Fourth Pair, or Pathetic Nerves. 82, The Fifth Pair, or Trigeminus Nerves. 83, The Sixth Pair, or Motor Externus. 84. The Facial Nerve. 85, The Auditory — the two making the Seventh Pair. 36, 87, 33, The Eighth Pair of Nerves. (The Ninth Pair are not here seen.) 571. What are the cerebral ganglia ? 322 HITCHCOCK’S ANATOMY ganglia, the most important of which are the Thalami Optici, Corpora Striata, Olfactivc Ganglia, and Tubcrcula Quadrigc- mina. Fig. 308. 572. Spinal Cord.— Upon the an- terior portion of the Cerebellum, commences the Spinal Cord, the up- per portion of which, situated within the skull, is about three inches in length and one in breadth, and is called the Medulla Oblongata. 573. Ccrebro-Spinal Center.— These portions of the nervous sys- tem constitute what is known as the Cerebro-Spinal Axis or Center, and are all made up of two kinds of mat- The Cerebro-Spinal Axis seen Anteriorly. The Nerves have been cut through at a short distance from their Origin or central termination, a, The Cerebrum, b, Anterior Lobe of the Left Hemisphere of the Brain, c. Middle L(»be. <7, Posterior Lobe, al- most concealed by the Cerebellum, e, The Cerebel- lum. f, The Medulla Oblongata or Bulb. 1, First, or Olfactory Pair of Nerves. 2, Second Pair, or Optic. 8, Third Pair, or Motores Oculorum. 4, Fourth Pair, or Pathetic. 5, The Facial, or Fifth Pair. 6, Sixth Pair, or Abducentes. 7, Nerves of the Seventh Pair, or Facial ; also the Acoustic, or Portio Mollis, by some called the Auditory, and viewed as a division of the Seventh ; others call them the Eighth Pair. 9, The Glosso-Pharyngeal Nerves, called the Ninth Pair by some, by others the Anterior Division of the Eighth Pair. 10, The Pneurnogastric, by some in- cluded in the Eighth Pair, by others called the Tenth Pair. 11, Nerves of the Eleventh and Twelfth Pairs, the first being viewed by some as a Division of the Eighth Pair, and called Spinal Accessory; the latter, called by some the Ninth, by others the Twelfth, is the Motor Nerve of the Tongue. 13, Nerves of the Thirteenth Pair, or Sub-Occipital. 14, 15, 16, The First, Second, and Third Pairs of Cervical Nerves, g, Cervical Nerves form- ing the Brachial Plexus. 25, One of the Pairs of Nerves of the Dorsal Portion of the Si)inal Marrow. 83, One of the Pairs of Lumbar Nerves, h, Lumbar and Sacral Nerves forming the Plexus whence come the Nerves of the Lower Extremities, i and y. Ter inination of the Si)inal Marrow, called Canda Equina, Great Sciatic Nerve proceed- ing to the Lower Extremities. 572. What is tlie medulla oblongata? 573. What two kinds of matter does a slicing of the brain show, and how is the gray and white matter disposed? AND PHYSIOLOGY. 323 ter ; the gray or external, and the white or internal. This structure is best seen when the brain is cut through in a hori- zontal direction; the gray showing itself as an outside layer with an irregularly scolloped edge, while the white is internal, and constitutes the greater portion of the whole brain. 574. Blood-Vessels of the Brain— Venous Sinuses^ • — The blood-vessels of the brain are very numerous, since one sixth of all the blood is sent to this organ, although its weight is about one fortieth of the body. The arteries are the most numerous, and as already mentioned, those entering the head from the front side of the neck, communicate very freely with those coming in at the back side of the head, (see Fig. 213), making a perfect circle of communication, so that there may be no impediment to the cir- culation of the blood through the nervous center. The veins are not numerous. Some are found on the surface of the brain, but only a few pene- trate into its substance. But large channels are found be- tween the membranes called Sinuses, which do not pre- sent the ordinary characteris- tics of veins, except that they convey the blood to the heart. The two sinuses which are of the largest size, discharge their contents into the jugu- lar veins. (Fig. 309.) 575r Membranes of the Cere bro- Spinal Center. — Hura Mater. — Three mem- Fig. 309. Sinuses of the Base of the Skull. 1, Oph- thalmic Veins. 2, Cavernous Sinus, 3, Circular. 4, 6, Inferior Petrosal. 5, 9, Oc- cipital Sinuses. 7, Internal Jugular Vein. 574. What proportion of the blood goes to the brain? Which are the most numerous, the arteries or the veins ? What are the sinuses found there ? 324 HITCHCOCK’S ANATO:\[Y brancs envelop the brain, altliougli to the unassisted eye they appear as one. They are of great importance in the economy of the brain, and are often the seat of severe disease. The outer one is called the Dura Mater, that covers both the brain and spinal cord, and is attached firmly to tlic bones which it covers. It has the same composition as the liga- ments of the body — white fibrous tissue — and consequently is very tough, being the firmest of the three membranes. 576. Arachnoid Membrane —The Arachnoid Membrane lies directly beneath the dura mater, and receives its name from the Greek word signifying spider’s web. 577. Pi a Mater. — Closely beneath it is the Pia Mater, which lies directly upon the surface of the brain, and dips into all the cavities or convolutions on its surface. This membrane is especially serviceable in the nourishment of the brain, and receives the arteries which enter at the anterior and posterior part of the skull. Its nerves are branches of the sympathetic system. 578. Surface of the Brain. — The surface of the brain is very uneven, being covered with convolutions or tortuous ridges and corresponding depressions, the design of which is not as yet well known, though probably merely to procure a greater amount of surface, and they do not correspond to the irregularities on the surface of the skull from which phre- nologists profess to judge of character. 579. Ventricles of the Brain . — Within the brain are sev- eral cavities called ventricles, of which the special use has not been determined. (Fig. 305, p. 320.) It is a curious fact, however, that a post mortem examination of the brain of in- ebriates frequently discovers these cavities to be partially filled with alcohol. 580. Division of the Nerves. — All the nerves that pro- 575. How injiny membranes envelopin'^ the brain? Describe the dura mater. 576. Describe tlic arachnoid membrane. 577. Describe the pia Tnater. What are its nerves? 578. What is the connitlon of the surface of the brain ? 579. What are the cavities in the brain called ? 580. How arc all the nerves given off from the brain and spinal cord ? AND PHYSIOLOGY. ?25 ceed from the cerebro-spinal axis are given off in pairs on opposite sides of the median line of the body. They are di- vided into two sets ; those which are given oflf from the great brain, little brain, and medulla oblongata, being called cranial nerves^ and those from the spinal cord, spinal nerves. 581. Cranial Nerves, — Many of the cranial nerves, and all of the spinal nerves, arise by two roots, and soon form a small protuberance, which is called a Ganglion or knot, in which the fibers are confusedly mixed together, after which they proceed in the same sheath to their destination. 582. Of the cranial nerves there are twelve pairs, named as follows : First pair. . . .Olfactory. Seventh pair. .Facial. Second “ . . . .Optic. Eighth ..Auditory. Third “ ... . .Motores Oculorura. Ninth “ . . Glosso- Pharyngeal . Fourth “ . . . .Trochleares. Tenth “ ..ParYagi. Fifth “ . . . .Trifacial. Eleventh “ . .Spinal Accessory. Sixth .., . .Abducentes. •Twelfth “ . .Lingual. 583. Olfactory. — The olfactory nerves arise from the an- Fig. 310. A. View of the First Pair, or Olfactory, with the Nasal Branches of the Fifth. 1, Fron» tal Sinus. 2, Sphenoidal Sinus. 3, Hard Palate. 4, Bulb of the Olfactory Nerve. 5, Branches of the Olfactory on the Superior and Middle Turbinated Bones. 6, Spheno- palatine Nerves from the Second of the Fifth. 7, Internal Nasal Nerve from the First of the Fifth. 8, Branches of Seven, to Schneiderian Membrane. 9, Ganglion of Cloquet KwWio, foramen inciHivium. 10, Anastomosis on the Inferior Turbinated Bone of the Branches of the Fifth Pair. What are the two principal groups of nerves? 581. How many roots do most of the nerves have ? 582. How many pairs of cranial nerves, and what are their names ? 320 HITCHCOCK’S ANATOMY terior portion of the base of the brain, and are distributed upon the mucous membrane of the nostrils ; especially that part of it which is spread out upon the turbinated bones. Fig, 311. A View of the Second Pair or Optic, and the Origin of Seven other Pairs. 1, 1, Globe of the Eye. The one on the left hand is per- fect, but that on the right has the Sclerotic and Choroid removed to show the Ketina. 2) The Chiasm of the Optic Nerves. 3, The Corpora Albicantia. 4, The Infundibulum. 5, The Pons Varolii. 6, The Medulla Ob- longata. The figure is on the Right Corpus Pyramidale. 7, The Third Pair, Motores Oculi. 8, Fourth Pair, Pathetici. 9, Fifth Pair, Trigemini. 10, Sixth Pair, Abducentes. 11, Seventh Pair, Auditory and Facial. 12, Eighth Pair, Pneumogastric, Spinal Acces- sory, and Glosso-Pharyngeal. 13, Ninth Pair, Hypoglossal 584. Optic . — The optic nerves arise at a point be- hind that where the olfac- tories are given off, and about one inch from this point come together and form a ganglion ; after this they are again separated and proceed to the posterior portion of each eye-ball^ where they are expanded into a membrane, called the Ketina. (Fig. 311.) 585. Motores OculoruHi. — The third are also given off from the base of the brain near to the pons varolii, and are sent to a part of the muscles of the eye. 586. Troclileares — The trochleares have nearly the same origin as the last-men- tioned pair, and are distrib- uted to the superior oblique muscles of each eye. (Fig. 312.) 587. Trifacial.— The fifth pair, or is the largest of the cranial nerves. It is analogous to the spinal nerves in Give the anatomy of the olfactory nerves. 584. Describe the optic nerves. 555. Describe tlio motores oculorum. 686. Give the anatomy of the fourth pair. 687. De- Borlbo the trifacial. AND PHYSIOLOGY. 327 A View of the Third, Fourth, and Sixth Pairs of Nerves. 1, Ball of the Eye, the Rec- tus Externus Muscle being cutand hanging down from its origin. 2, The Superior Max- illa, 8, The Third Pair, or Motor Oculi, distributed to all the Muscles of the Eye except the Superior Oblique and External Rectus. 4, The Fourth Pair, or Patheticus, going to the Superior Oblique Muscle. 5, One of the Branches of the Fifth. 6, The Sixth Pair, or Motor Externus, distributed to the External Rectus Muscle. 7, Spheno-Palatine Ganglion and Branches. 8, Ciliary Nerves from the Lenticular Ganglion, the short Root of which is seen to connect it with the Third Pair. A View of the Distribution of the Tri- facial, or Fifth Pair. 1, Orbit. 2, Antrum of Highmore. 3, Tongue. 4, Lower Max- illa. 5, Root of Fifth Pair, forming the Ganglion of Casser. 6, First Branch, Oph- thalmic. 7, Second Branch, Superior Maxillary. 8, Third Branch, Inferior Maxillary. 9, Frontal Branch, dividing into External and Internal Frontal at 14. 10, Lachrymal branch, dividing before en- tering the Lachrymal Gland. 11, Nasal Branch. Just under the figure is the long Root of the Lenticular or Ciliary Ganglion, and a few of the Ciliary Nerves. 12, In- ternal Nasal, disappearing through the Anterior Ethmoidal Foramen. 13, Exter- nal Nasal. 14, External and Internal Frontal. 15, Infra-Orbitary Nerve. 16, Posterior Dental Branches. 17, Middle Dental Branch. 18, Anterior Dental Nerve. 19, Terminating Branches of In- fra-Orbital, called Labial and Palpebral. 20, Subcutaneous Mal{e,or Orbitar Branch. 21, Pterygoid or Recurrent, from Meckel's Ganglion. 22, Five Anterior Branches of Third of Fifth, being Nerves of Motion, and called Massoter, Temporal, Ptergoid, and Buccal, 23, Lingual Branch joined at an acute angle by the Chorda Tympani. 24, Inferior Dental Nerve terminating in 25, Mental Branches. 26, Superficial Temporal Nerve. 27, Auricular Branches. 28, Mylo-hyoid Branch. Fig. 313. 328 HITCHCOCK’S A N A T O Y Fm. 314. Distribution of the Fifth Pair of Nerves, a, Submaxillary Gland. 1, Small Root of the Fifth Nerve. 2, Gasserian Ganglion. 8, Ophthalmic Nerve. 4, Upper Maxillary Nerve. 5, Lower Maxillary Nerve. 6, Chorda Tympani. 7, Facial Nerve. that each nerve arises by two roots, and afterwards, before distribution, forms the Gasserian ganglion. This ganglion is separated into three branches : the ophthalmic, which supplies 315. the region of the eye and nose ; the superior maxil- lary, supplying different parts of the face from the temporal muscle to the A View of the Origin and Disiribu- tion of the Portio Mollis of the Sev- enth Pair, or Auditory Nerve. 1, The Medulla Oblongata. 2, The Pons Var- olii. 8, 4, The Crura Cerebelli of the Right Side. 5, Eighth Pair. 6, Ninth Pair. 7, The Auditory Nerve distrib- uted to the Cochlea and Labyrinth. 8, The Sixth Pair. 9, The Portio Dura ef the Seventh Pair. 10, The Fourth Pair. 11, The Third Pair. AND PHYSIOLOGY. 329 Pig. 316. lips, including the upper teeth and the inferior maxillary, sending its branches to the tongue, cheeks, and anterior portion of the face. 588. Abducentes. — The sixth pair, abducentes^ are sent from the medulla oblongata to the external muscle of the eye. 589. Facial. — The facial nerves have their origin in common with the last pair. They join with some of the branches of the fifth pair, and distribute their filaments to some of the muscles of the face. 590. Auditory. — The au- ditory nerves^ as their names imply, are sent to the ear. They enter the internal ear Origin and Distribution of the Tenth Pair of Nerves. 1, 3, 4, The Medulla Ob- longata. 1 Is the Corpus Pyramidale of one side. 3, The Corpus Oblivare. 4, The Corpus Restiforme. 2, The Pons Varolii. 5, The Facial Nerve. 6, The Origin of the Glosso -Pharyngeal Nerve. 7, The Gang- lion of Andersch. 8, The Trunk of the Nerve. 9, The Spinal Accessory Nerve. 10, The Ganglion of the Pneumogastric Nerve. 11, Its Plexiform Ganglion. 12, Its Trunk. 13, Its Pharyngeal Branch forming the Pharyngeal Plexus (14), as- sisted by a Branch from the Glosso- pharyngeal (8), and one from the Superior Laryngeal Nerve (15). 16, Cardiac Branch- es. 17, Recurrent Laryngeal Branch. 18, Anterior Pulmonary Branches. 19, Posterior Pulmonary Branches. 20, Esophageal ‘Plexus. 21, Gastric Branches. 22, Origin of the Spinal Accessory Nerve. 23, Its Branches distributed to the Sterno-Mastoid Muscle. 24, Its Branches to the Trapezius Muscle. 5S8. Describe the abducentes. 589. Describe the facial nerves. 590. Describe the au- ditory nerves. 030 HITCHCOCK’S ANATOMY after receiving fibers from the facial, and there divide into two branches, which are distributed in the irregular labyrinth of the ear. 591. fi 1 0 s s 0 - P li a r y n g e a I . — The glosso-pharynjcal makes the ninth pair, and is sent to the mucous surface of the fauces, tongue, tonsils, and mucous glands of the mouth. 592. Par Vagi, or Pneumogastric.— The tenth pair, vagum^ spring from the medulla oblongata, and after giv- ing branches to several of the cranial nerves, are dis- tributed upon the heart, lungs, stomach, and nearly all the organs of the tho- rax and abdomen. 593. Spinal Accessory. — The spinal accessory takes its origin from the The Anatomy of the side of the Neck, showing the Kerves of the Tongue. 1, A Fragment of tlie Temporal Bono containing the Meatus Auditorius Ex- ternus, Mastoid, and Styloid Process. 2, The Stylo-Hyoid Muscle. 3, The Stylo-GIossus. 4, The Stylo-Pharyn- geus. 5, The Tongue. 6, The Hyo- Glossus Muscle; its two portions. 7, The Genio-Hyo-Glossus Muscle. 8, The Genio-Hyoideus : they both arise from the inner surface of the Symphy- sis of the Lower Jaw. 9, The Sterno- Hyoid Muscle. 10, The Sterno-Thyroid. 11, The Thyro-Hyoid, upon which the Thyro- Ilyoidean Branch of the Hypoglossal Nerve is seen ramifying. 12, The Omo-Hyoid crossing the Common Carotid Artery (13), and Internal Jugular Vein (14). 15, The Ex- ternal Carotid giving olf its Branches. 16, The Internal Carotid. 17, The Gustatory Nerve giving off a Branch to the Submaxillary Ganglion (18), and communicating a little further on with tne Hypoglossal Nerve. 19, The Submaxillary, or Wharton's Duct, , jiassing forwards to the Sublingual Gland. 20, The Glosso-Pharyngeal Nerve, passing in behind the Hyo-Glossiis Muscle. 21. The Hypoglossal Nerve curving around the Oc- ci[>ital Artery. 22, The Descendens Noni Nerve, forming a Loop with (23) the Coinmu- nicans Noni, which is seen to be arising by filaments from the Upper Cervical Nerves. 24, The Pneumogastric Nerve, emerging from between the Internal Jugular Vein and Common Carotid Artery, and entering the Chest. 25, The Facial Nerve, emerging from the Stylo-Mastoid Foramen, and crossing the External Carotid Artery. Pig. 317. Describe the glosso-pharyngoal, par vagum, and spinal accessory. AND PHYSIOLOGY. 331 upper part of the spinal column, and afterwards enters the cranium. After keeping company with the par vagum for a part of its course, it is distributed to some of the muscles upon the head and face. 594. Lingual. — The Ungual nerve plunges its branches deeply into the fibers of the tongue, and communicates with a branch of the trifacial. 595. Spinal Cord, — The spinal cord is that portion of the cerebro-spinal axis contained within the channel made by the foramina, or openings of the verte- bra. It extends from the medulla ob- longata just at the base of the skull, to the second lumbar vertebra, and has an average diameter of half an inch. It Portion of the Spmai Cord, o niul Origin of one Pair of has the general appearance of a flattened Nerves. «, spinai cord. &, cord, but on a closer inspection it ap- interior Root. Trunk pears to be made up of two smaller cords, forced by both. /, Branch, called the lateral cords, nearly separated by two clefts, called the anterior and posterior median fissures. This cord is not perfectly uniform in its size, but presents two enlargements, one at the point where the nerves are given oS* to the upper extremities, and the other near the lower end of the cord. Fig. 318. 596. Microscopic Structure of the Spinal Cord.— In anatomical structure we find the spinal cord and spinal nerves are made up of two kinds of nervous matter, the white and the gray, and also that each pair of these nerves arises by an anterior and a posterior root. The posterior root is made up of gray nervous tissue, and is called the sensitive root, since it gives the sense of feeling to the parts where it is dis- tributed ; the anterior root of white fibers is called the mo- tor root, because it imparts motion to the different muscles of 594. Describe the lingual. 595. What is the spinal cord ? Uow many fissures has the spinal cord? How many enlargements? 596. What is the microscopic structure of the spinal coni? Which is the sensitive and which the motor root? 332 HITCHCOCK’S ANATOLIY the body. A ganglion is found upon the posterior root, just before it unites with the anterior. 597. Origin of the Spinal Nerve s— Between each of the vertebrae the spinal nerves are given off. These arc made up of fasciculi, and each fasciculus of distinct fibers which somewhat resemble muscular fiber. They arise on each side of the cord by two roots, one given off from the anterior and the other from the posterior part of the lateral cords ; the anterior root being the one that is designed to produce mo- tion, and the posterior giving sensation to the parts on which it is distributed. These two roots unite as soon as they have fairly left the spinal cord, after which they proceed as a single nerve. (See Fig. 318.) Fig. 319 . 598 . Groups of Spinal Nerves —These nerves are grouped together, and have the same name as the groups of verte- brae in which they are located. 8 Cervical. 6 Lumbar. 12 Dorsal. 6 Sacral. The last nine are additional, or supple- mentary to the spinal cord, and not prop- erly a portion of it. They are called the cauda equina. 599. Plexuses . — Most of these nerves are grouped together soon after leaving Diagram to show the De. Spinal column, each group being cassation (crossing from called a plcxus (from the Greek to side 10 side) of Nerve Fi- n\ i i i bers in a Nerve. wcave''), which IS Simply a net-work of nervous fibers. Although there is to the naked eye a com- plete interlacement and an apparent loss of fiber, yet by the microscope these fibers can be distinctly traced through the whole mass, with the exception of a few which are inter- changed for purposes to be described hereafter. After emerg- r/iZ. Give the origin of the spinal nerves. 598. State the groups of the spinal nerves, 599. Describe the nature of the plexuses. AISTD PHYSIOLOGY 333 Fig. 320. Nervous System. a, Brain. Little Brain, c, Spinal Marrow, d, Facial Nerve, e, Brachial Plexus, caused by the union of several Nerves coming from the Spinal Marrow, f, Median Nerve. g, Cubital Nerve. A, Internal Cutaneous Nerve of the Arm. i, Kadial and Musculo- cutaneous Nerve of the Arm. Intercostal Nerves, Femoral Plexus. ^ Sciatic Plexus, w, Tibia! Nerve, n, External Peroneal Nerve ; o, External Saphenous Nerve. 334 HITCHCOCK’S ANATOMY ing from the plexuses, the nerves proceed to their destination and receive names, many of which are the same as the arteries which they accompany. 600. Cervical Plexus — Brachial Plexus — Lumbar Plexus — Sacral Plexus . — The cervical plexus is made up of the four upper cervical nerves, and the brachial plexus of the Fio. 321. Fia 322. A View of the Brachial Plexus of Nerves and Branches of Ann. 1, 1, The Scalenus Anticus Mus- cle, in front of which are the Roots of the Plexus. 2, 2, The Median Nerve. 3, The Ulnar Nerve. 4, Nerves of Front of Fore- Arm. The Branch to the Biceps Muscle. 5, The Nerves Median Nerve. 2, Anterior Branch of Wrisberg. C, Tlie Phrenic Nerve from the of Musculo-Spiral or Radial Nerve. Third and Fourth Cervical. 8, Ulnar Nerve. 4, Division of Me- dian Nerve in the Palm to the Thumb, First, Second, and Radial Side of Third Finger. 5, Division of Ulnar Nerve to Ulnar Side of Third and both Sides of Fourth Finger. COO. What nerves go to make up the cervical and brachial plexus? AND PHYSIOLOGY. 335 four lower cervical and upper dorsal nerves, and they give off their branches to the upper part of the body. The lumbar plexus is made up of the last dorsal nerve and the five lumbar nerves ; and the sacral plexus of a branch of the last lumbar and the upper sacral nerves. These supply the portions of the body below the loins, and the superficial parts of the body between the loins and upper part of the chest. Fig. 323. A View of the Branches of the Ischiati# Plexus to the Hip and Back of the Thigh. 1, 1, Posterior Sacral Nerves. 2, Nervi Glutei. 3, The Internal Pudic Nerve (Nervus Pudendalis Longus Superior). 4, The Lesser Ischiatic Nerve, giving off the Perineal Cutaneous (Pudendalis Longus Inferior), and 5, The Eainus Femoralis Cutaneous Posterior. The reference to the Great Ischiatic has been omitted. It is seen to the right of 3. and Branches. 1, Place of emergence Division of tho Nerve into Branches. Branches of Obturator Nerve. Fig. 324. A View of the Anterior Crural Nerve of the Nerve under Poupart’s Ligament. 2, 3, Femoral Artery. 4, Femoral Vein. 5, 6, Nervus Saphenus. Describe the lumbar and sacral plexus. 15 . ^ 336 HITCHCOCK’S ANATOMY 601. Direction of the Nerves. — The largest and most im- portant nerves follow the same general direction as the larger blood-vessels, and generally are in close proximity to them. 602. Motor Nerves — Mode of Termination — Pacinian Corpuscles. — The nerve fibers which go from the anterior columns of the spinal cord terminate in the fleshy portions of the muscles, because they are the motor nerves, or those ex- FiGr. 325. Pig. 326 A View of the Termination of the Posterior Tibial Nerve in the Sole of the Foot. 1, Inside of the Foot. 2, Outer Side. 8, Heel. 4, Internal Plantar Nerve. 5, Exter- nal Plantar Nerve. 6, Branch to Flexor Brevis. 7, Branch to Out- side of Little Toe. 8, Branch to Hjtace between Fourth and Fifth Toes. 9, 9, 9, Digital Branches to rernainin; Spaces. 10, Branch to Internal Side of Great Toe. Pacinian Corpuscles. A, Single Corpuscle highly Magnified, a, Its Peduncle. 5, Its Nerve Fiber, c, Outer Layers, and d. Inner Layers of the Capsule, e, Nerve Fibers, and /, Its Subdi- vision and Termination. B, Portion of Digital Nerves, with Pacinian Corpuscles attached. 001. Give the general direction of the nerves through the body. G02. Where do the motor nerves terminate? AND PHYSIOLOGY. 8o7 citing motion. Those from the posterior columns spread through the surface of the body, giving sensation to the skin. The mode, however, in which they terminate is not always the same. As far as at present is known, they seldom terminate in a free or single extremity, but in loops, returning into themselves, or joining with other fibers. And it is an an- atomical fact that the nerve tubes do not anastomose one with the other, as is the case among the blood-vessels ; but each tube discharges its own duty, and not that of another under any circumstances. In the skin of the hand and foot they terminate in minute oval bodies from the rlith to the TTo^b of an inch in length, and from one twenty-sixth to one twentieth of an inch in breadth, called Pacinian Cor- puscles (from Pacini, their discoverer), and are attached to the branches and extremities of the nerves very much in the same manner as some kinds of fruit are attached to their boughs. (Pig- 326.) Of these, there are about six hundred in the hand and a somewhat smaller number in the foot. They are composed of connective or areolar tissue in from twenty to sixty bands, with interspaces containing a serous fluid, and are attached to their nervous twig by a rounded peduncle. The function of these bodies is entirely unknown. 603. Sympathetic System — Its Size — Connection with Spinal Nerves — Destination of its Branches. — Besides the cerebro-spinal center, there is another organi- zation of nervous tissue which is called the Sympathetic Nerve, or Ganglionic System, and is to be regarded as an appendage of the spinal nerves. It is of very limited size, consisting of mere reddish threads of nervous matter and oval bodies called ganglia, never so large as peas. These ganglia and nerves extend along each side of the spinal column from State the inanncr in which they terminate. Give a description of the Pacinian cor- puscles. 603. What is said of the structure of the sympathetic system ? 338 II T T C It C O C K ’ S ANATOMY Fio. 327. tlio atlas to tlic coccyx, communicating with all the spinal nerves hy two small fibers (see Fig. 328), and giving branches to all the internal organs and viscera. Branches and ganglia are also found between the bones of the cranium and the face. The branches which are given olf to the internal organs accom- pany the arteries to the same, forming a net- work Great Sympatlietic Nerve. 1, Plexus on the Carotid Artery in the Carotid Foramen. 2, Sixth Nerve (Motor Externus). 3, First Branch of the Fifth, or Ophthalmic Nerve. 4, A Branch on the Septum Narium going to the Incisive Foramen. 5, Recurrent Branch, or Vidian Nerve dividing into the Carotid and Petro- sal Branches. 6, Posterior Palatine Branches. 7, Lingual Nerve joined by the Chorda Tympani. 8, Portio Dura of the Seventh Pair. 9, Supe- rior Cervical Ganglion. 10, Middle Cervical Ganglion. 11, Inferior Cer- vical Ganglion. 12, Boots of the Great Splanchnic Nerve arising from the Dorsal Ganglia. 13, Lesser Splanchnic Nerve. 14, Eenal Plexus. 15, Solar Plexus. 16, Mesenteric Plexus. 17, Lumbar Ganglia. 13. Sacral Ganglia. 19, Vesical Plexus. 20, Rectal Plexus. 21, Lumbar Plexus (Cerebro-Spinal). 22, Rec- tum. 23, Bladder. 24, Pubis. 25, Crest of the Ilium. 26, Kidney. 27, Aorta. 28, Diaphragm. 29, Heart. 80, Larynx. 31, Submaxillary Gland. 32. Incisor Teeth. 33, Nasal Sep- tum. 3i, Globe of the Eye. 35, 36, Cavity of the Cranium. Where does it give Its branches? AND PHYSIOLOGY. 339 Fig. 328. c, c, Anterior Fissure of the Spinal Cord, a, Anterior Root, j), Posterior Root, with its Ganglion, a', Anterior Branch, p', Posterior Branch, s, Sympathetic, e. Its Double Junction with the Anterior Branch of the Spinal Nerve by a White and Gray Filament. of communication around the vessels. And as all the inter- nal organs, especially those called vital, are supplied with this nerve, and not directly from the cerehro-spinal center, it is hence called a nerve of organic life. 604. Sympathetic Ganglia. — Each of these ganglia may be considered as a nervous center sending forth strands in three directions ; 1st, to join the spinal nerves in their dis- tribution ; 2d, to the spinal cord itself ; 3d, to the next sym- pathetic ganglion above. 604. What may each of these ganglia bo considered as ? 340 HITCHCOCK’S ANATOMY 605. Groups of Sympathetic Ganglia.— These ganglia are grouped together according to the locality, to which their branches are distributed. Thus we have the Cranial ganglia, Cervical ganglia, Thoracic ganglia. Lumbar ganglia, and Sacral ganglia. Besides these there are several large plex- uses which have received distinct names, although a great number of small ones have not received any names. Of the most important ones we may name the Pharyngeal, in the immediate vicinity of the Pharynx, the Cardiac lying upon the heart, and the Solar, between the liver and stomach, or, as is more commonly known, the pit of the stomach. 606. The Solar Plexus. — The Solar Plexus seems to be, as its name implies, a sun or center for nervous power to the intestines, since branches from this plexus accompany the ar- teries to the vital organs, where they subdivide again and again, and enter their coats and substance. FUNCTIONS OF THE NERVOUS SYSTEM 607. The functions of the Nervous System are the most important and delicate of any in the body. 1. The Brain affords a seat and center for life and intellect. 2. The nerves are inlets for all the senses to the sensorium or seat of sensa- tion. 3. They are the medium of all the movements of the body, voluntary and involuntary. 4. They establish and maintain a sympathy between all the parts of the body, and equalize all the vital forces. 5. They preside over the in- voluntary functions, such as the circulation of the blood, di- gestion, respiration, and reflex actions. 608. Inlcllect and Will located in the Brain.— Voluntary Movements dependent on the Brain. — The whole Brain not essential. — The Intellect and O'lr*. How arc the syinjmtlictlo {ranglla {^rouped together? What is said of the syrn- j)at,hctlc i)lexu8CH? (i(Mh Describe the solar plexus, 607. What are the five principal func- tions of the nervous system ? AND PHYSIOLOGY. 341 Will evidently reside in the brain (cerebrum), and re- quire that this organ should be in a healthy state, since, if any disease affects its whole substance, their power is destroyed. Voluntary muscular movements depend on a sound and healthy brain, although reflex movements, and the motion necessary to sustain animal life, are often carried on in some animals for a considerable time, when they are born without a brain. But the whole brain does not seem to be absolutely essential to life and mental operations, for many instances are mentioned, where a considerable portion of the brain has been removed by accident, such as a bullet or iron bar being shot through the head followed by a discharge of nervous matter : and yet the persons have lived for years subsequent to the accident in as sound a condition as ever. 608a. Necessity of two Cerebral Hemispheres —One may be injured, and not the other. — The reason of the division of the brain into lobes or hemispheres is not so easily understood. Perhaps it may be that so large an organ of so soft a substance could not easily sustain its own weight, es- pecially when reclined on one side, and at the same time properly perform its functions. A more probable reason, however, is this. It is a well-known fact, that one of the hemispheres may be diseased or injured, so as to perform its functions imperfectly, and yet the other hemisphere be in its ordinary healthy state. Also one hemisphere may be so much afiected, that the opposite side of the whole body is paralyzed in motion or sensation, or both. It then seems reasonable to suppose, that, since the brain would be so liable to injuries, it was made in two portions, so as to prevent the entire destruction of life by an injury to one of the hemi- spheres. 608. Where are the intellect and the will located ? What movements depend on the brain ? Is the whole brain absolutely essential for intellection ? 608 ii. Why are there probably two hemispheres to the brain? 342 HITCHCOCK’S anatomy 609. To secure Precision in all Voluntary Actions. — In Draper’s Physiology is found another hypothesis for the division of the brain into two parts : this is to secure precision in the efforts of the intellect and will. For there is no doubt/^ he says, ^‘that the hemispheres have not only the power of acting separately, but also conjointly ; thus there is no student but must have observed, when busily engaged in reading, that his mind will wander off to other things, though he may mechanically cast his eye over page after page ; and the same may occur in listening to a lecture or sermon. But though the insane man may indulge in two synchronous trains of thought, he never indulges, in three, for the simple reason that he has not three hemispheres to do it with, the same re- mark applying to the sane man in the accidental wandering of his thoughts.’’ 610. Tlioiiglit, Memory, and the Reasoning Powers require a Sound Brain. — As already mentioned, the brain is not the seat of motive power : this does not originate here, although voluntary movements are controlled by it. But automatic or reflex movements, such as the twitching of the muscles of the leg and foot, when the sole of the foot is tickled with some slightly irritating substance, are entirely beyond the control of the cerebrum or will, since they take place nearly as well in a person who is asleep or stunned by a blow, or even when the nerves of sensation and motion are paralyzed. Thought, memory, reasoning, and all the intel- lectual states demand a healthy and a sound brain for their perfect action, while the ordinary muscular movements and the functions of respiration, circulation, and digestion, are dependent upon the Spinal Cord, Sympathetic Nerve, and Cerebellum. 611. Definition of Sleep. — Need of Sleep. — Sleep, ‘Hired nature’s sweet restorer,” is a state of the body, in COI). can two lu‘inisi>lierc8 scciiro a precision in voluntary actions ? 610. Aro reflex movements under tlio control of tho bruin? What powers of mind aro dei)endent on tho cerebrum ? AND PHYSIOLOGY. 843 ■which there is a more or less perfect suspension of the activ- ity of the brain. The functions of digestion, secretion, and respiration, proceed during the soundest sleep, though with less activity than during the wakeful state. In many cases, however, the functions of the brain do not entirely cease, as is seen in the phenomena of dreaming, where the brain seems to be actively at work, but the senses and animal functions are quiescent. Sleep is demanded by all animals to procure rest to the different organs of the body, and in health it comes to all, though in different degrees of soundness, but generally the greater the exhaustion, the more complete the sleep. 612. Periodical Tendency of Sleep— The Will can for some Time overcome Sleep. — The tendency to sleep is periodical. All persons feel an inclination to sleep during some portion of the twenty-four hours, and during the night, if health be good and nature not perverted. Some strong intellectual effort, however, or some powerful emotion, will overcome drowsiness for a long time, as in the case of the student working out a difficult problem, or a mother watching her sick child. But when the problem is mastered, and the child has safely passed the crisis, sleep comes on with irresist- ible force. Cases occur constantly to show that the brain must have its repose in spite of intellectual effort or danger. It is related that boys wearied out with continued labor in the battle of the Nile, slept during a part of the action, and in another naval engagement, a captain slept two hours within a yard of his largest gun, which was kept in action during the whole time. Indians at the stake of torture will sleep on the least remission of agony, but awake as soon as it is renewed again. And we learn that a most barbarous punishment is still practiced in China, that of keeping a victim awake until he dies of sheer exhaustion. The distress of it is said to be terrible. 611. What is sleep? What powers are inactive (luring sleep, and what processes are carried on during it? What is sleep necessary for? 612. State the fact of a periodical tendency to sleep. Can the will overcome sleep? For how long a time can it do it ? Eelate the facts mentioned. 15 * 344 HITCHCOCK’S ANATOMY 613. Inducements to Sleep— Sleep sometimes under the Control of the Will. — Ordinarily darkness and si- lence promote sleep ; but if a person once becomes habituated to noise during slumber — if it be a continuous one — he can not sleep well without it. Thus persons living in the vicinity of forges and noisy mills can not readily sleep elsewhere. And a monotonous repetition of sounds is a most favorable provo- cative to sleep, the cause of which is that other impressions can not so readily be made on the mind, and thus the sleeper is less easily roused. A dull reader on a dull subject has a most ready eflFect in producing sleep, as well as the sound of a distant waterfall, or the rustling of leaves in a forest. Rub- bing many parts of the skin, or combing the hair by another person, 'will often cause drowsiness, and sometimes sleep. Again a person can sometimes put himself to sleep, if restless, by a monotonous intellectual effort, such as the rehearsal of a Latin paradigm, or counting the rain-drops, as they fall from the eave trough into the spout. 614. Effect of Habit on Sleep. — The effect of habit is powerful in producing sleep. Let one be accustomed to retire early — in accordance with nature — and sleepiness comes at the usual hour for retiring ; but if a person for a series of years is in the habit of sleeping the latter part of the night and early in the morning, it is almost impossible for him to sleep early in the night. Those persons who, like sailors, soldiers, and watchers, are obliged to catch sleep when they call get it, and then only in small amounts at a time, sleep with but little difficulty when the opportunity presents itself. Captain Barclay, who walked one thousand miles in as many consecutive hours, had such a* power over himself, that he was asleep the moment he lay down. Some physicians have the same power. CIO. What arc tho common inducements to sleep? Do any persons ever require a noise, in order to sleep soundly ? What effect does rubbing or chafing certain parts of tho body have upon sleep? Can sleep over be brought about by an action of the will? How ? 614. What effect has habit upon producing sleep ? Mention the case of Captain liarclay. AND PHYSIOLOGY. 345 615. Preventives of Sleep. — Any unusual noise or place of sleeping will prevent or disturb the sleep of many persons. Thus the singing of a mosquito keeps many a man awake a long time. But if a noise be repeated often, it will have no effect of this kind. The college Freshman for the few first mornings is readily awaked by the first stroke of the early prayer-bell, but in a short time it has no effect w^hatever. A gentleman who had taken his passage on board a man of war, was aroused on the first morning by the report of the morning gun, which chanced to be fired just above his head ; the shock was so violent as to cause him to jump out of bed. On the second morning he was again awakened, but this time he merely started and sat up in bed ; on the third morning the report had simply the effect of causing him to open his eyes for a moment and turn in his bed ; on the fourth morn- ing it ceased to affect him at all, and his slumbers continued to be undisturbed so long as he remained on board.” 616. An Absence of Accustomed Sounds prevents Sleep. — The reverse of this sometimes happens, if there be a cessation of monotonous and unaccustomed sound, by which sleep was induced. Thus a person who has been read or preached to sleep, will awake if the reader or preacher pause or stop, before any disturbance is made, and a person asleep in a railway train, will often awake on the stopping, or even on the slackening of the train. 617. Amount of Sleep. — The amount of sleep necessary for man, varies exceedingly, being affected by the conditions of age, temperament, habit, and exhaustion. Infants and very old people sleep the most. The former require it that the constructive process may go on as uninterruptedly as possible, and they generally sleep three fourths of the time. The latter need a large amount of sleep, because the vital energies are so feeble. 615. What -will often easily prevent sleep ? Instance the college Freshman and the gentleman on the man of war. 616. How does an absence of accustomed sounds affect sleep ? 617. What amount of sleep is necessary ? What ages sleep the most ? 346 HITCHCOCK’S ANATOMY 618. A lymphatic Temperament a Sleepy one, — Persons of a lymphatic temperament, those who are seldom excited, sleep more than those of a nervous temperament, who are always rapid and quick in their movements. The former live slowly, and but comparatively little waste is going on, and consequently the brain is all the time nearer to sleep than in the latter class, whose brain, when awake, is very active, and when asleep, is asleep very soundly. 619. Effect of Habit on the Amount of Slcep.~Rc- markable Cases. — The amount of sleep is greatly modified by habit, and often the briefest sleepers have been men of the greatest activity. If a person acquire the habit of sleeping but little, he must sleep very profoundly, so that what is lost in quantity, is made up in intensity. The habit of taking but little sleep, however, is not a sure indication that a proper amount of it has been secured. Frederic the Great, and J ohn Hunter slept but five hours out of the twenty-four ; and General Elliot, engaged in the defense of Gibraltar, and Na- poleon, often slept but four hours out of the twenty-four. •The general rule, however, seems to be that man should take from six to eight hours of the twenty-four, for uninter- rupted slumber. Women in general seem to require rather more. 620. Mode of Access of Sleep. — To some sleep comes on instantly when the will determines upon it, but to others it is a gradual and tedious process, especially in ill health, or an excited mental state. Many physicians drop asleep as soon as the head touches the pillow, and are aroused by no ordinary sound, such as the tread of another person in the room, or the shutting of a door, but wake as soon as the night-bell is rung. Sir E. Codrington, when a young man in the naval service, was very active at one time in looking out for signals. CIS. Wliat aro tho sleepy ternporamonts ? What the wide-awake ones ? G19. How* does liabit alFect tho amount of sleep ? State some remarkable cases. What is an average amount of sleep for men ? How muoli forwomon? G20. How does sleep come on> Give oxamplea. AND PHYSIOLOGY. 347 and was employed during his waking hours in this business. Hence his sleep was very solid, and he was roused by no or- dinary sound, but his comrades amused themselves by whis- pering the word ^^signaP’ in his ear, when he was at once aroused and fit for duty. 621. Functions of the Cerebellum. — The Cerebellum does not seem to be in any manner directly connected with the phenomena of mind. But it seems designed simply for the purpose of combining the actions of different muscles, or presides over the coordination of voluntary muscular move- ments, as in walking, speaking, and similar actions requiring several sets of muscles to be used at the same instant. Ac- cordingly in animals, which possess the greatest variety of movements, we find the largest cerebellum. 622. Effects when Removed from Animals. — The Con- trolling Power of Muscular Motions. — ^When this organ has been removed from some of the lower animals, it was found that they could not control their movements. When laid down they could not recover their erect posture, and when threatened with a blow, they in vain endeavored to avoid it. Another phenomenon attending a wound, or removal of both sides of the cerebellum, was the motion of the animal in a backward direction, and the rolling firom side to side on the longitudinal axis of the body, and keeping up this motion uninterruptedly, for several hours, at the rate of sixty revolu- tions per minute. In some men who have been afflicted with a disease of this organ, an unsteadiness of gait has been ob- served, which gives additional strength to the belief that the Cerebellum is the regulator of muscular movemeuts. 623. Functions ot the Medulla Oblongata.— The Me- dulla Oblongata seems to have for its function the sending of nervous power to the muscles of respiration and swallowing. 621. Does the cerebellum control the phenomena of mind? What are its functions’ 622. What effects does its removal cause in animals ? How does a disease of it affect men ? 623. What operations are controlled by the medulla oblongata ? 348 niTc II cock’s anatomy or, in other words, respiration and deglutition arc controlled and performed by the medulla oblongata. 624. Function of the Cerebral Ganjilia. — The scries of Ganglia, Corpora striata, Thalami optici, etc., are regarded by Dr. Carpenter as the true sensorium in man, and this is one of the most important facts established with regard to the nervous system. A prominent reason for the belief, that the brain is simply superadded to them, is seen in many instances of children born without a brain, but with the sensory ganglia present, where the functions of animal life have been carried on for a considerable length of time. 625. Functions of the Spinal Cord. — The functions of the Spinal Cord are considered in a double aspect : First, as the means of communication between the roots of the spinal nerves, and those parts of the nervous system within the cranium, and second, as a center of nervous power to pro- duce reflex movements when an impression is made upon this cord. 626. Function of Sympathetic Nerve.— The Sym- pathetic Nerve ‘4n its offices is a motor nerve to many of the internal viscera of the body, the heart and the intestinal canal especially ; it is also a sensitive nerve to these parts, and it presides over the action of the blood-vessels of these as well as of the other parts, wffiere it is distributed, as of the head and neck, and likewise of all the principal glands of the body.’’ 627. Organic Functions depend on the Spinal Cord.— Effect of Pressure on this Cord. — Almost all the func- tions of organic life, such as breathing, digestion, and circu- lation, are greatly influenced by the condition of the spinal cord, and especially in its connection with the sympathetic nerve, although the brain has some controlling power. Yet 0*24. liy what set of bodies are the principal functions of animal life carried on? 625. What arc the functions of tlic spinal crain ? 6‘29. What theory lias been olTered for the use of the ganglia? 630. What thrcti groups of the cervical nerves are Loro given? 631-640. State the function of each pair of the cranial nerves. Olfactory. Optic. Auditory. Motores Oculorum. Patheticus. Abducentes. Facial. Lingual. Trifacial. Glosso-Ph aryngeaL Par Yagum. Spinal Accessory. AND PHYSIOLOGY. 351 632. The optic nerve, as expanded in the retina, is the nerve of sight. 633. The auditory nerve receives the vibrations of the air, which produce sound. 634. The motores oculorum, pathetici, and abducentes are the nerves which furnish motive power to the eye-ball. 635. The facial nerve is distributed to the muscles of the face, and is the one that aids in the expressions of the emo- tions and will, as exhibited in the countenance. It is also the channel of the reflex actions in respiration, as when a person involuntarily gasps if cold water be dashed in the face. 636. The lingual (hypoglossal) nerve is necessary for the production of articulate speech, regulating and controlling as it does the muscles of the tongue. 637. The trifacial nerve administers the sense of touch to the surface of the tongue, and aids somewhat in the sense of taste. One branch of it is a muscular branch. Another is sent to the mucous surface of the eye, and if it be cut off the eye is destroyed by suppuration. 638. The glosso-pharyngeal is the essential nerve of taste, and is closely connected in function with the trifacial. It seems also to be the nerve through which unpleasant sensa- tions excited in the mouth are conveyed to the medulla ob- longata so as to excite nausea and vomiting. 639. The par vagum sends nervous power to the heart- stomach, lungs, and larynx, as well as conveys to the brain any disagreeable sensations excited in these organs. Conse- quently this is the essential nerve of digestion, respiration, circulation, and opening or closure of the glottis under ordi- nary circumstances. 640. The spinal accessory seems to be the nerve by which the regulation of the muscles essential to the production of voice is effected. 352 HITCHCOCK’S ANATOMY 641. Use of Spinal Nerves. — The use of the Spinal Nerves is to convey impressions made at the surface of the body — including the extremities — to the brain, and to trans- mit impulses to the muscles from the brain. Both of these influences are transmitted by the same nerve or filament, though in opposite directions. From carefully conducted ex- periments it seems quite probable that the “coarse fibers’’ transmit the impulses to the muscles, and are called afferent, while the fine fibers conduct the impressions to the l)rain, and are called efferent. And in the muscular nerves the coarse fiber is proportioned to the fine as 10 : 3.eS, while in the trunk, as it issues from the spinal cord, it is in the ratio of 10 : 11 . IIYGIENTC I TERENCES. 642. TIic Nervous System not easily Diseased. — 1. It is a singular fact that the nervous system, so delicate in its organization and mysterious in many of its functions, is to so small an extent dependent upon any particular rules for the maintenance of its health, the main thing necessary for its welfare being an attendance to the general health of the body. 643. It needs Aetion, — 2. The nervous system, like all other parts of the bod^ requires action for its health. If a person has nothing upon which he can exert his nervous energy, he is liable to disease ; and no class of people are so subject to nervous diseases as the wealthy, who are obliged to make little exertion to procure the necessaries and luxuries of life. Hence we infer that employment of some kind is indis- pensable to the health of the nervous system. 644. Sleep indispensable to its llealtli. — 3. This system C41. What Is tho nso of tlio spinal norvos? What is the ditferenco in function between the coarse and tlio flno fibers? 012. Is tho nervous system easily alb'cted by serious dis- ease ? 648. What is tho necessity of action to tho nervous system ? AND PHYSIOLOGY. S53 requires sound sleep. For this alone can return to the brain its expended energies. It is as necessary to the brain as steam to the locomotive. And no person can enjoy the per- fection of health to old age, who does not gain a due supply of sleep. Hence the very ambitious student, or the man eager to make money, whose time, energies and thoughts are so engrossed that he can not, or will not, find time to sleep, vio- lates one of nature’s principal laws, and sooner or later will receive the penalty. And, according to insane hospital re- ports, one of the principal causes of insanity is put down to a want of sleep. 645. Needs Rest and Recreation. — 4. The mind not only needs sleep, but also recreation or an occasional change of its objects of thought. Long-continued trains of thought are to the brain what working one set of muscles incessantly all day is to them — complete exhaustion. He then that would last the longest, must occasionally turn his thoughts from his or- dinary avocation completely, and so give the brain rest. This applies to every one, whether he is tlm^business man, student, or the hard-working farmer (^;iBfechanic. And every one also needs a vacation, or at least some change of employment, once or twice during the yeam^hen, .for a few weeks or days, he may break up the ordinary»utine of life. 646. Necessity of variousmbi^ts ^for tol'di- vert itself with. — 5. If chan^&^fep-eation be so ip^p^- tant for the health, how necessary tnS^&e ^mind should Wive various objects on which to employ itself from daily duties. How pleasantly, and profitably, for instance, can one pass his leisure hours, if he will but cultivate a taste for music, reading, or some branch of natural history, as for example zoology, botany, mineralogy, or geology! These pursuits not only give healthful physical recreation, but by 644. What is the effect of a want or scarcity of sleep ? What is often a prominent cause of insanity ? 645. What kind of rest does the mind need besides sleep? Do all employments need a vacation ? 646. Is exercise, that is taken simply for exercise, ever the best ? What studies combine profit as well as recreation and exercise ? 354 HITCHCOCK’S ANATOMY tlic attractive and fascinating objects of study which they offer, they divert the mind from the ordinary cares and trou- bles of life, and also exert a healthful moral influence. To literary and professional men, as well as many of business engagements, such a source of recreation and improvement is of very great importance, since often they arc not interested in many of the recreations and pleasures which divert the great mass of society, and also because new thoughts and means of illustration may be gained from them. 647. The Brain must be worked Philosophically, not Spasmodically. — 6. The brain and nervous system will per- form more labor, if w'orked philosophically, than if worked spasmodically. That is, mental and corporeal labor performed regularly and steadily, and only up to the ordinary power of the brain and nerves to sustain, will not wear away the ner- vous system to such an extent as if it be performed by over- working for a few days and then lying idle. 648. Value of "dental Abstraction.— 7. As a general fact the mind acting through the brain can not successfully work in the midst of noise and external attractions. But by practice many can engage in deep study and intense thought, even in the company of those who are talking, laughing, singing, or in the midst of any noise. This is a valuable acquisition and one that should be sought after by every one, since all of us are liable to be thrown into such circumstances, that we must work, think, and transact business in noise and confu- sion. 649. Tliebesl Time for Study. — 8. We see from this sub- ject that the best time for study is in the morning, for then the brain is rested, and can with the greatest vigor and alacrity engage in its efforts. But here the fact presents itself, that the morning is the best time for physical exercise, and to 017. How should tho brain and nervous system be worked ? 64S. What is said of the value of mental abstraction ? 049. What is tho best time for study ? AND PHYSIOLOGY. 355 •which shall we give the preference ? Shall we deprive our bodies of exercise, or shall we give up the best efforts of the brain? Without hesitancy, as a general ru'e^ we should say, attend to the physical exercise first, for if the general health be broken down, the brain will sympathize, and then close mental effort will be at an end. Hence, although morn- ing is the best time for study, yet we must not take the whole of it for that purpose, but must share it with exercise. To a student who is passing through a long course of study, early rising and retiring, and generally exercise in the morning before commencing study, will tend to preserve and invigorate health. Studying late at night and sleeping long in the morning, are injurious to no class of people more than to the hard student. 650. Pernicious Effect of Tobacco on the Brain —9. The effect of tobacco on the brain is thus described, in his medical lectures, by Dr. Solly, an eminent physiologist and practical physician: ‘‘I Avould caution you, as students, from excesses in the use of tobacco and smoking, and I would advise you to disabuse your patients’ minds of the idea that it is harmless. I have had a large experience of brain dis- ease, and am satisfied now that smoking is a most noxious habit. I know of no cause or agent that tends so much to bring on functional disease, and through this in the end to lead to organic diseases of the brain, as excessive use of to- bacco.” 651. Power of the Feelings over the Nervous System. — 10. It is wonderful and interesting to see what is the power exerted by the feelings and emotions upon the nervous sys- tem, and through that upon the whole body. Let the farmer feel that his severe labor is sure to bring him in good crops, and how happily does he persevere in his severe toil month after month. And if the merchant can only know that his But how shall exercise and study both be properly attended to ? What is wSaid of early rising? 650. How does tobacco affect the brain ? 651. What effect have the emotions upon the physical system ? 3oG HITCHCOCK’S ANATOMY gains arc great, how incessantly will he work day and night, and yet consider his no hard life. But if there be no encour- agement, no prospect of reward to the working-man in his employment, what drudgery does it become ! Nay, how posi- tively injurious to health and vigor of body and mind. G52. To the scholar, however, this principle is much more important than to him who labors only with the muscles, since these organs can be worked to a considerable extent with an unwilling mind ; but to Avork a brain already depressed and discouraged is much more difficult, and sure to bring on grave disease. When the spirits are light and the, mind free, the memory can be more readily stored with facts and principles, and the reasoning powers more easily developed. It is hence the duty of teachers to make study as pleasant and attractive as possible ; it becomes those Avho select the location and con- struct the buildings of colleges, academies, and school-houses, to have a reference to taste and comfort in their plans, so that physical inconvenience may not render study irksome, and that the taste of the student may be improved as much as pos- sible by the construction and arrangements of these buildings. 653. Control of the Nervous System by Moral and Religious Feelings. — 11. Finally, of all the sources and promoters of health, correct moral and religious feelings and principles are among the most powerful. The reaction of a guilty conscience upon the body, in obstructing the functions and in bringing on weakness and premature decay, is well known. Equally powerful in promoting health and longevity is an approving conscience. A cheerful acquiescence in the divine will has often done more to restore the invalid and maintain good health against disease, than all medical reme- dies ; while pure and ennobling sentiments and religious hopes have sometimes been more efficacious to prolong life on earth t’lan Jill otlier liygicnic prescriptions. 052. Wliiit cfViict lias plonsiiraMo foolinfjs on tho progress of the scholar? 053. State the valiin of an upproviuj^ coiibciciice upon all claases of society, as it simply respects phybical hcalLli. AND PHYSIOLOGY. 357 COMPARATIVE NEUROLOGY. 654. Amono; all the higher mammals we are able to trace nearly all the different parts of the nervous system as they are exhibited and arranged in man, though many of them are considerably modified. 655. Weight of Brains. — The relative weight of the brain is greater in the smaller animals. Thus, in the mouse it is said to be the weight of the body. In the elephant the weight of the brain is Fig. 329. Brain of Squirrel laid open. B, Cere- brum. D, Cerebellum. C, Optic Lobes. that,, Thalamus Opticus, c, s, Corpus Striatum. Fig. 330. Upper and Under Surface of Brain of Rabbit. A, B, D, as before. oZ, Olfactive Lobes, op, Optic Nerve, mo. Motor Oculi. cm, Corpora Mamillafia. c, c. Crus Cerebri, pv^ PonsVarolii, per, Patheticus. tri, Trifacial, ab, Abducens. fac^ Facial. Audi- tory. Vagus, s. Spinal Accessory. App., Hypoglossal. 655. What is said of the size of brains ? 858 HITCHCOCK’S ANATOMY the weight of the body; in the ox, yljjth; in the fox, v j-th; while in man it is the weight of the body. 656. Proportion of the AViilth of Brain and Spinal Cord in Man and other Mammalia. — This, as well as the comparison of cerebral mass and cerebral nerves, between man and other animals, is interesting. The breadth of the spinal marrow is, to that of the breadth of the brain, in man, as 1:7; in the dog, as 1 : 2. 657. Cerebral Nerves. — “The cerebral nerves correspond to those of man. The first pair, however, forms in some de- gree an exception, for though not absent in all the whale family, it is wanting in the dolphins. In most mammals the olfactory nerves are thick and have a cavity in them. The fifth pair of nerves is, in many mammals, of peculiar strength and thickness when compared with that pair in man.^’ 658. Sympathetic System. — “The nervous system of organic life— the great sympathetic — is formed, as far as in- vestigations indicate, essentially as in man.’' It is situated mostly in the cavities of the thorax and abdomen, and follows the course of the blood vessels. 659. Tentorium. — The tentorium cerebelli, which in man is a simple tough membrane that separates the cerebrum from the cerebellum, is very delicate in some animals, as the horse and dolphin ; while in the cat it is supported by a bony plate springing from the skull, and is a very firm membrane. Its use to protect the brain in those animals whose movements are at times violent and sudden, and especially those that leap great distances. 660. Spinal Nerves. — The Spinal nerves also, in general appearance, are like those in man. The number of pairs varies in diffiTcnt species, as might be inferred from the dif- fering number of their vertebrae. C50. State tlio i)roportion of llio width of the brain and spinal cord. C57. What is said of the c< 5 rcbral nerves of animals? 058. Wliat is said of the sympathetic system? 659. What is said of the tentorium ? 060. What of the spinal nerves of animals f AND PHYSIOLOGY. 359 661. Actual Proportion between Cerebrum and Cere- bellum. — According to Cuvier, the proportion of the cere- bellum to the cerebrum, by weight, in the baboon, is as 1:7; in the dog, 1:8; in the sheep, 1:5; and in the horse, 1:7. 662. Spinal Cord. — The essential difference between the spinal cord in man and the lower mammalia, is its greater length, and a narrow canal which runs longitudinally through the middle of it. 663. Nervous System of Birds.— The brain of birds is characterized by the smallness of the hemispheres, though more fully developed than in reptiles and fishes. In the sparrow the weight of the brain to the whole body is as 1:25; in the goose, 1 : 300 ; and in the cassowary, 1:1000. It is destitute of convolutions, or in other words is perfectly smooth on its surface, and has large cavities or ventricles con- tained in it : and, as in mam- mals, the mass of the brain Optic GangUa. D, Cerebellum, fir, Pineal is greater than that of the spinal cord. The pairs of the cerebral nerves are the same as in mammals ; also the principal divisions are the same. The cerebellum, as in man, exhibits the arbor vitae when cut through vertically. 664. Nervous System of Reptiles. — The brain of rep- Fm. 331. 661. What is the proportion between the weight of the cerebrum and cerebellum in some of the lower animals ? 662. What is the essential difference betwee"' the spinal cord of man and that of most quadrupeds ? 663. How is the brain of birds characterized ? Give some of the proportional weights of it compared with that of the whole body V IG 360 HITCHCOCK’S ANATOMY tiles constitutes but a very small part of the body. In the frog the proportion to the Avhole weight of the body is as 1:172; in the Coluber matrix (snake), 1 : 792 ; in a turtle, 1 : 5688. The hemi- spheres are smooth and hollow internally. The optic lobes are large in proportion to the size of the eyes, and are hoi-, low internally. The cerebel- lum of frogs is merely a thin plate of nervous matter. 665. Nervous System of Fishes. — We find the lowest Brain of Turtle. A, Olfactive Ganglia. , , B, Cerebrum. C, Optic Ganglia. D, Cere- development Ot the nerVOUS system among vertebrates in the fishes. The brain here does not fill the whole cranial cavity, so that between the brain and dura mater there is found a quantity of loose cellular tissue, with which is inter- spersed a fluid oil. The brain in weight does not equal that of the spinal cord, nor is it but a little broader than the cord. Its weight in proportion to that of the body is about 75^0 oth part. It is composed of eight lobes, partly in pairs, and partly unpaired behind one another, which seem to correspond to the cerebellum (divided), corpora quadrigemina, thalami optici, and medulla oblongata. 666 . Elcclrical Organs in Fishes. — There are at least seven species of fish that possess the power of giving electric discharges. The organs which accomplish this in the Torpedo are two large crescent-like bodies (see Fig. 334), which are 00-1, Wluit snifl of tlio brnin of roi)tilfis? State its comparative size with that of the wliole Ixxly. 005. State some of the peculiarities of the brain in fishes. What is its relative*, wciirht? 000. What is said of the electrical orgaus of some fishes? Give tho anatomy of these organs. AND PHYSIOLOGY. Pia. 333. 301 Brains of Fishes. A, Olfactive Lobes or Ganglia. B, Cerebral Hemispheres. C Op- tic Lobes. D, Cerebellum, ol. Olfactory Nerve, op, Optic Nerve, pa, Patheticifs «<,, Motor Ocu i. aj Abducens. Trifacial. /«, F.aclal. AadL’y. A: gus. tt, Tubercles or Ganglia of the Trifacial. U, Tubercles of the Va<^us. made up of a large number of short, six-sided prisms, and are abundantly supplied with nerves. And as these organs are made up of prisms, which stand end upon end, and not side by side only, as they appear in the cut, the idea seems 362 HITCHCOCK’S ANATOMY Tig. 334. Fig. 335. Electrical Apparatus of Torpedo. 5, Nervous System of an Articulate. BranchifE. c, Brain, e, Electric Organ. ( 7 , Cartilage of Cranium, me, Spinal Cord, w, Nerves to the Pectoral Fins, nl^ Lat- eral Nerves to the Body, np^ Large Nerves (Pncumogastric) to the Electric Organ, o, Eye. plausible that they may he regarded as Voltaic piles, or a reservoir of electric power which the fish can discharge at will. And it is necessary for the generation of this electrical discharge that the integrity of the nervous system be main- tained. G67. Nervous System in Articulata. — In the Crusta- ceans the nervous system consists of ganglia and cords. The central ganglion may be regarded as a brain, which sends off nerves of vision, audition, feeling, and smelling. A splanch- nic or sympathetic nerve is also found, as in the Arachnoidea and Annelida. The two latter classes have ganglia, which CC7. State tlio general plan of the nervous system in articulates. AND PHYSIOLOGY. 363 Fig. 336. may be called a brain. In Insects the central parts of the nervous system con- sist of a brain and a ven- tral cord/^ as is shown on Fig. 336. In some of the lower tribes of Articulates, as the Helminthes and Rota- toria, the nervous system is feebly and indistinctly de- veloped. 668. Reflex Actions in Ar* Nervous System of a Beetle. t i c u 1 a t e s . — This sub-king- dom is remarkable for its reflex actions. Thus if the head of a centipede be cut off while it is in motion, the body will con- tinue to move by the action of its legs ; and the same will take place, if the body is divided into several segments. The explanation is as follows. ^^The body is moved forward by the regular and successive action of its legs, as in the natural state : but its movements are always forwards, never back- wards, and are only directed to one side, when the forward movement is checked by an interposed obstacle. Hence, al- though they might seem to indicate consciousness and a guid- ing will, they do not so in reality : for they are carried on as it were mechanically, and show no direction or object, no avoidance of danger. If the body be opposed in its progress by an object of not more than half its height, it mounts over it, and moves directly onwards, as in its natural state : but if the obstacle be equal to its own height, its progress is ar- rested, and the cut extremity of the body remains forced up against the opposing substance, the legs still continuing to moveP What is the name of the principal ganglia? 668. What is said of the reflex actions of articulate animals ? What are these reflex actions sometimes mistaken for ? Give the example. 364 HITCHCOCK’S ANATOMY 669. Nervous System of Molluscs— Cephalic Gang- lia. — Pedal Ganglia. — Parieto- Splanchnic Ganglia. — In most of the Molluscs the nervous system is well de- Fig. 337. Nervous System of Argonauta Argo. A, As seen in front. B, As viewed in profile, fihowing tho relations of the Nervous Centers to the Buccal Mass, a, The Esophagus b, and tho Eye c. a, Cephalic Ganglion, Buccal Ganglion, c, Sub-Esophageal Gang- lion. escribo the sclerotic coat. G8i. What is the cornea? To what may it be com- pared in the watch ? AND PHYSIOLOGY 371 682. Choroid Coat —Iris. — Ciliary Processes.— The middle coat of the eye is made up of three portions, the Choroid membrane, the Iris, and the Ciliary pro- cesses. The first, Choroid, is named from the fact that it is entirely made up of blood- vessels, of a chocolate-brown color on the outside, and a deep black on the inside. It covers the posterior four fifths of the eye, and corresponds to the sclerotic coat outside of it. The Iris, so called from the diversity of color which Plan of the Structures in the Fore Part of the Eye, seen in Section. 1, Conjunctiva. 2, Sclerotica. 3, Cornea. 4, Choroid. 5, Annulus Albidus ; before this is is seen the Canal of Fontana. 6, Ciliary Processes. 7, Iris. 8, Retina. 9, Hyaloid Membrane. 10, Canal of Petit (made too large). 11, Membrane of the Aqueous Humor (too thick.) c/. Aqueous Humor; Anterior Chamber, and (a,) Posterior Chamber. &, Crystalline Lens, c, Vitreous Humor. Fia. 341. 6 Choroid Coat of the Eye. 1, Curved lines marking the arrangement of Venae Vorti- cosae. 2, 2, Ciliary Nerves. 3, A long Ciliary Artery and Nerve. 4, Ciliary Ligament. 5, Iris. 6, Pupil. 632. Of what three portions is the choroid coat composed ? Give their names. De- scribe the Iris. 872 HITCHCOCK’S ANATOMY it presents in diflferent persons — and it is the color of this which we mean when we speak of the color of the eye — cor- responds in position to the cornea lying immediately under it. FiG. 342. Fig. 343. External View of the Iris. Anterior Segment of a Transverse Section of the Globe of the Eye seen from within. 1, Divided edge of the three Tunics ; Sclerotic, Choroid (the dark layer), and Ketina. 2, Pupil. 3, Iris, the surface presented to view in this section being the Uvea. 4, Ciliary Processes. 5, Scalloped Anterior Border of the Ketina, It is circular in form, containing a few muscular fibers, with a circular opening through its center, from one third to one twentieth of an inch in diameter, which is known as the pupil. The Ciliary processes are minute triangular folds of the Cho- roid coat, which lie upon the interior surface of the iris, with their bases directed toward the pupil. They are about sixty in number, and are divided into large and small, the latter being placed between the former. The Pigmentum Nigrum, or black paint, is an extremely tenuous membrane, which lines the inside of the choroid coat. It is of a jet black color, and is easily destroyed merely by allowing a stream of water to fall upon it. 683. Retina. — The inner membrane of the eye is the Re- tina, which is merely an expansion of the optic nerve, upon Wluit Is the diiiinctcr of tlio iris? What arc tlie ciliary processes? How many are tlioro? What is the pigmentum nigrum ? 683. Describe the retina. , AND PIIYvSIOLOOY 373 the inner side of a hollow sphere, formed hy the membranes already mentioned. 684. Microscopic Structure of these Membranes. — The structure of these membranes, as revealed by the micro- scope, is very complex. The Cornea is made up of four sim- ple membranes, the Choroid of three, and the Retina of four. Tig. 344. Vertical Section of tlie Human Retina and Hyaloid Membrane, h, Hyaloid Membrane. 4', Nuclei on its inner surface, c, Layer of Transparent Cells, connecting the Hyaloid and Retina, c', Separate Cell enlarged by imbibition of water, Gray Nervous Layer, with its Capillaries. 1, Its Fibrous Lamina. 2, Its Vesicular Lamina. 1', Shred of Fi- brous lamina detached. 2', Vesicle and Nucleus detached, g. Granular Layer. 3, Light Lamina frequently seen. g\ Detached Nucleated Particle of the Granular Layer, w, Ja- cob’s Membrane, m'. Appearance of its Particles, when detached, m". Its Outer Sur- face. — Magnified 320 diameters. The Sclerotic is for the most part made up of white fibrous tissue, and a large portion of the Choroid coat is composed of blood-vessels, although the inner membrane — the Pigmentum Nigrum or black paint — consists of minute six-sided cells re- sembling a tesselated pavement. The Retina is for the most part made up of the different forms of nervous tissue and its membranes. 634. Give the microscopic structure of the cornea. Of the choroid, the pigment, and the retina. 74 HITCHCOCK’S ANATOI^rY 685. Humors of the Eye; Aqueous— Of the three Hu- mors or liquid substances composing the eye, the Aqueous or Avatery is situated in the anterior portion of this organ behind the cornea, and in front of the crystalline humor soon to Ix) described. It is a liquid like water, with an alkaline taste, and only a few drops in quantity. The Iris is placed directly in the middle of this fluid. 686. The Lens. — The Crystalline Lens or Humor (so called because it refracts light and is transparent like a crys- tal) is a double convex lens, the posterior convexity being Fig. 345. Fig. 346. Front View of the Crystalline Lens. Side View of the Lens. 1, Anterior Face. 2, Posterior Face. 3, Circumference. greater than the anterior, and is located directly behind the pupil, so that all the light Avhich enters the eye, must pass through this and be refracted. This lens is made up of con- centric layers like an onion, and also of three triangular seg- ments, with their sharp edges directed towards the center, both of which structures, by boiling the lens in water for a short time, can be readily seen. Fig. 347 represents the difierence in diameters of the lens at difierent periods of life, a, rep- resents it at birth, 6, at six years of age, c, its appearance in an adult, and rf, after it has been Fig. 347. 0 Crystalline Lens, a, At birth. 6, At six years old. c, Adult, rf, Altered by alcohol. C85. How many humors are there in the eye? Describe the aqueous. ^6. What is the crystalline humor ? What kind of a Ions is it? Of how many segments is it made up f AND PHYSIOLOGY. 375 hardened and partially divided into segments by an immersion in alcohol. 687. Vitreous. — The Vitreous Humor (from its resem- blance to glass) is of the form of a sphere, with the anterior portion removed, and constitutes seven eighths of the globe of the eye. It is a transparent fluid enclosed in a transparent membrane, and through its central portion from the entrance of the optic nerve, there passes a small artery to the lens, which supplies it with blood. 688. Lachrymal Gland. — Nasal Duel. — At the outer angle of each eye is found a gland called the Lachrymal gland, nearly three fourths of an inch in length, and of a flattened oval Fig. 348. Posterior View of the Eyelids and Lachrymal Gland. 1, 1, Orbicularis Palbebrarum Muscle. 2, Borders of the Lids. 3, Lachrymal Gland. 4, Its Ducts opening in the Up- per Lid. 6, Conjunctiva covering the Lids. 6, Puncta Lachrymalia. 7, Lachrymal Ca- runcle as seen from behind. shape. (Fig. 348.) Passing from this gland to the eye, are from eight to twelve small ducts, which open upon the under side of the lid near its edge, about one twentieth of an inch apart, which carry the tears to the eye. By continual winking this 687. From what docs the vitreous humor get its name? Describe it. 688. Where aro the lachrymal glands situated? What is their size ? How many ducts have they ? What do they secrete ? Of what use Is winking? 37G HITCHCOCK’S anatomy Fig. 349. Lachrymal Canals. 1, Puncta Lachry- malia. 2, Cul-de-Sac at the Orbital End of the Canal. 3, Course of each Canal to the Saccus Lacryrnalis. 4, 5, Saccus La- crymalis. G, Lower Part of the Ductus ad Nasum. fluid is uniformly distributcMl over the Avhole hall of the eye, and the excess is carried away from the eye liy the two lachrymal canals, which commence at the two little projections near the inner angle of each lid of the eye, appearing like minute black specks. Both of these very soon unite into a larger tube called the nasal duct, (Fig. 349.) which descends inwardly and empties itself upon the nostrils. G89. Eyebrows . — The Eyebrows are projecting arches of fat and skin, cov- ered with short and thick Fig. 350. hairs which encircle the upper portion of the eye. They are provided with muscles, so that they can be made to shade the eye more or less perfectly, as ne- cessity may require. 690. Eyelids.— The Eyelids are movable membranous and mus- cular coverings which are placed directly up- on the eyeball, and are designed for protective organs against mechanical violence and too powerful light. Their free edges are called T|irsal Carti- Front View of the Left Eye — moderately opened. 1, Supercilia. 2, Cilia of each Eyelid. 3, Inferior Palpebra. 4, Internal Canthus. 5, External Can- thus. 6, Caruncula lacryrnalis. 7, Plica Semilu- naris. 8, Eyeball. 9, Pupil. Where are t.lio lachrymal canals and what do they carry? What is the nasal duct? CS9. Describe the eyebrows. 090. What are the eyelids? What arc their edges made up of? What glands directly in them ? AND PHYSIOLOGY, 377 lages, directly in the substance of which is placed a large quantity of minute glands, called Meibomian Glands. Fig. 351. Fig. 352. Meibomian Glands seen from the Inner or Ocu- lar Surface of the Eyelids, with the Lachrymal Gland— of the Eight Side, a, Palpebral Conjunc- tiva. 1, Lachrymal Gland. 2, Openings of Lachry- mal Ducts. 3, Lachrymal Puncta. 6, Meibomian Glands. 691. Muscles of the Eye. — The Ball of the eye is moved by six distinct muscles, four straight and two oblique muscles, as is shown in the cut. Their names are Rectus Superior and Inferior, nal, and Superior and Inferior Oblique. Meibomian Gland highly magnified. External and Inter- Muscles of the Eyeball. 1, A small FiG. 353. Fragment of the Sphenoid Bone around entrance of Optic Nerve into Orbit. 2, Optic Nerve. 3, Globe of Eye. 4, Levator Palpebrje Muscle. 5, Superior Oblique Muscle. 6, Its Cartilaginous Pulley. 7, Its reflected Tendon. 8, Inferior Oblique Muscle; the small square knob at its com- mencement is a piece of its bony origin broken off. 9, Superior Rec- tus. 10, Internal Rectus almost con- cealed by Optic Nerve. 11, Part of External Rectus, showing its two heads of origin. 12, Extremity of External Rectus, at its Insertion; the intermediate portion of muscle having been removed. 13, Inferior Rectus. 14, Tunica Albuginea formed by expansion of tendons of four recti. 691. How many muscles for moving the eyeball ? Give their names. 378 HITCHCOCK’S ANATOMY FUNCTIONS OF THE EYE. 692. The primary and obvious use of the eye is to receive the form and color of different objects, and to transmit them to the brain. 693. Use of llie Coats — Sclerotica — Cornea — Choroid — Black Paint — Iris — Ciliary Processes — The Retina. — The use of the firm and hard sclerotic coat is to give a firm attach- ment to the muscles which move the eye, and also secure pro- tection to the delicate parts within. The cornea is tough but transparent, so that the anterior portion of the eye may be firm and at the same time admit the rays of light. The cho- roid coat furnishes the blood to the eye, it being for the most part entirely made up of blood-vessels. It also secretes the black paint (Fig. 288), which is of great service in absorb- ing the superfluous or wandering rays of light which otherwise would obscure the image on the retina. A similar provision is made by painting black the tube of the telescope and mi- croscope. The iris regulates the amount of light entering the ball, by its contraction and expansion. This function is per- formed by the radiated and circular muscular fibers, the latter of which contract by the stimulus of strong light; but if the light be feeble, the radiated contract, and thus enlarge the pupil. The retina, with the vitreous humor in front and the black paint directly behind it, receives the image of the object before the eye. It bears the same relation to the other parts of the eye as the silvered or glass plate does in the camera of the photographist. This impres- sion is carried to the brain by means of the optic nerve. 694. Use of the Humors — Aqueous— The Lens— Vitreous^ — Of the three humors or media o^ the eye, the aqueous is the least important, since if by accident or operation it is re- 092. state the use of the eye. C93. Give the use of the sclerotic coat. Of the cornea. What does the cliorold furnish to the eye? Of wliat service is the black paint? What docs the Iris do? What is the function of tlie ciliary processes? What is the use of the retina? C94. Which Is the least Important of the humors ? AND PPIYSIOLOGY. moved, nature will soon replace it ; but this is true of no other medium. The aqueous humor, however, is of great use to keep the front parts of the eye in a soft and elastic condi- tion, and also to furnish a medium in which the iris may readily be contracted and relaxed. It also aids in properly refracting the rays of light, so that the most perfect image may be formed on the retina. The use of the crystalline lens is also to refract the rays of light, so that an image of suffi- ciently small size may be formed on the retina. Otherwise, when we look at any object larger than the diameter of the pupil, we should be unable to see it, only by successively looking at minute portions of it. The vitreous humor assists in the same refraction of the rays, and incidentally subserves the purpose of fixing at a proper distance the lens, so that the image may be formed exactly at that point on the retina called the focus, where it will be the most distinct. 695. Need of Three Media.— But what is the necessity for three media of refraction, and why will not the crystalline lens answer the whole purpose ? This is owing to some of the properties of light. Light is composed of seven rays or colors, some of which are more easily refracted than others ; that is, some rays are bent farther from a perpendicular to the sur- face than others. Hence, upon the edges of an image formed by a single lens, every part of which is of the same density, we should see several of the prismatic colors, which would give an indistinct image. In the telescope and microscope this difficulty is remedied by forming a lens of crown and flint glass, one of which has a stronger dispersive or refractive power than the other. In the eye the same error is obviated by means of the crystalline lens, which has a greater refrac- tive power than the vitreous humor, and consequently, when the ray is too much refracted by the crystalline lens, a corn- state the use of the aqueous. The use of the lens. What does the vitreous humor aid in? 695. What is the need of three humors ? IIow many distinct colors does light con- sist of ? What similar purpose do lenses of different densities answer in telescopes? Which of the three humors has the greatest refractive power ? 880 HITCHCOCK’S ANATOMY pcnsation is effected by the vitreous humor, which refracts less than the lens. 696. The Secretion of the Lachrymal Clands.— The lach- rymal gland is designed to secrete a saltish fluid known as tho Tears. This is of great service in lubricating and keeping moist the surface of the eyeball, so that it may move readily in its socket, and also to keep the cornea from becoming hard and dim. The tears also moisten the back part of the nostrils, and are ultimately poured into the pharynx. The amount of tears which is daily secreted is estimated at four ounces, and it is greatly increased by strong emotions, whether pleas- ant or sorrowful, as it is well known that a person is apt to cry when very sad or very happy. 697. Service of the Eyelids — Necessity of Constantly Winking — Eyelashes. — The eyelids are of service to keep the light from the eyes when it is too intense, or when it is necessary to exclude it entirely, as during sleep. Another valuable service which they perform is to spread the tears constantly and uniformly over the eyeball. This is the rea- son why we are constantly but unconsciously winking during every few seconds of our waking hours. The eyelashes which line the edges of the lids, prevent the perspiration which is secreted on the lids from entering the eye, and thus irritating it, since by the law of capillary attraction the tears will run towards the free extremity of the hair, where they will accu- mulate to such a size that they drop off. The eyelashes also prevent, in some degree, dust from entering the eye. 698. Use of the Eyebrows. — The eyebrows perform a similar office to the eyelids, though not so important. The hairs which cover them, like the lashes, convey away the per- spiration from the forehead, and allow it to fall in front of the eye, and not directly upon the ball ; while, by means of the G9G. Wliiit is tlio secretion of tho lachrymal gland? What is the use of the tears? What quantity of tears are secreted daily? G97. Of what service are the eyelids? Why clo wo constantly wink? Of what service are tho eyelashes? 698. What service do the eyebrows perform? AND PHYSIOLOGY. 881 muscles attached to the integuments, whenever it is desired they bring the brows in front of and above the eye in such a manner as to afford it a very considerable protection from ex- cessive light. 699. Short and long-Siglitedncss.— The phenomena of short and long-sightedness are worthy of a passing notice. Short-sightedness results where the lens of the eye has too much convexity, which causes the image to be formed in front of the retina. In such persons the eye generally has greater prominence than in others. But persons thus affected will probably in later years have better eye-sight than if short- sightedness had not existed. A too much flattened state of the lens occurs in those who are long-sighted. This is gener- ally the case with those somewhat advanced in life. In this case the distinct image will be formed behind the retina, and it requires a convex lens, in the form of spectacles, to correct the error. 700. Other Interesting Phenomena of Vision.— A few other phenomena connected with the function of vision de- serve attention. One is the fact, that although we have two eyes and two distinct images are transmitted to the brain, yet but one object is seen. And if we look at an object with only one eye, we see the image nearly as distinct as with both eyes. Another is, that although the image on the retina is inverted, yet to the mind it appears in its true position. For, since the rays of light pass through the lens in nearly straight lines, the ray coming, for instance, from the top of a tree, will fall upon the lowest part of the retina, while the ray coming from the bottom will strike the upper part, and hence the image will be inverted, although to the mind^s eye’’ it will be erect. Another fact is equally wonderful. We are able to see with distinctness an object only a few inches from our 699. Whivt is the cause of short-sightedness? What is the reason of long-sightedness ? What kind a lens is required for long-sighted people, and why ? 700. What curious facts coniiectetl with the physiology of vision ? 382 HITCHCOCK’S ANATOMY eyes, and almost instantly, by turning them to a mountain top several miles distant, we can see an object there with per- fect cleaarness. No optical instrument can be made which will so quickly do this, for it is necessary to make a new ad- justment of the lenses to adapt it to different distances, but the eye is at once ready. It is supposed that this adjustment is effected by a shortening or lengthening of the diameter of the crystalline lens, or by drawing the lens towards the pos- terior part of the eye, by means of a few muscular fibers called the ciliary muscle, running from the bones of the nose to the cornea, which by their contraction would force the aqueous humor upon the crystalline lens in such a manner as to flatten it, and by a relaxation of the same fibers a dilata- tion in an antero-posterior direction is effected, and that in- stantly. 701. Experiment for Seeing the Arteries of tne^s own Eye. — The image of the arteries of one’s own eye can be readily seen in the following manner. In a dark room place the left hand over the left eye, and in the right hand hold a lighted candle by the right side of the head, and very near to it. Then with the right eye open, looking towards the darkened wall, move the candle up and down rather quickly, and in a few seconds dark branches will appear at a short dis- tance from the eye, looking like the limbs of a tree, which are images of the arteries distributed on the retina. 702. limits of Vision. — What is the size of minute ob- jects that can be seen by the naked eye ? Ehrenberg, fn eminent microscopist, says that nearly all eyes have eqrjal power to discern minute objects, whether long or short-sighced. The smallest square magnitude visible to the naked (jye, cither of white particles on a dark ground, or the reverse, is about the ^ J^^th of an inch. Brilliant particles which pow- llfiw is Iho tolcscopic and the microscopic power of the eye explained? Ilowcan we see the iinaf?o of llio arteries of our own eyes? 702. What is the sinallesc square sur- face that can bo seen with the naked eye ? AND PHTSIOLOGT. 883 erfully reflect light may be distinctly seen when not half the size of the foregoing. Thus gold dust the ttV part of an inch in diameter is visible in common daylight. Lines may be more readily seen than points. Opaque threads 4 Vo o th of an inch in diameter can be seen when held towards the light. Attention also greatly helps to discern minute objects, or at least to retain them in sight when once pointed out. Thus we are often able to see a faint star in the sky or a ship in the horizon after they have been pointed out to us, although they were not seen before. “ I myself,’^ says Ehrenberg, can not see stV^ th of an inch, black or white, at twelve inches distance ; but having found it at from four to five inches distance, I can remove it to twelve inches and still see the object plainly.’’ 703. Color Blindness.— Many people are afflicted with an inability to distinguish certain colors of the solar spectrum. This is cadled Color Blindness, or Daltonism. 704. Formerly it was supposed that this afiection was very rare, bu^c later researches show it to be quite common. Ac- cording to experiments made by Dr. Wilson upon 1154 per- sons in* Edinburgh in 1852 and 1853, it was found that — 1 in 55 confonnds red with brown. 1 in 60 confounds brown with green. 1 in 43 confounds blue with green. ujlence one in every 17.9 persons is color blind. /THE SENSE OF VISION IN ANIMALS. 705. Tapctiim— Pupil— Nictitating Membrane— llarde- riaii Gland. — The general anatomy of the eye of mammals difie rs but slightly from that of man. Between the sclerotic and c’.horoid in some animals is found another membrane of a How is .’t with brilliant particles? How is the ready vision of lines compared with points? How small a thread can be seen by the naked eye? What elfeet has the fa- miliarity wiU’i an object ? 703. What is color blindness ? How often is this peculiarity found? What colors are most commonly confounded ? 17 384 HITCHCOCK’S ANATOMY metallic brilliancy, with different shade of color, known as the Tapetum. In horses and cows it has a variegated luster of green and blue, while in the tiger, cat, and whale it is of a silvery brightness. The shape of the pupil in the wolf and dog, which need vision in all directions, is circular ; while the fox and cat, which need a vertical range more than any other, have a perpendicular slit only. In cattle and the more timid grazing animals which obtain their food from the ground, and need to look behind with ease when pursued, the pupil is a horizontal ellipse. Nearly all mammals except man and the apes, have a third lid, which is a transpareit membrane that is frequently slid over the ball by a pecukar muscular apparatus. This is called the haw’’ or Nictitating Mem- brane, and, especially in birds, serves the purpose of remov- ing impurities from the eye, and also of spreading the secre- tions over it, in order to keep it moist and transparent. In addition to the lachrymal gland, in all animals which have the third lid there is another gland called the Harderian Gland, which prepares another secretion similar to and for nearly the same purpose as the lachrymal. 706. Eyes of Birds — Pecten Marsupium. — All birds, without exception, are provided with perfect and well deveb oped eyes. They are always large, and largest in birds of prey. They are but slightly movable themselves, but this want of motion is compensated by the great mobility ol. the head. The sclerotic coat is strengthened in front by a series of bony plates, fourteen or fifteen in number, interposed be- tween its fibrous layers, a great use of w^hich is to give at- tachment to the special muscular apparatus for adapting the eye to see objects at different distances. The anterior chan^iber is proportionally larger than in any other animals, so that the iris is far back from the cornea. The iris has different shades of color, commonly yellow or brownish. The yellow color of 705. What is tin; tapotuiii ? WHiat is its color? W^liat is the shape of the pupil in the ■wolf, do}', and ill (Jiittle ? What is the Nictitatin, Transparent Pyramids surrounded wi*ch Pig* iiuiiit. c, Fibers of ihe (>[)tic Nerve. (1^ Trunk of the Optic Nerve. -? ; W'hat are the pigmentary spots? 709. What are compound eyes? Whats'.ab-kiiigdoia do they characterize? How does the eye ttpi»ear on many insects? AND PHYSIOLOGY. 87 Fig. 356. magnifying glass, is found to be made up of a vast number of facets, which are generally hexagonal. In the common house fly there are 4,000 in each eye, in the dragon fly 24,000, and in one species of the beetle 25,000. Each one of these facets is found to be the end of a little eye, the frus- trum of a slender pyramid standing by its apex on a bulbous expansion of the optic nerve. The interior of this pyramid is filled with a trans- parent substance which represents the vitreous humor, while between the frustra is found the black pigment. Both surfaces of these facets FossU TriboUte constructed on the same are found to be convex, plan- and it has been calculated that the focus of these lenses would be at a point just at the extremity of the pyramid where it joins the optic nerve. And since the rays of light entering onp of these facets can not enter the other on account of the black pigment intervening between them, the range of vision to the insect would necessarily be very limited were it not for their enormous multiplication, by which in reality a separate eye is provided for every point to be viewed, thus giving to fhe insect as perfect an apparatus of vision as we have, al- ‘fiough immovably fixed on the body. 710. S t e m m a t a . — Besides the composite eyes, insects usu- ally have a small number of simple eyes situated upon the top * f the head, called Stemmata. If they are covered with paint, t he movements of the insect are constantly upward. 711. Other Articulates. — A few insects that live in dark places have no eyes. Some Crustaceans have compound eyes withiut facets, and others with them. Some Annelids have eyes, others none. The Rotatoria have vision, but the Ilel- What nuLiber of facets are there in the house fly and in the dragon fly? Give the an- atomy of each facet or pyramid. 710. What other organs of vision besides compound eyes do insects have ? If the stemmata are removed what is the result ? Til. What of the eyes of art>,ulates ? 388 ir I T C II C O € K ’ S ANATOMY minths are without eyes. Among Araclinida (spiders) the eyes bear a near relation to the vertebrate type of eyes. Their number is much less than among the other articulata, seldom more than eight, and are to be compared more with stemmata than with compound eyes. Sometimes these are collected into one mass upon the second segment of the body, and some- times they are arranged symmetrically upon the median line. 712. Eyes of Molluscs, — The organs of vision in the Acephala are numerous, rising as high as forty in the genus Pinna, where they are placed in the mantle. The Cephalo- phora have generally two eyes. In the Cephalopoda the eyes are disproportionately large, and possess nearly all the parts found in the eyes of vertebrates. \ 713. Eyes of Radiates. — The Polypi show a sensibility to light, but no eyes have been discovered in them. The Acalephse seem to have the sense of vision, and Agassiz seems to have ascertained the presence of an organ for this purpose in some of them. It is more doubtful in respect to the Echi- noderms. WTiat eyes have spiders? 712. What are the eyes of molluscs? 713. What is said the organs of vision among radiates ? i i ,1 AND PHYSIOLOGY 389 THE SENSE OF HEARING. DEFINITIONS AND DESCRIPTIONS. 714. Parts of the Ear, — The organ of hearing is made up of three distinct portions : the Pinna or external ear, the Tympanum or middle ear, and the Labyrinth or internal ear. 715. The Pinna, — The Pinna, commonly known as the Ear, is a cartilaginous plate with numerous irregularities upon its surface, and having upon it a few muscular fibers, which 357. Fig. 358. A View of the Left Ear in its Natural state. 1, 2, The origin and termination of the Helix. 3, The Anti-Helix. 4, The Anti-Tragus. 5, The Tragus. 6, The Lo- bus of the External Ear. 7, Points to the Scapha, and is on the front and top of the Pinna. 8, The Concha. 9, The Meatus Auditorius Externus. An Anterior View of the External Ear, as well as of the Meatus Auditorius, Laby- rinth, etc. 1, The Opening into the Ear at the bottom of the Concha, 2, The Mea- tus Auditorius Externus or Cartilagin- ous Canal, 3, The Mcrnbrana Tympani stretched upon its King, 4, The Malleus. 5, The Stapes, 6, The Labyrinth. 714. What are the three parts of the organ of hearing? 715. Describe the pinna. 390 IIITCnCOCK’S ANATOMY are in fact rudimentary muscles, 5 in number. In some men they have been so fully developed that the cars could bo moved by their action, while among quadrupeds there arc but few that do not possess this power. The Pinna somewhat resembles a funnel, forming at its base an irregular tube called the Auditory Canal, about half an inch in diameter and an inch in length, which terminates with the Tympanum. A few stiff hairs arc found upon the sides of this canal, and in the lining membrane some glands, which secrete the wax of the car. 716. The Tympanum —Membrana Tympani,— little Bones of the Ear. — The Tympanum is an irregular cav- ity located in the petrous portion of the Temporal bone, measuring rather more than one half inch in its longest diameter. At the point where the Auditory Canal joins the Tympanum, the Membrana Tympani is found, wdiich is simply an impervious mem- brane stretched between the tw^o cavities, dip- ping inwards at an an- gle of forty-five degrees. To this membrane are attached three muscles for the purpose of ren- dering this membrane lax or tense, as may be View of tho Cavity of the Tympanum, the Ossicula Auditus, and their Muscles, magni- fied. «, rt, Cavity of tho Tympanum. Membrana Tympani, or rather the osseous circle to which it is attached, c, Handle of the Malleus, resting on the middle of the Membrana Tymi)ani. inna? How ai>illu). Fig. 366. Papilla) of the Palm of the Hand. AND PHYSIOLOGY. 401 skin, in which are found the loop of a nerve, and a blood- vessel with some cellular tissue. The main use of them seems to be to place the nerve in such a position, that it will be most easily impressed with whatever external substances it may be brought into contact. FUNCTIONS. 736. The Superficial Parts of the Body most abundantly Supplied with Nerves. — The parts of the body lying deep beneath the skin, are but sparingly supplied with nerves of sensation, which is a great comfort to those un- fortunate persons who are subjected to surgical operations, since the most painful part is in cutting through the skin, which is the quickest part of the operation. This, however, is the case only when the deep parts are in health (including the bones) ; for if any of these parts, and especially the bones and ligaments, are diseased, they constitute a source of the greatest pain. The necessity of this arrangement is obvious from the protection which the surface of the body requires from violence and heat. Were it not for these body-guards^ we by our other senses should seldom know when friction or heat was consuming the skin, nor when cold was destroying its vitality. 737. Value of this Sense to the Blind. — To those de- prived of the sense of vision, this sense is of great value, since it is by this only that they are enabled to pursue any labor, or instruct and please themselves by raised alphabets, or play upon musical instruments. And it is interesting, not to say wonderful, to see what accuracy is acquired by the blind in detecting true from spurious coins, or in distinguishing the quality of cloth by feeling alone. It is said on good author- What is the function of the papillre? 736. Why are the superficial parts of the body the most abundantly supplied with sensitive nerves ? Why does the skin need sensibil- ity? 737. What is said of the value of this sense to the blind? What examples are mentioned as illustrating its extreme acuteness in the blind ? 402 HITCHCOCK’S anatomy itj, that one blind man became a botanist, another a con- cbologist, and another a land surveyor, simply by the aid of touch. 738. Effect of Habit on location of Sensation. — Habit has a wonderful power in the location of sensations on the skin. Thus it is frequently the case, after an amputation of a limb, that the patient declares that he feels pain in the re- moved portion. This is owing to some irritation in a fiber or fibers of the remaining nerve trunk, which were originally sent to the supposed seat of the pain, and from habit the suf- ferer locates it in the removed part. Also after the Talia- cotian operation — which consists in making a new nose from the skin of the forehead, — if the nose itches, the patient scratches the forehead as the seat of the irritation. 739. Insensibility produced by a long continued Action of some painful Stimulus.— It is sometimes the case that the nerves are rendered insensible by the moderate but long continued action of some painful stimulus. A com- plete insensibility of the skin may be produced, so that the severest surgical operations may be performed without pain, by the application of snow and salt mixed in equal portions. Heat will also do the same thing, as shown by the following example. A traveling man one winter’s evening laid him- self down upon the platform of a lime kiln, placing his feet, ^ probably benumbed by the cold, upon the heap of stones newly put on to burn through the night. Sleep overcame him in this situation : the fire gradually rising and increasing, until it ignited the stones upon which his feet were placed. Lulled by the warmth the man slept on ; the fire increased until it burned one foot and part of the leg above the ancle entirely off, consuming that part so effectually that a cinder- like fragment Avas alone remaining, and still the Avretch slept on, and in this state Avas found by the kiln man in the morn- 73*^. AVliat cfToct hns liahit upon localizing our sensations? 739. How may insensibility bo BomoUniea broufjht about ? What wonderful example ? AND PHYSIOLOGY. 403 ing. Insensible to any pain, and ignorant of his misfortune, he attempted to rise and resume his journey, but missing his shoe, requested to have it found : and when he was raised, putting his burnt limb to the ground to support his body, the extremity of his leg bone — the tibia — crumbled into frag- ments, having been calcined into lime. Still he expressed no sense of pain, and. probably experienced none, from the grad- ual operation of the fire, and his own torpidity during the hours his foot was consuming.’’ THE SENSE OF TOUCH IN ANIMALS. 740. ‘^It is probable that among the lower animals the proportion of intuitive perceptions is much greater than in man ; whilst on the other hand his power of acquiring per- ceptions is much greater than theirs.” 741. Touch in Mammals.— Cat, Rabbit, Elephant, Bat. — Among Mammals touch ordinarily depends on little projections known as papillae, which contain a loop of a sensi- tive nerve. In man this structure is principally found in the tips of the fingers, but in the Monkey it is found in both the hands and feet. In a majority of mammals the surface of the nose, upper lip, and the vibrissae or whiskers, as seen on the face of the cat, are organs adapted to the sense of touch. Cats are unable to catch mice when these whiskers are removed, and Rabbits without the assistance of their eyes can by means of these hairs find an outlet in a very narrow passage. In the Elephant this sense has its seat at the ex- tremity of the proboscis. The wing of the Bat possesses an extraordinary sensitive power. It is said that this animal is T40. What is said of the intuitive perceptions of the lower animals ? T41. Where is the sense of touch most perfectly developed in a^nimals ? Of what use are the whiskers of the cat and rabbit ? Where is the sense of touch in the elephant ? 404 HITCHCOCK’S ANATOMY able to fly through perfectly dark and irregular narrow pas- sages, and avoid all obstructions simply by the delicate sensi- bility of its membranous wings. 742. Touch in Birds. — The only portions of the skin in Birds, on which tactile papillae exist, are found on the under surface of the foot, and the web of the web-footed birds. The bill of the Duck seems also to subserve the sense of touch, upon the inside of which the skin is soft, and has many branches of the fifth pair of nerves distributed to it. 743. Touch of Reptiles. — The sense of touch seems to exist in Reptiles, though the prominent use of the skin is to afford a protection to the body. It is quite probable that the acuteness of this sense in these animals is no greater than what is derived to the Horse through the hoof, or to a man through a stick or rod in the hand. 744. Touch of Fishes. — Fishes probably have a still more imperfect sense of touch than Reptiles. It is pos- sible that the lips may give an imperfect idea of the form of external objects; but the surface of the body, covered as it is with scales and a thick mucous secretion, can be of no service in this sense. A few fishes have hair-like appendages about the head, which put them in a condition to be acquainted with the presence of external objects, though they are not by any means organs of active touch. 745. Touch of Articulates. — This sense is well devel- oped in all the Articulates, and shows itself especially in the antennae, the palpi, and feet ; and though these organs have a tough, hair-like consistence, yet they are efficient instru- Wlierc in the bat? 742. Where are papillse found in birds? WTiat answers the pur- pose of papill»3 in the duck? 743. What is said of the sense of touch in reptiles? 744. Where is the sense of touch located iu fishes ? 745. Describe the sense of touch in articu- lates. AND PHYSIOLOGY, 405 merits of sensation. “ For just as a blind man judges of the proximity and char- acter of objects by the impressions com- municated to his hand by the contact of his cane, with which he examines them, so may an insect or crustacean receive sensory impressions from the nerves dis- tributed to the basal joints of their long antenna 0 , although the organs themselves may be as insensible (or rather as un- impressible) as the stick.’’ 746. Touch of Molluscs. — The sense of touch in this group is well developed. In some of the orders the organs are from two to four contractile tentacles situated upon the head, or the anterior part of the back.” With some Gas- teropods these tentacles are hollow and button-like at tlieir extremity, and can be inverted like the finger of a glove.’" 747. Touch of Ra(liates^ — ‘‘The sense of touch is well developed among the Echinoderms.” It exists here and among other Radiates in tentacles or feelers. Besides this, other individual Radiates seem to possess a sensitiveness of the whole surface of the body, though nerves can not be the agents which secure this sense to them. Is it by an active touch that this sensation is gained by articulates ? 746, Describe touch in molluscs. 747. What is the touch of radiates ? Fig. 367. 400 niTon cock’s anatomy SENSE OF TASTE. DEFINITIONS AND DESCRIPTIONS. 748. Anatomy of the Tong nentlj the organ of taste. Its Fig. 368. 10 Front View of the Upper Surface of the Tongue, as well as the Palatine Arch. 1, 1, Posterior Lateral Half Arches, with the Palato- Pharyngeal Muscles and Tonsils. 2» Epiglottic Cartilage, seen from before. 3, 3, Ligament and Mucous Membrane, ex- tending from the root of the tongue to the base of the Epiglottic Cartilage. 4, One of the Pouches on the Side of the Posterior Fia?nurn, in which food sometimes lodges. 6, Foramen Caecum. 6, Papillaj Capitatae scu Maximae. 7, The white point at the end of the line, and all like it, are the Pa- pillae Fungiformes. 8, Side of the Tongue and lliigae Transvers.'c of Albinus. 9, Pa- idlhc Filiformes. 10, Point of the Tongue. ne. — The tongue is preCmi- principal part is made up of muscular fibers which run in various directions, although they run in similar directions upon the opposite halves of this organ. The tongue is covered with a thick mucous membrane, which contains a large number of papillae simi- lar to those of the skin, which are of three kinds, the Filiform, Fungiform, and Circum vallate. The filiform are from one thirty-sixth to one eighth of an inch long, of a conical shape, and are most abundant on the middle portion of the tongue. The fungiform are situated upon the tip and sides of the tongue, and are some- what smaller than the filiform. The circumvallate are from six to twelve in number, and are arranged upon the base of the tongue in the form of the letter V, the apex pointing downwards. They consist of a central round papilla flat- 748. Wliiit Is the organ of taste ? Of what is it made up, and with what is it covered ? Name the three kind* of papilluj. Describe the Uliform, fungiform, and circumvallate. AND PHYSIOLOGY. 407 tened at the end, one twenty-fourth to one twelfth of an inch in diameter, with a lower uniform wall closely surrounding the papilla. More nerves are distributed to the circumvallate than to either of the other forms of papillae. At its lower or posterior extremity the tongue is attached to the os hyoides, and at its lower front portion to the lower jaw by the fraenum or bridle of the tongue ; so that it is left free to move ei- ther backwards or for- wards by the contrac- tion of the appropriate muscles. Fig. 369. One of the smallest Pai)illa3 of the Tongue highly Magnified. 749. Blood-Vessels of this Organ —A great quantity of blood-vessels are distributed to this organ, as can be seen by looking at the under side of it, as well as by the free flow of blood when it is wounded. 750. Nerves of Taste. — Of nerves there are no less than three large branches supplied to the tongue from the cranial group : the gustatory or proper nerve of taste, a branch of the fifth pair which is distributed to the papillse ; the glosso- pharyngeal distributed to the mucous membrane, being both a nerve of motion and sensation ; and the hypoglossal distrib- uted to the muscles, being preeminently a nerve of motion. FUNCTIONS. 751. Use of the Numerous Muscular Fibers in the Tongue. — To effect the numerous movements of the tongue in Which kind receive the most nerves ? To what is the tongue attached by its lower extremity? 749. What proportion of blood is sent to this organ? 750. How many nerves • are sent to the tongue, and what are they ? 18 408 HITCHCOCK’S ANATOMY mastication, swallowing, tasting, articulation, etc., it is neces- sary that the muscular fibers should run in various directions. That, however, which is commonly known as the tongue is only the tip of it, while the largest portion lies in the front and lower portion of the pharynx, where most of the muscu- lar actions are performed. 752. Use of the Papillae. — The papillae of the tongue, as those of the skin, are constructed for the purpose of giving as much surface of nerve to be exposed as possible, leaving it mostly in t' e form of a loop. The filiform papillae are not the seat of the sense of taste or touch, but arc analogous to the lingual spines of lower animals (which gives such rough- ness to their tongues), which aid in mastication and protec- tion of the tongue. As the sense of touch is most acute at the tip of the tongue, it is supposed that the fungiform papillm are the instruments of touch to the tongue ; and as we acquire the sense of taste more at the base than at the tip of the tongue, and as the nerves are more abundant and finest at the circumvallate papillae, these probably administer mainly to the sense of taste. 753. Object of this Sense. — The main use of this sense is to direct us in the choice of proper articles of food, and by this means to excite the flow of saliva and mucus, to aid in digesting food. In man, however, this sense would be an un- safe guide, since this alone can not aid us to distinguish whole- some from poisonous food, although many of the lower animals seem able to make such a distinction by this sense alone. 754. Effect of Education on Taste. — Taste is made won- derfully acute by education. Epicures are able to tell the manner in which game was killed, the spices used in cooking it, and the length of time since it was killed, when eating it. Tr^l. Why aro there so many muscular fibers in the tongue? Where does the larger ]»oi tlon of this organ lie ? 752. Of what use are the papilhe? What sensation is gained by the filiform papilla;? In what jiapillse docs the sense of taste mainly exist? 753. What is the use of this sense? Is it alone a safe guide for man? 754. What effect has education upon taste? (live Instances. AND PHYSIOLOGY. 400 Wine tasters can readily give differences in the age, growth of the grape, and the purity of wines, that to ordinary observers are imperceptible. 755. Taste as Influenced by Smell.— Taste, as to some substances, is dependent on the sense of smell. Thus, with the eyes and nostrils closed, if an aromatic or spicy substance be chewed it is impossible to say what the substance is, except that it is pungent, although it may be one with which the per- son is well acquainted. Yet smell does not aid us in deter- mining the taste of acids, alkalies, or salts. 756. After-Tastes. — An important point connected with this sense is that known as after-tastes. Thus, frequently after eating sweet substances a bitter taste is left in the mouth, and when bitter substances have been tasted a pleasant and sweet taste is left in the mouth. This subject is a matter of great importance in the art of cookery. THE SENSE OF TASTE IN ANIMALS. 757. Use of the Conical Papillae. — This sense is in aB animals confined to the tongue and inner surface of the mouth. The sensation received from the sapid body is gained through the papillae, which are present on the tongue and in general structure resemble those of the skin. There are probably four kinds in mammals, those upon the central part of the tongue often being conical, hard, and even horny, and those upon the back part fungiform, or soft and cup-shaped, as is seen in the tongue of the cat. The conical papillae seem to act the part of a rasp, especially in the carnivorous animals, in order to remove all the particles of meat from bones. And 755, Give the connection between taste and smell. 756. What is said of after-tastes ? 757. How many kinds of papillae in most mammals? What are the uses of the conical papillae to meat-eating animals? How powerful an instrument do these at times consti- tute ? 410 HITCHCOCK’S ANATOMY SO efficient are these that tlie skin of some of the more deli- cate animals is removed simply by the licking of the tongue of one of the more powerful carnivora. 758. Tongue of Birds — In the Woodpecker and Hum- ming-Bird. — In birds this sense is very feeble, since the tongue is destitute of sensitive papillae, and is often of a hard, horny consistence, designed probably more for the means of obtaining food than of judging of its quality. In some birds the tongue is furnished with one or more ossicles for the pur- pose of giving stability and strength to it. In woodpeckers the tongue is not only long, slender, and stout, but it is armed Fig. 370 . Tongue. Head of the Woodpecker. with appendages like barbs on either side, in order that it may be thrust into narrow crevices in trees, to pierce and hold in- sects upon which it lives. (See Fig. 370.) Humming-birds have tongues very slender and slit at the apex, so that both sides can be formed into a sort of tube by curving them to- gether from the outside, in order that the bird may suck up the nectar of flowers. And in both of these birds the tongue can be extended for a long distance in front of the body. 759. Tongue of Reptiles — Chameleon.— The tongue of most of the class of reptiles seems to be constructed for other purposes than that of taste. Like that of birds, it is pro- vided with one or more lingual (tongue) bones, and is desti- 75^. Ifow is it with the sense of taste in birds ? Describe the tongue of the woodpecker. Wlmt is its use ? What is the tongue of the humming-bird ? How far can the tongue !»<• protruded in either of tlicso animals ? 759. For wdiat purpose is the tongue of rep- t 1 -s ? AND PHYSIOLOGY. 411 tute generally of papillae. In some of this class it is hardly perceptible, while in Serpents, Toads and the Chameleon, it is very long and capable of rapid motion. In Chameleons and Serpents, when the tongue is at rest, it lies in a kind of sheath at the base of the mouth. That of the latter is forked at its apex, while the former has a concave disk at its point covered by a viscid secretion, which, by the dexterity of the animal, can be thrown at once against the insects flying in the air, thus securing its food. In this case also the tongue seems longer than the body itself. Fig. 311. • Tongue of Common Fly. or, Lobes of Lingula. 5, Portion enclosing the Lancets formed by the Metamorphosis of the Maxilla, c, Maxillary Palpi, a, Portion of one of the Metamorphosed Tracheaj enlarged. How does the chameleon obtain his insect food? 7G0. Have fishes any tongue, or the sense of taste? 761. How well is this organ developed in some of the lower animals? 762. Describe the shape of the nose. Of what is it principally composed ? 412 II I T C n C O C K ’ S ANATOMY 760. This sense in fishes appears to be very feeble. “The part named tongue in them consists merely of the anterior ex- tremity of the tongue-bone covered by mucous membrane.” If fishes possess this sense, the palate rather than the tongue is probably its seat. 761. Invertebrates. — Taste, doubtless, exists in all the lower animals else how could they select their food ? The seat of this sense is not always discoverable, as can be done in the Cephalopoda. But the sense exists in all, even in the Protozoa. Fig. 371 exhibits the tongue of the common fly, which is doubtless the seat of this sense. SENSE OF SMELL. DEFINITIONS AND DESCRIPTIONS. 762. Anatomy of the Nose.— The Nose uvhich contains the organs of smelling, is a triangular pyramid placed upon the face, its apex connected with the forehead, and its base descending nearly to a level with the upper lip. It is prin- cipally made up of bone cartilage and integuments, having a thin plate of bone (the vo- mer) and cartilage in the middle which run in a verti- cal direction, and divide the cavity into two portions called the nostrils. (Fig. 372.) A View of the Cartilages of the Nose. 1, The Nasal Bones. 2, The Cartilaginous Septum. 3, The Lateral Cartilages. 4, The Alar Cartilages. 5, The Central por- tions of the Alar Cartilages which consti- tute the Columns. 6. The Appendices of the Alar Cartilage. 7, The Nostrils. AND PHYSIOLOGY. 413 762 a. Use of the Bones. — Use of the Cartilages, and the Glands in Integuments. — The bones are the two nasal, which give form to the base of the nose, and fur- nish a firm attachment to the muscles. The cartilage is of use to give form to the nose, while its elasticity lessens the efiects of injuries. The integument or skin is quite thick upon this organ, and aids the cartilage in giving form to it. It contains in its substance small glands, which secrete an oily matter to protect the nose from extremes of weather. These glands are liable to retain dust and other impurities in their orifices, forming the black specks on the nose. 763. Lined with Mucous Membrane.— The whole cav- ity of the nostrils is lined with mucous membrane, which is continuous with the lining membrane of the fauces or throat, with which the nostrils are in communication. 764. Cavities of the Nostrils. — Nerve of Smelling . — The cavities of the nostrils are very irregular, since upon their own outer sides are found the turbinal bones and a similar scroll-like por- tion from the ethmoid bone, for the purpose of giving as large a surface as possible for the expan- A Vertical Section of the Middle Part of the Nasal Fossae, giving a Posterior View of the Arrangement of the Ethmoidal Cells, etc. 1, Anterior Fossaj of the Cranium. 2, The same covered by the Dura Mater. 8, The Dura Mater turned up. 4, Tlie Crista Galli of the Ethmoid Bone. 5, Its Cribriform Plate. 6, Its Nasal Lamella. 7, The Middle Si>ongy Bones. 8, The Ethmoidal Cells. 9, The Os Planum. 10, Inferior Spongy Bone. 11, The Vomer. 12, Superior Maxillary Bone. 13, Its Union with the Ethmoid. 14, Anterior Parietes of the Antrum Highmoriauurn, covered by its Membrane. 15, Its Fibrous Layer 16, Its Mucous Membrane. 17, Palatine Process of the Superior Maxil- lary Bone. 18, Eoof of the Mouth, covered by the Mucous Membrane. 19, Section of this Membrane. A Bristle is seen in the Orifice of the Antrum llighmorianum. 762 a. State the use of bone and cartilage in the composition of the nose. Of what ser- vice are the little glands in its skin? 763. What are the nostrils lined with? 7G4. De- scribe the cavities of the nostrils. FiU. 3*73. 414 HITCHCOCK’S ANATOMY sion of the nerve of smell, and at the same time furnishing such an arrangement, that the air containing the odor can be readily drawn over it. This nerve is the Olfactory or first pair of cranial nerves, which, as soon as it reaches the nostrils, is divided into a great number of filaments, and these are dis- tributed upon the mucous membrane — called Pituitary — al- ready described. The fifth pair of cranial nerves also sends branches to this membrane, by means of which it is that sneezing is effected. 765. Smell under the Control of the AVill— The sense of smell is somewhat under the control of the will, since the air containing the odoriferous particles can be carried over the nostrils or rejected at pleasure, and it can also be cultivated to a great extent, although some persons are naturally more sensitive to odors than others. It is related that a gentleman who had a great antipathy to cats, could tell if there was one in the next room by smell alone. And the blind boy Mitchell always formed a favorable or unfavorable impression of a stranger by this sense. THE SENSE OF SMELL IN ANIMALS. 766. The sense of smell is most perfectly developed in air- breathing animals, although many which live in the water, can distinguish odors or scents to a considerable distance. 767. Smell in Mammals. — In Mammalia the mucous membrane covering the turbinal bones is supplied with ol- factive nerves. And in carnivorous animals, like the Lion and Tiger, these bones are split up into several laminae, giving them arborescent or tree-shaped forms, so that the membrane Why arc tho turhlnulbonos placed hero ? What is tho nerve of smelling? 765. To Avhat extent is smell under tho control of the will ? What curious facts in this connec- Ihm ? 760. In what animals is this sense tho most perfectly developed? 767. Among what matiitmils do we find this sense in th-e greatest perfection? What peculiarity in tho turhinal hones in tho Hon ? AND I D YSIOLOGT. 415 may be expanded over as great a surface as possible. The cavities in the bones of the face and skull in these animals, as well as also the Horse and Deer, are very much developed, and all the mammalia, except the Whale tribe, are supplied with a turbinal bone, the cavities of which are lined by a membrane which greatly aids in the sense of smell. The sense of smell is also greatly developed in the timid grazing animals, so that they may in this way receive notice of the approach of their enemies and escape. For most quadrupeds give off a strong odor from their bodies, in the exhalations of the skin. 768. Smell in Birds. — A Nasal Gland. — Birds possess turbinal bones and a large nasal cavity, but it is doubted whether much of the power of discerning their prey de- pends on this sense, or whether it does not entirely depend on vision. For the olfactory nerve merely ramifies upon a part of the nasal cavity, the remaining portion being sup- plied with branches from the fifth pair. There is, how- ever, a peculiar gland called the nasal, which serves the pur- pose of lubricating the pituitary (or mucous) membrane, which is probably necessary from the fact that so much air is con- stantly passing over the nostrils that the membrane 'would otherwise become dry and thus impair the sense of smell. 769. Smell in Reptiles. — Reptiles seem by their organiza- tion of very simple nasal cavities, to have their sense of smell feebly developed. A few only have bony or cartilaginous turbinal organs, and a portion only have the cavities lined by a pituitary membrane ; and from the gormandizing habits of these animals, we see that the sense of smell could be of but little service to them. 770. Smell in Fishes. — Fishes possess a cavity lined by a What bone is the whale tribe wanting in ? How is the sense of smell in grazing ani- mals? 768. How well developed are the organs of smell in birds? What is probably the case with regard to their powers of smell ? What gland is furnished to them which pos- sibly aids this sense ? 769. What is said of this sense among reptiles? Is this sense of any great value to them ? 18 * 416 HITCHCOCK’S A N A T O Y pituitary membrane and furnished with olfactory nerves, which gives them a powerful organ of smell. This cavity, however, has no posterior orifice, its only opening being in front, and the water in it being continually kept in motion by the cilim with which it is lined. In the sharks and rays there is a mus- cular appendage to keep the water in motion, so that Sir Richard Owen says these animals must actively scent (that is search for odoriferous impressions) as well as smell. 771. Artie Ilia t a. — Crustaceans have the sense of smell, and the central ganglion sends off an olfactory nerve. The Arachnoids can smell without any discoverable organ. So also the Insects. Probably all of the Articulates have this sense, but perhaps without special organs. 772. Molluscs . — In Cephalopods olfactory organs are made out, but not in the other classes. 773. Radiata . — No distinct organs for this sense have been found in these animals. But the presumption is that it exists with or without special organs in them all. Of the Protozoa the Infusoria clearly evince sensation and volition ; but no nervous system has been discovered in them, and though it is quite manifest that they are sensible to the contact with objects and to light, yet there is no evidence that they have the sense of smell. Equally probable is it that it is wanting in the Rhizophoda. HYGIENIC INFERENCES IN RESPECT TO THE SENSES. 774. — 1. Moderation in their Use Required. — All the organs of sensation require to be moderately employed. If 770. How Is It with the sense of smell in fishes? What peculiarity amon» the sharks nnd rays? 771. Have articulate animals the power of smelling? Have they the organs a(lai>tc.>ir . •<.; 3j;i.n'4:vr' ;'i‘ov'r: 1 C :r- Ji. ' , ; V. ’-v'V dujj •* •* . . ., . ^ , . ' hU\ ■ •;. . ... ■; ,• - ’ ' . .. - i-.; v aviii \'.j . > !•> - :• '■/ 1 •: > ^ jJ.\ ' 1’ 'I i . l £ i yi ..r j'A'i j.i.r .V,* . {, '•i'j f'. ’! .,;;.;p;oT k. . . 'ij ■■. -Ai'-i. k . ■f