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 THE BRIDGEWATER TREATISES 
 
 ON THE POWER WISDOM AND GOODNESS OF GOD 
 AS MANIFESTED IN THE CREATION 
 
 TREATISE IV 
 
 THE HAND ITS MECHANISM AND VITAL ENDOWMENTS 
 
 AS EVINCING DESIGN 
 BY SIR CHARLES BELL K. G. H. 
 
 F. R. S. L. & E. 
 
 PROF. ROY. COLL. SURG. AND MEM. COUNCIL. 
 
 [THIRD EDITION]
 
 THE HAND 
 
 ITS MECHANISM AND VITAL ENDOWMENTS 
 AS EVINCING DESIGN 
 
 SIR CHARLES BELL K.G.H 
 
 F. R. S. L. & E. 
 
 PROF. ROY. COLL. SURG. AND MEM. COUNCIL. 
 
 LONDON 
 
 WILLIAM PICKERING 
 1834
 
 >K* CntlKT, CHANCRRY I \ M
 
 NOTICE. 
 
 THE series of Treatises, of which the present is one, is 
 published under the following circumstances : 
 
 The RIGHT HONOURABLE and REVEREND FRANCIS 
 HENRY, EARL OF BRIDGEWATER, died in the month of 
 February, 1829 ; and by his last Will and Testament, bear- 
 ing date the 25th of February, 1825, he directed certain 
 Trustees therein named to invest in the public funds the 
 sum of Eight thousand pounds sterling; this sum, with 
 the accruing dividends thereon, to be held at the disposal 
 of the President, for the time being, of the Royal Society 
 of London, to be paid to the person or persons nominated 
 by him. The Testator further directed, that the person or 
 persons selected by the said President should be appointed 
 to write, print, and publish one thousand copies of a work 
 On the Power, Wisdom, and Goodness of God, as mani- 
 fested in the Creation ; illustrating such work by all reason- 
 able arguments, as for instance the variety and formation of 
 God's creatures in the animal, vegetable, and mineral king- 
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 the construction of the hand of man, and an injinite variety 
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 He desired, moreover, that the profits arising from the sale 
 of the works so published should be paid to the authors of 
 the works.
 
 VI 
 
 The late President of the Royal Society, Davies Gilbert, 
 Esq. requested the assistance of his Grace the Archbishop 
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 the Testator. Acting with their advice, and with the con- 
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 deceased, Mr. Davies Gilbert appointed the following eight 
 gentlemen to write separate Treatises on the different 
 branches of the subject as here stated : 
 
 THE REV. THOMAS CHALMERS, D.D. 
 
 PROFESSOR OF DIVINITY IN THg DNIYBR8ITY OF EDINBURGH. 
 
 ON THE POWER, WISDOM, AND GOODNESS OF GOD 
 
 AS MANIFESTED IN THE ADAPTATION 
 
 OF EXTERNAL NATURE TO THE MORAL AND 
 
 INTELLECTUAL CONSTITUTION OF MAN. 
 
 JOHN KIDD, M.D. F.R.S. 
 
 ON THE ADAPTATION OF EXTERNAL NATURE TO THE 
 PHYSICAL CONDITION OF MAN. 
 
 THE REV. WILLIAM WHEWELL, M. A. F.R.S. 
 
 I I I I ou OK TRINITY COLLEGE, CAMBRIDGE. 
 
 ASTRONOMY AND GENERAL PHYSICS CONSIDERED WITH 
 REFERENCE TO NATURAL THEOLOGY. 
 
 SIR CHARLES BELL, K.G.H. F.R.S. L.&E. 
 
 THE HAND: ITS MECHANISM AND VITAL ENDOWMENTS 
 AS EVINCING DESIGN. 
 
 PETER MARK ROGET, M.D. 
 
 FELLOW OF \M' SECRETARY TO THE ROYAI. SOCIETY. 
 
 ON ANIMAL AND VEGETABLE PHYSIOLOGY.
 
 Vll 
 THE REV. WILLIAM BTJCKLAND, D.D. F.R.S. 
 
 CANON OF CHRIST CHURCH, AND PROFESSOR OF GEOLOGY IN THE 
 
 ON GEOLOGY AND MINERALOGY. 
 
 THE REV. WILLIAM KIRBY, M.A. F.R.S. 
 
 ON THE HISTORY, HABITS, AND INSTINCTS OF ANIMALS. 
 
 WILLIAM PROUT, M.D. F.R.S. 
 
 CHEMISTRY, METEOROLOGY, AND THE FUNCTION OF 
 
 DIGESTION, CONSIDERED WITH REFERENCE 
 
 TO NATURAL THEOLOGY. 
 
 His ROYAL HIGHNESS THE DUKE OF SUSSEX, Presi- 
 dent of the Royal Society, having desired that no unneces- 
 sary delay should take place in the publication of the 
 above mentioned treatises, they will appear at short inter- 
 vals, as they are ready for publication.
 
 PREFACE. 
 
 WHEN one has to maintain an argument, he 
 will be listened to more willingly if he is 
 known to be unbiassed, and to express his 
 natural sentiments. The reflections contained 
 in these pages have not been suggested by 
 the occasion of the Bridgewater Treatises, 
 but arose, long ago, in a course of study, 
 directed to other objects. An anatomical 
 teacher, who is himself aware of the higher 
 bearings of his science, can hardly neglect 
 the opportunity which the demonstrations 
 before him afford, of making an impression 
 upon the minds of those young men who, 
 for the most part, receive the elements of 
 their professional education from him ; and he 
 is naturally led to indulge in such trains of 
 reflection as will be found in this essay. 
 
 So far back as the year 1813, the late 
 excellent vicar of Kensington, Mr. Rennell, 
 attended the author's lectures, and found him 
 engaged in maintaining the principles of the 
 English school of Physiology, and in ex- 
 posing the futility of the opinions of those
 
 X PREFACE. 
 
 French philosophers and physiologists, who 
 represented life as the mere physical result 
 of certain combinations and actions of parts, 
 by them termed Organization. 
 
 That gentleman thought that the subject 
 admitted of an argument which it became 
 him to use, in his office of " Christian Advo- 
 cate."* This will show the reader that the 
 sentiments and the views, which a sense of 
 duty to the young men about him induced 
 the author to deliver, and which Mr. Rennell 
 heard only by accident, arose naturally out 
 of those studies. 
 
 It was at the desire of the Lord Chancellor 
 that the author wrote the essay on " Animal 
 Mechanics ;" and it was probably from a 
 belief that the author felt the importance of 
 the subjects touched upon in that essay, that 
 his lordship was led to do him the further 
 honour of asking him to join with him in 
 illustrating the " Natural Theology" of 
 Dr. Paley. 
 
 That request was especially important, as 
 showing that the conclusions to which the 
 author had arrived, were not the peculiar or 
 accidental suggestions of professional feeling, 
 nor of solitary study, which is so apt to lead 
 
 * An office in tlie University of Cambridge.
 
 PREFACE. XI 
 
 to enthusiasm, but that the powerful and 
 masculine mind of Lord Brougham was di- 
 rected to the same object : that he, who in 
 early life was distinguished for his successful 
 prosecution of science, and who has never 
 forgotten her interests amidst the most ar- 
 duous and active duties of his high station, 
 encouraged and partook of these sentiments. 
 
 Thus, from at first maintaining that design 
 and benevolence were every where visible in 
 the natural world, circumstances have gra- 
 dually drawn the author to support these 
 opinions more ostentatiously and elaborately 
 than was his original wish. 
 
 The subject which he has to illustrate in 
 this volume, belongs to no definite depart- 
 ment; and is intermediate between those 
 sciences which have been assigned to others. 
 The conception which he has formed of 
 its execution is, that setting out as from a 
 single point, he should enlarge his survey and 
 show the extent of the circle, and the variety 
 of subjects which it bears upon ; thence de- 
 ducing the conclusion, that as there is a rela- 
 tion of one part to the whole, there must be a 
 system, arid universal design. 
 
 The author cannot conceal from himself the 
 disadvantages to which he is exposed in
 
 Xll PREFACE. 
 
 coming before the public, not only with a 
 work, in some measure extra-professional, 
 but with associates, distinguished by clas- 
 sical elegance of style, as well as by science. 
 He must entreat the reader to remember that 
 he was, early and long, devoted to the study 
 of anatomy; and with a feeling (right or 
 wrong) that it surpassed all other studies, in 
 interest and usefulness. This made him neg- 
 ligent of those acquirements which would 
 have better fitted him for the honourable 
 association in which he has been placed : 
 and no one can feel more deeply that the 
 suggestions which occur in the intervals of 
 an active professional life, must always be 
 unfavorably contrasted with what comes of 
 the learned leisure of a College. 
 
 The author has to acknowledge his obliga- 
 tions to His Grace the Archbishop of Canter- 
 bury, the Bishop of London, and the late 
 President of the Royal Society, for having 
 assigned to him a task of so much interest. 
 When he undertook it, he thought only of 
 the pleasure of pursuing these investigations, 
 and perhaps too little of what the public were 
 entitled to expect from an Essay composed 
 in circumstances so peculiar, and forming a 
 part in " this great argument."
 
 CONTENTS. 
 
 Page 
 
 CHAP. I. INTRODUCTORY Object of the Volume , . 1 
 Consequence of viewing the Animal Body as a 
 
 Machine -. I > I 1 . ; . ; -r '! 3 
 Relations of the Human Body to the surrounding 
 
 Elements . ' '. . . . . . . 5 
 
 Complexity of Structure consequent upon these 
 
 relations . ' : *.' '. '. ' . . 8 
 The Systematic Arrangement in an Animal Body 
 
 implies a more universal design t; A" ;V . 9 
 Insensibility to the Provisions for Life and Security 
 
 a species of ingratitude . : . V; : : ' : 13 
 
 CHAP. II. DEFINITION OF THE HAND ... 18 
 
 Its Mechanism . . .- \ .*''- ;*. u;>;.i . 20 
 
 Conformity of the Skeleton to the Extremity : 2 1 
 
 Bones of the Extremity not adapted to Man alone . 22 
 
 Fossil Bones exhibit the Extent of the System . 24 
 These studies not the ground of religious opinion, but 
 
 conducive to a right condition of mind ' *. . . 27 
 Animals the most uncouth, in every Respect adapted 
 
 to their Condition . '. ' .'.' V ';; V,:/ '. 27 
 
 Mistaken Compassion for Animals of peculiar Form 30 
 Animals suited to the progressive Changes of the 
 
 Earth and Elements *. - . . . '' . . 35 
 
 Succession and Grouping of Animals . : : >' - : C J If.'iV 40 
 
 CHAP. III. THE COMPARATIVE ANATOMY OF THE HAND 45 
 
 Comparative View of the Anatomy of the Shoulder 49 
 
 The Arms wanting in a Boy . . . . 55 
 
 The Structure of the Horse's Shoulder . . 57 
 
 Of the Elephant and Camel . . . . 61
 
 Xv CONTENTS. 
 
 Pf 
 
 In the Batrachia . . . . _. . 64 
 
 In the Chelonian Order 65 
 
 The Humerus. Spirit in which the Demonstration 
 
 should be given 70 
 
 Peculiarities in the Mole . } . . . 73 
 
 Bat . . . J . i ; '. . . 74 
 
 Ant-eater . .... . . . . 76 
 
 Adaptation of the Anatomy in Birds ... 78 
 
 Of the Pterodactyle 83 
 
 The Anatomy of the Fore Arm .... 84 
 
 Conclusions drawn from a Fragment of the Radius . 85 
 
 The Action of the Splint Bone in the Horse . . 93 
 
 Horse's Foot . . . ... . . 94 
 
 Of Ruminants . . . . . . . 96 
 
 Contrast in the Foot of the Elephant and the Camel 100 
 
 Megalonix 102 
 
 Mechanism of the Lion's Claw .... 103 
 
 Criticism by Cuvier 1 04 
 
 The Foot of the Quadrumana . . . .106 
 
 Megatherium 108 
 
 Of Amphibia .109 
 
 Plesiosaurus and Ichthyosaurus . . . .112 
 
 Peculiarities and Provisions of the Human Hand . 114 
 Relations of our subject with Geology evinced in 
 
 the successive revolutions of the earth's surface . 116 
 
 CHAP. IV. OF THE MUSCLES OF THE ARM AND HAND 124 
 Action of the Muscles of the Arm . . .125 
 
 Interchange of Velocity for Force, exemplified in 
 
 the Muscles of the Arm 129 
 
 Illustrated by the Lever and Fly- Wheel . .130 
 Muscles of the Lion's Extremity . . .136 
 
 Vital Property of the Muscles . . . .137 
 Peculiarities in the Circulation of the Extremities as 
 
 subservient to Muscular Action . . .138 
 
 Of the Right and Left Hands . . . .140 
 
 CHAP. V. THE SUBSTITUTION OF OTHER ORGANS FOR 
 
 THE HAND . . 143
 
 CONTKXTS. XV 
 
 Page 
 
 CHAP. VI. THE ARGUMENT PURSUED FROM THE COM- 
 PARATIVE ANATOMY 151 
 
 CHAP. VII. OF SENSIBILITY AND TOUCH . . 170 
 The Sensibility of the Surface compared with that 
 
 of the deeper Parts .' . . . .174 
 
 Pain the Safeguard of the Body . . . .178 
 The protecting Sensibility of the Eye compared with 
 
 the Sensibility of the Heart . . . .182 
 Pleasurable Sensations could not have been the Mo- 
 tives of Action . . . i'. > .;' *. 188 
 
 CHAP. VIII. OF THE SENSES GENERALLY INTRODUC- 
 TORY TO THE SENSE OF TOUCH . . . 191 
 The Sense of Touch . '.'- ' " t : . - ; ? . 198 
 
 Of the Cuticle vv 202 
 
 The Hoofs of Animals and their Sensibility . . 205 
 
 CHAP. IX. OF THE MUSCULAR SENSE . . . 212 
 Of the Sensibility of the Infant to Impressions, and 
 
 gradual Improvement of the Sense of Touch . 212 
 
 Of the sense in Insects and Fishes , ., . 221 
 
 Loss of the Sense ,. ... . ; , . . . . 225 
 
 Pleasures arising from the Muscular Sense . . 227 
 
 CHAP. X. THE HAND NOT THE SOURCE OF INGENUITY 
 OR CONTRIVANCE, NOR CONSEQUENTLY OF 
 MAN'S SUPERIORITY . . . -^ . . 230 
 The Capacities of the Mind correspond with the 
 
 Instrument . . . . . , .. . . .232 
 Instincts. Young of the Alligator ., . . 234 
 Malignant Passions find their Instruments without 
 
 Hands. The Beggar of Moscow , . .235 
 The Subject illustrated by the Organs of Speech . 236 
 Improved Ingenuity defeats the Ancient Arts of 
 
 Design 239 
 
 Expression in the Hand. Quintilian . . . 240 
 Changes in the Globe and successive Epochs . 244 
 
 Concluding Remarks . \ . . . . 250
 
 XVI CONTENTS. 
 
 I'., . 
 
 ADDITIONAL ILLUSTRATIONS. 
 
 THE MECHANICAL PROPERTIES OF THE SOLID STRUC- 
 TURE OF THE ANIMAL BODY CONSIDERED . . 261 
 Substitute for the Skeleton in the Lower Animals . 262 
 Mechanical Properties in Bone, or in the True Ske- 
 leton 4 t 267 
 
 Of the Muscular and Elastic Forces . . * 278 
 On the Position of the Head of Animals, and its Rela- 
 tion to the Spine : in illustration of the Statement 
 made in the body of the Work, that ALL PARTS OF THE 
 SKELETON CORRESPOND WITH EACH OTHER, AND 
 THAT THE VARIATIONS IN THEIR FORM DEPEND 
 SOLELY ON THE FUNCTIONS . . . * . 280 
 IMAGINARY ANIMALS . . ,, v 304 
 
 COMPARISON OF THE EYE WITH THE HAND . ;i 309 
 THE MOTION OF THE EYE CONSIDERED IN REGARD TO 
 
 THE EFFECT OF SHADE AND COLOUR IN A PlCTURE 330 
 EXPRESSION IN THE EYE <t .V 339 
 
 APPENDIX. 
 
 Explanation of Terms .-,,;.. \ 343
 
 THE HAND, 
 
 ITS MECHANISM AND VITAL ENDOWMENTS, 
 AS EVINCING DESIGN. 
 
 CHAPTER I. 
 
 IF we select any object from the whole extent of 
 animated nature, and contemplate it fully and in 
 all its bearings, we shall certainly come to this 
 conclusion : that there is design in the mechan- 
 ical construction, benevolence in the endowments 
 of the living properties, and that good on the 
 whole is the result. We shall perceive that the 
 sensibilities of the body have a relation to the 
 qualities of things external, and that delicacy of 
 texture is, therefore, a necessary part of its con- 
 stitution. Wonderful, and exquisitely constructed, 
 as the mechanical appliances are for the protec- 
 tion of this delicate structure, they are altogether 
 insufficient ; and a protection of a very diiferent 
 kind, which shall animate the body to the utmost 
 B. B
 
 INTRODUCTORY CHAPTER. 
 
 exertion, is requisite for safety. Pain, whilst it 
 is a necessary contrast to its opposite pleasure, 
 is the great safeguard of the frame. Finally, as 
 to man, we shall be led to infer that the pains 
 and pleasures of mere bodily sense (with yet 
 more benevolent intention) carry him onward, 
 through the developement and improvement of 
 the mind, to higher aspirations. 
 
 To comprehend the perfection of the struc- 
 ture even of any single organ of an animal 
 body, we must take it comparatively, that we 
 may see how the same system is adapted to 
 an infinite variety of conditions. This carries 
 us necessarily into a new science, no less than 
 that which regards the changes in the Earth's 
 surface ; and although in this comparison we 
 find that there have been stupendous revolutions 
 indicative of power; it is in contemplating 
 the new forms and adaptations of living and 
 organized matter to these successive changes 
 in the surface of the earth, that we have the best 
 proofs of the continuance of that Power which 
 first created. 
 
 Such is the course of reasoning which I pro- 
 pose to follow in giving an account of the hand 
 and arm, contrasting them, in the first place, 
 with the corresponding parts of living creatures, 
 through all the divisions of the chain of verte- 
 brated animals ; and then taking the hand, not 
 merely as combining the perfections of me-
 
 INTRODUCTORY CHAPTER. 3 
 
 chanical structure, but as possessed of the pro- 
 perty of touch, by which it ministers to and 
 improves every other sense, and constitutes the 
 organ in the body the most remarkable in cor- 
 respondence with man's capacities. 
 
 Some may conceive that as I have for my title 
 the Human Hand, and the relation of the solid 
 structures of the animal frame, it will lead me to 
 consider the body as a machine only. I neither 
 see the necessity for this, nor do I acknowledge 
 the danger of considering it in that light. I em- 
 bark fearlessly in the investigation, convinced 
 that, yielding to the current of thought, and 
 giving the fullest scope to enquiry, there can 
 be no hidden danger if the mind be free from 
 vicious bias. I cannot see how scepticism should 
 arise out of the contemplation of the structure 
 and mechanism of the animal body. 
 
 Let us for a moment think what is the natural 
 result of examining the human body as a piece 
 of machinery, and let us see whether it makes 
 the creation of man more or less important in 
 his relation to the whole scheme of nature. 
 
 Suppose that there is placed before us a ma- 
 chine for raising great weights, be it the simplest 
 of all, the wheel and axle. We are given to 
 understand that this piece of mechanism has the 
 property of multiplying the power of the hand. 
 But a youth of subtile mind may say, I do not 
 believe that it is possible so to multiply the
 
 4 INTRODUCTORY CHAl'TF.R. 
 
 power of the hand ; and if the mechanician be a 
 philosopher, he will rather applaud the spirit of 
 doubt. If he condescend to explain, he will 
 say, that the piles driven into the ground, or the 
 screws which unite the machinery to the beams, 
 are the fixed points which resist in the working 
 of the machine ; that their resistance is a neces- 
 sary condition, since it is thrown, together with 
 the power of the hand, on the weight to be 
 raised ; and he will add that the multiplication of 
 wheels does not alter the principle of action, 
 which every one may see in the simple lever, to 
 result from the resistance of the fulcrum or point, 
 on which it rests. 
 
 Now grant that man's body is a machine, 
 where are the points of resistance ? are they not 
 in the ground he stands upon ? This leads us to 
 enquire by what property we stand. Is it by 
 the weight of the body, or, in other words, is 
 it by the attraction of the earth? The terms 
 attraction, or gravitation lead at once to the 
 philosophy of the question. We stand because 
 the body has weight, and a resistance, in pro- 
 portion to the matter of the animal frame and 
 the magnitude of the globe itself. We need not 
 stop at present to observe the adjustment of the 
 strength of the frame, the resistance of the 
 bones, the elasticity of the joints, and the power 
 of the muscles, to the weight of the whole. Our
 
 INTRODUCTORY CHAPTER. 5 
 
 attention is directed to the relations which the 
 frame has to the earth we are placed upon. 
 
 Some philosophers, who have considered the 
 matter curiously, have said, that if man were 
 translated bodily to another planet, and were 
 it smaller than the earth, he would be too light, 
 and he would walk like one wading in deep 
 water. If the planet were larger, the attraction 
 of his body would make him feel as if his limbs 
 were loaded with lead ; nay, the attraction might 
 be so great as to destroy the fabric of the body, 
 crushing bones and all.* 
 
 However idle these fancies maybe, there is no 
 doubt that the animal frame is formed with a due 
 relation to the earth we inhabit, and that the 
 parts of the animal body, and we may say the 
 strength of the materials, have as certainly a 
 correspondence with the weight, as the wheels 
 and levers of a machine, or the scaffolding which 
 sustains them, have relation to the force and 
 velocity of the machinery, or the load that they 
 are employed to raise. 
 
 The mechanism and organization of animals 
 have been often brought forward for a different 
 purpose from that for which I use them. We 
 find it said, that it is incomprehensible that an all 
 
 * The matter of Jupiter is as 330,600 to 1000 of our Earth. 
 The diameter of Pallas is 80 miles; the Earth is 7,911 miles in 
 diameter.
 
 INTRODUCTORY CHAPTER. 
 
 powerful Being should manifest his will in this 
 manner; that mechanical contrivance implies 
 difficulties overcome : and how strange it is, they 
 add, that the perceptions of the mind, which 
 might have been produced by some direct means, 
 or have arisen spontaneously, are received through 
 an instrument so fine and complex as the eye ; 
 and which requires the creation of the element of 
 light, to enter the organ and to cause vision. 
 
 For my own part, I think it most natural to 
 contemplate the subject quite differently. We 
 perhaps presume too much, when we say that 
 light has been created for the purpose of vision. 
 We are hardly entitled to pass over its properties 
 as a chemical agent, its influence on the gases, 
 and, in all probability, on the atmosphere, its 
 importance to vegetation, to the formation of the 
 aromatic and volatile principles, and to fructifi- 
 cation, its influence on the animal surface by 
 invigorating the circulation, and imparting health. 
 In relation to our present subject, it seems more 
 rational to consider light as second only to attrac- 
 tion, in respect to its importance in nature, and as 
 a link connecting systems of infinite remoteness. 
 
 To have a conception of this we must tutor 
 our minds, and acquire some measure of the 
 velocity of light, and of the space which it 
 fills. It is not sufficient to say that it moves 
 200,000 miles in a second ; for we can compre- 
 hend no such degree of velocity. If we are
 
 INTRODUCTORY CHAPTER. 7 
 
 further informed that the earth is distant from 
 the sun 95,000,000 of miles, and that light tra- 
 verses the space in 8 minutes and l-8th, it is but 
 another way of affirming the inconceivable rapi- 
 dity of its transmission. Astronomers, whose 
 powers of mind afford us the very highest 
 estimate of human faculties, whose accuracy of 
 calculation is hourly visible to us, have affirmed 
 that light emanates from celestial bodies at such 
 vast distance, that thousands of years shall 
 elapse during its progress to our earth : yet 
 matter impelled by a force equal to its transmis- 
 sion through this space, enters the eye, and 
 strikes upon the delicate nerve with no other 
 effect than to produce vision.* 
 
 Instead of saying that light is created for the 
 eye, and to give us the sense of vision, is it 
 not more conformable to a just manner of consi- 
 dering these things that our wonder and our 
 admiration should fix on the fact, that this 
 small organ, the eye, is formed with relation to a 
 creation of such vast extent and grandeur : and 
 more especially, that the ideas arising in the mind, 
 through the influence of that matter and this 
 organ, are constituted a part of this vast whole ! 
 
 By such considerations we are led to contem- 
 plate the human body in its different relations. 
 The magnitude of the earth determines the 
 
 * The argument is not weakened on assuming the hypothesis, 
 that light results from the movement of an elastic ether.
 
 8 INTRODUCTORY CHAPTER. 
 
 strength of our bones, and the power of our 
 muscles; so must the depth of the atmosphere 
 determine the condition of our fluids, and the 
 resistance of our blood vessels ; the common act 
 of breathing, the transpiration from the surfaces, 
 must bear relation to the weight, moisture, and 
 temperature of the medium which surrounds us. 
 A moment's reflection on these facts proves to us 
 that our body is formed with a just correspondence 
 to all these external influences : and not the 
 frame of the body only, but also the vital endow- 
 ments and the properties of the organs of sense. 
 It were a perverseness to say that the outward 
 senses, the organization, and vital properties could 
 arise from the influence of the surrounding ele- 
 ments, or out of matter spontaneously ; they are 
 created in accordance with the condition of the 
 globe, and are systematic parts of a great whole. 
 These views lead us to another consideration, 
 that the complexity of our structure belongs to 
 external nature, and not of necessity to the mind. 
 Whilst man is an agent in a material world, 
 and sensible to the influence of things external, 
 complexity of structure is a necessary part of his 
 constitution. But we do not perceive a relation 
 between this complexity and the mind. From 
 aught that we learn by this mode of study, the 
 mind may be as distinct from the bodily organs 
 as are the exterior influences which give them 
 exercise.
 
 INTRODUCTORY CHAPTER. 9 
 
 Something, then, we observe to be common to 
 our planet and to others, to our system and to 
 other systems ; matter, attraction, light ; which 
 nearly implies that the mechanical and chemical 
 laws must be the same throughout. It is perhaps 
 too much to affirm, with an anonymous author 
 that an inhabitant of our world would find him- 
 self at home in any other, that he would be like 
 a traveller only, for a moment perplexed by 
 diversity of climate and strangeness of manners, 
 and confess, at last, that nature was every where 
 and essentially the same. However this may 
 be, all I contend for is, the necessity of certain 
 relations being established between the planet 
 and the frames of all which inhabit it ; between 
 the great mass and the physical properties of 
 every part ; that in the mechanical construction 
 of animals, as in their endowments of life, they 
 are created in relation to the whole, planned 
 together and fashioned by one Mind. 
 
 A comparison made between the system of an 
 animal body, and the condition of the earth's sur- 
 face, is highly illustrative of design in both. In 
 the animal, we see matter withdrawn from the in- 
 fluences which arrange things that are dead and 
 inorganic ; but this matter thus appropriated to 
 the animal, and newly endowed through the 
 influence of life, continues in the possession of 
 such qualities of inanimate matter as are neces- 
 sary to constitute the living being a part of the
 
 10 INTRODUCTORY CHAPTER. 
 
 system an inhabitant of the earth. To what 
 then, does this argument lead ? Is it not, that 
 as the beautiful structure of the animal, and the 
 perfection in the arrangement of its parts de- 
 monstrate design that design extends to the 
 condition of the earth also, and that there is a 
 ruling Intelligence over both ? 
 
 The passiveness which is natural in infancy, and 
 the want of reflection as to the sources of enjoy- 
 ment which is excusable in youth, become insen- 
 sibility and ingratitude in riper years. In the 
 early stages of life, before our minds have the full 
 power of comprehension, the objects around us 
 serve but to excite and exercise the outward 
 senses. But in the maturity of reason, philosophy 
 should present these things to us anew, with this 
 difference, that the mind may contemplate them : 
 that mind which is now strengthened by experi- 
 ence to comprehend them, and to entertain a 
 grateful sense of them. 
 
 It is this sense of gratitude which distinguishes 
 man. In brutes, the attachment to offspring 
 for a limited period is as strong as in him, but it 
 ceases with the necessity for it. In man, on- 
 the contrary, the affections continue, become the 
 sources of all the endearing relations of life, 
 and the very bonds by which society is con- 
 nected.
 
 INTRODUCTORY CHAPTER. 11 
 
 If the child, upon the parent's knee, is uncon- 
 sciously incurring a debt, and strong affections 
 grow up so naturally that nothing is more uni- 
 versally condemned than filial ingratitude, we 
 have but to change the object of affection, to 
 find the natural source of religion itself. We 
 must show that the care of the most tender 
 parent is in nothing to be compared with those 
 provisions for our enjoyment and safety, which 
 it is not only beyond the ingenuity of man to 
 supply to himself, but which he can hardly com- 
 prehend, while he profits by them. 
 
 If man, of all living creatures, be alone 
 capable of gratitude, and through this sense be 
 capable also of religion, the transition is natural ; 
 since the gratitude due to parents is abundantly 
 more owing to Him " who saw him in his blood, 
 " and said, Live." 
 
 For the continuance of life, a thousand provi- 
 sions are made. If the vital actions of a man's 
 frame were directed by his will, they are neces- 
 sarily so minute and complicated, that they 
 would immediately fall into confusion. He 
 cannot draw a breath, without the exercise of 
 sensibilities as well ordered as those of the eye 
 or ear. A tracery of nervous cords unites many 
 organs in sympathy, of which if one filament 
 were broken, pain and spasm, and suffocation 
 would ensue. The action of his heart, and the 
 circulation of his blood, and all the vital func-
 
 12 INTRODUCTORY CHAPTER. 
 
 tions are governed through means and by laws 
 which are not dependant on his will, and to 
 which the powers of his mind are altogether 
 inadequate. For had they been under the 
 influence of his will, a doubt, a moment's pause 
 of irresolution, a forgetfulness of a single action 
 at its appointed time, would have terminated his 
 existence. 
 
 Now, when man sees that his vital operations 
 could not be directed by reason that they are 
 constant, and far too important to be exposed to 
 all the changes incident to his mind, and that 
 they are given up to the direction of other 
 sources of motion than the will, he acquires 
 a full sense of his dependance. If man be 
 fretful and wayward, and subject to inordinate 
 passion, we perceive the benevolent design in 
 withdrawing the vital motions from the influence 
 of such capricious sources of action, so that 
 they may neither be disturbed like his moral 
 actions, nor lost in a moment of despair. 
 
 Ray, in speaking of the first drawing of 
 breath, delivers himself very naturally : " Here, 
 " methinks, appears a necessity of bringing in 
 " the agency of some superintendent intelligent 
 " being, for what else should put the diaphragm 
 " and the muscles serving respiration in motion 
 " all of a sudden so soon as ever the foetus is 
 " brought forth ? Why could they not have 
 " rested as well as they did in the womb ? What
 
 INTRODUCTORY CHAPTER. 13 
 
 " aileth them that they must needs bestir them- 
 u selves to get in air to maintain the creature's 
 " life ? Why could they not patiently suffer it 
 " to die ? You will say the spirits do at this 
 " time flow to the organs of respiration, the 
 " diaphragm, and other muscles which concur to 
 " that action and move them. But what raises 
 " the spirits which were quiescent, &c., I am 
 " not subtile enough to discover." 
 
 We cannot call this agency, a new intelligence 
 different from the mind, because, independently 
 of consciousness, we can hardly so define it. 
 But there is bestowed a sensibility, which being 
 roused (and it is excited by the state of the 
 circulation,) governs these muscles of respiration, 
 and ministers to life and safety, independently 
 of the will. 
 
 When man thus perceives, that in respect to all 
 these vital operations he is more helpless than 
 the infant, and that his boasted reason can 
 neither give them order nor protection, is not his 
 insensibility to the Giver of these secret endow- 
 ments worse than ingratitude? In a rational 
 creature, ignorance of his condition becomes a 
 species of ingratitude ; it dulls his sense of bene- 
 fits, and hardens him into a temper of mind with 
 which it is impossible to reason, and from which 
 no improvement can be expected. 
 
 Debased in some measure by a habit of inatten- 
 tion, and lost to all sense of the benevolence of
 
 14 INTRODUCTORY CHAPTER. 
 
 the Creator, he is roused to reflection only by 
 overwhelming calamities, which appear to him 
 magnified and disproportioned ; and hence arises 
 a conception of the Author of his being more in 
 terror than in love. 
 
 There is inconsistency and something of the 
 child's propensities still in mankind. A piece of 
 mechanism, as a watch, a barometer, or a dial, 
 will fix attention a man will make journeys to 
 see an engine stamp a coin, or turn a block ; yet 
 the organs through which he has a thousand 
 sources of enjoyment, and which are in them- 
 selves more exquisite in design and more curious 
 both in contrivance and in mechanism, do not 
 enter his thoughts ; and if he admire a living 
 action, that admiration will probably be more 
 excited by what is uncommon and monstrous, 
 than by what is natural and perfectly adjusted 
 to its office by the elephant's trunk, than by the 
 human hand. This does not arise from an un- 
 willingness to contemplate the superiority or dig- 
 nity of our own nature, nor from an incapacity 
 of admiring the adaptation of parts. It is the 
 effect of habit. The human hand is so beautifully 
 formed, it has so fine a sensibility, that sensibility 
 governs its motions so correctly, every effort of 
 the will is answered so instantly, as if the hand 
 itself were the seat of that will ; its actions are so
 
 INTRODUCTORY CHAPTER. 15 
 
 powerful, so free, and yet so delicate, that it seems 
 to possess a quality instinct in itself, and there is 
 no thought of its complexity as an instrument, or 
 of the relations which make it subservient to the 
 mind ; we use it as we draw our breath, uncon- 
 sciously, and have lost all recollection of the 
 feeble and ill-directed efforts of its first exercise, 
 by which it has been perfected. Is it not the 
 very perfection of the instrument which makes 
 us insensible to its use ? A vulgar admiration is 
 excited by seeing the spider-monkey pick up 
 a straw, or a piece of wood, with its tail; or 
 the elephant searching the keeper's pocket with 
 his trunk. Now, fully to examine the peculiarity 
 of the elephant's structure, that is to say, from 
 its huge mass to deduce the necessity for its form, 
 and from the form the necessity for its trunk, 
 would lead us through a train of very curious 
 observations to a more correct notion of that 
 appendage, and therefore to a truer admiration 
 of it. But I take this part in contrast with the 
 human hand, merely to show how insensible we 
 are to the perfections of our own frame, and to 
 the advantages attained through such a form. 
 We use the limbs without being conscious, or, 
 at least, without any conception of the thousand 
 parts which must conform to a single act. To 
 excite our attention, we must either see the 
 actions of the human frame performed in some
 
 10 INTRODUCTORY CHAPTER. 
 
 mode, strange and unexpected, such as may 
 raise the wonder of the ignorant and vulgar ; or 
 by an effort of the cultivated mind, we must 
 rouse ourselves to observe things and actions, of 
 which, as we have said, the sense has been lost 
 by long familiarity. 
 
 In the following pages, I shall treat the sub- 
 ject comparatively, and exhibit a view of the 
 bones of the arm, descending from the human 
 hand to the fin of the fish. I shall in the next 
 place review the actions of the muscles of the 
 arm and hand ; then proceeding to the vital pro- 
 perties, I shall advance to the subject of sensi- 
 bility, leading to that of touch; afterwards, I 
 shall show the necessity of combining the mus- 
 cular action with the exercise of the senses, and 
 especially with that of touch, to constitute in 
 the hand what has been called the geometrical 
 sense. I shall describe the organ of touch, the 
 cuticle and skin, and arrange the nerves of the 
 hand according to their functions. I shall then 
 enquire into the correspondence between the 
 capacities and endowments of the mind, and the 
 external organs, and more especially the proper- 
 ties of the hand ; and conclude by showing that 
 animals have been created with a reference to the 
 globe they inhabit ; that all their endowments and 
 various organization bear a relation to their state 
 of existence, and to the elements around them ; 
 that there is a plan universal, extending through
 
 INTRODUCTORY CHAPTER. 
 
 17 
 
 all animated nature, and which has prevailed in 
 the earliest condition of the world ; and that, 
 finally, in the most minute or most comprehen- 
 sive study of those things we every where see 
 prospective design.
 
 CHAPTER II. 
 
 WE ought to define the hand as belonging ex- 
 clusively to man corresponding in sensibility 
 and motion with that ingenuity which converts 
 the being who is the weakest in natural defence, 
 to the ruler over animate and inanimate nature. 
 If we describe the hand as that extremity 
 which has the thumb and fingers opposed to 
 each other, so as to form an instrument of pre- 
 hension, we embrace in the definition the extre- 
 mities of the quadrumana or monkeys. But 
 the possession of four hands by animals of that 
 class implies that we include the posterior as 
 well as the anterior extremities. Now the ante- 
 rior extremity of the monkey is as much a foot 
 as the posterior extremity is a hand ; both are 
 calculated for their mode of progression, climb- 
 ing, and leaping from the branches of trees, just
 
 THE HAND, ITS MECHANISM, ETC. 
 
 19 
 
 as the tail in some species is converted to the 
 same purpose, and is as useful an instrument of 
 suspension as any of the four extremities.* 
 
 The armed extremities of a variety of animals 
 give them great advantages ; but if man pos- 
 sessed any similar provisions, he would forfeit 
 his sovereignty over all. As Galen, long since, 
 observed, " did man possess the natural armour of 
 
 * This is a sketch of the Coaita, or Spider Monkey, so called 
 from the extraordinary length of its extremities, and its motions. 
 The tail answers all the purposes of a hand, and the animal throws 
 itself about from branch to branch, sometimes swinging from the 
 foot, sometimes by the fore extremity, but oftener and with a 
 greater reach by the tail. The prehensile part of the tail is 
 covered only with skin, forming an organ of touch, as discrimi- 
 nating as the proper extremities. The Caraya, or Black howling
 
 20 THE WHOLE SKELETON 
 
 the brutes, he would no longer work as an 
 artificer, nor protect himself with a breast-plate, 
 nor fashion a sword or spear, nor invent a bridle 
 to mount the horse and hunt the lion. Neither 
 could he follow the arts of peace, construct the 
 pipe and lyre, erect houses, place altars, inscribe 
 laws, and through letters and the ingenuity of 
 the hand hold communion with the wisdom of 
 antiquity, at one time to converse with Plato, 
 at another with Aristotle, or Hippocrates." 
 
 But the hand is not a distinct instrument ; nor 
 is it properly a superadded part. The whole 
 frame must conform to the hand, and act with 
 reference to it. Our purpose will not be answered 
 by examining it alone ; we must extend our 
 views to all those parts of the body which are in 
 strict connexion with the hand. For example, 
 the bones from the shoulder to the finger ends, 
 have that relation which makes it essential to 
 examine the whole extremity ; and in order fully 
 to comprehend the fine arrangement of the parts 
 necessary to the motions of the fingers, we must 
 also compare the structure of the human body 
 with that of other animals. 
 
 monkey of Cumana, when shot, is found suspended by its tail 
 round a branch. Naturalists have been so struck with the pro- 
 perty of the tail of the Ateles, as to compare it with the proboscis 
 of the elephant ; they have assured us that they fish with it. 
 
 The most interesting use of the tail is seen in the Opossum. 
 The young of that animal entwine their tails around their 
 mother's tail and mount upon her back, where they sit secure, 
 while she escapes from her enemies.
 
 CONFORMS TO THE EXTREMITY. 21 
 
 Were we to limit our enquiry to the bones of 
 the arm and hand in man, no doubt we should 
 soon discover their provisions for easy, varied, 
 and powerful action ; and conclude that nothing 
 could be more perfectly suited to their purposes. 
 But we must extend our views to comprehend a 
 great deal more, a greater design. 
 
 By a skeleton, is understood the system of 
 bones, which being internal, gives the charac- 
 teristic form to the animal, and receives the action 
 of the exterior muscles. This system belongs, 
 however, only to one part of the animal kingdom, 
 that higher division, the animalia vertebrata,* 
 which includes the whole chain of beings, from 
 man to fishes. 
 
 The function the most essential to life is 
 respiration ; and the mode in which this is per- 
 formed, that is to say, the manner in which the 
 decarbonization of the blood is effected through 
 its exposure to the atmosphere, produces a re- 
 markable change in the whole frame-work of 
 the animal body, Man, the mammalia, birds, 
 reptiles, and fishes have much of the mechanism 
 of respiration in common ; and there is a re- 
 semblance through them all, in the texture of 
 the bones, in the action of the muscles, and in 
 the arrangement of the nerves. They all pos- 
 sess the vertebral column or spine ; and the 
 
 * See the Classification at the end of the volume, also the 
 first of the ADDITIONAL ILLUSTRATIONS. 
 B. D
 
 22 THE BONES OF THE EXTREMITY 
 
 existence of this column not only implies an in- 
 ternal skeleton, but that particular frame- work 
 of ribs, which is suited to move in breathing. 
 But the ribs do not move of themselves, they 
 must have appropriate muscles. These muscles 
 must have their appropriate nerves : and for 
 supplying these nerves there must be a spinal 
 marrow. The spinal canal is as necessary to 
 the spinal marrow as the skull is to the brain. 
 So that we come round to understand the neces- 
 sity of a vertebra* to the formation of the spinal 
 marrow ; and the reader may comprehend how 
 much enters into the conception of the anatomist 
 or naturalist, when the term is used, a verte- 
 brated animal, viz : an internal skeleton, a par- 
 ticular arrangement of respiratory organs, and a 
 conformity in the nervous system. 
 
 It is to this superior division that I shall limit 
 myself, in making a review of the bones of the 
 upper extremity. 
 
 Were I to indulge in the admiration naturally 
 arising out of this subject, and point out the 
 strength and the freedom of motion in the upper 
 extremity at the ball and socket joint of the 
 shoulder, the firmness of the articulation of the 
 elbow, and yet how admirably it is suited to the 
 co-operation of the hands, the fineness of the 
 
 Vertebra is the name given to the individual bones of the 
 spine, or back-bone. See the explanation, in the Classification 
 at the end of the volume, of Vertebral Animals.
 
 NOT ADAPTED TO MAN ALONE, 23 
 
 motion of the hand itself, divided among the 
 joints of twenty-nine bones, it might be objected 
 to with some show of reason, and it might be 
 said, The bones and the forms of the joints 
 which you are admiring, are so far from being 
 peculiarly suited to the hand of man, that they 
 may be found in any other vertebrated animal. 
 But this would not abate our admiration, it 
 would only induce us to take a more compre- 
 hensive view of nature, and remind us that our 
 error was in looking at a part only, instead of 
 embracing the whole system ; where by slight 
 changes and gradations hardly perceptible, the 
 same bones are adjusted to every condition of 
 animal existence. 
 
 We recognise the bones which form the upper 
 extremity of man, in the fin of the whale, in the 
 paddle of the turtle, and in the wing of the bird, 
 We see the same bones, perfectly suited to their 
 purpose, in the paw of the lion or the bear, and 
 equally fitted for motion in the hoof of the horse, 
 or in the foot of the camel, or adjusted for climb- 
 ing or digging in the long clawed feet of the 
 sloth or bear. 
 
 It is obvious, then, that we should be occupied 
 with too limited a view of our subject, were we 
 to consider the human hand in any other light 
 than as presenting the most perfect combination 
 of parts : as exhibiting the bones and muscles 
 which in different animals are suited to parti-
 
 24 FOSSILIZED liONES SHEW 
 
 cular purposes, so combined in the hand, as to 
 perform actions the most minute and compli- 
 cated, consistently with powerful exertion. 
 
 The wonder still is, that whether we examine 
 this system in man, or in any of the inferior 
 species of animals, nothing can be more curiously 
 adjusted or appropriated; and we should be in- 
 clined to say, whatever instance occupied our 
 thoughts for the time, that to this particular 
 object the system had been framed. The view 
 which the subject opens to us, is unbounded. 
 The curious synthesis by which we ascertain 
 the nature, condition, and habits of an extinct 
 animal, from the examination of its fossil re- 
 mains, is grounded on a knowledge of the sys- 
 tem of which we are speaking; and to make 
 the proper use of this department we must 
 understand what a fossil bone is. 
 
 A bone consists of many parts ; but for our 
 present purpose it is only necessary to observe 
 that the hard substance, the phosphate of lime, 
 which we familiarly recognise as bone, is every 
 where penetrated by membranes and vessels as 
 delicate as those which belong to any other part 
 of the body. Fossil bones are those which are 
 found imbedded in the earth, and may be in 
 different conditions. They either retain their 
 animal part, or may have become petrified ; 
 that is to say, the animal matter may have been 
 decomposed and dissipated, with the phosphoric
 
 THE EXTENT OF THE SYSTEM. 25 
 
 acid of the phosphate of lime ; and then, sili- 
 cious earth, or lime in composition with iron, 
 or iron pyrites, may by solution and infiltration 
 fill the interstices of the original earthy matter 
 of the bone ; thus it is converted into stone, and 
 is as permanent as the rock which contains it. 
 It retains the form, though not the internal struc- 
 ture of bone ; and that form, in consequence of 
 the perfect system which we have hinted at, 
 becomes a proof of revolutions the most extra- 
 ordinary. The mind of the enquirer is carried 
 back, not merely to the contemplation of animal 
 structure, but by inference, from the system of 
 animal organization to the structure of the globe 
 itself. 
 
 The remains of marine animals are found in 
 the highest mountains of the old and new world, 
 and great bones are discovered on turning up 
 the surface of our fields; and in the beds of 
 rivers ; and not in the loose soil only, but under 
 the solid limestone rock. The bones thus ex- 
 posed, become naturally a subject of intense 
 interest, and are unexpectedly connected with 
 the enquiry, in which we are engaged. Among 
 other important conclusions they lead to this 
 that there is not only a scheme or system of 
 animal structure pervading all the classes of 
 animals which inhabit the earth, but that the 
 principle of this great plan of creation was in 
 operation, and governed the formation of those
 
 26 ANIMALS THE MOST UNCOUTH 
 
 animals which existed previous to the revolu- 
 tions that the earth itself has undergone : that 
 the excellence of form now seen in the skeleton 
 of man, was in the scheme of animal existence 
 long previous to the formation of man, and 
 before the surface of the earth was prepared 
 for him or suited to his constitution, structure, 
 or capacities. 
 
 A skeleton is dug up which has lain under 
 many fathoms of rock, being the bones of an 
 animal that lived antecedent to that formation 
 of rock, and at a time when the earth's surface 
 must have been in a condition very different 
 from what it is now. These remains prove, that 
 all animals have been formed of the same ele^ 
 ments, and have had analogous organs that 
 they received new matter by digestion, and were 
 nourished by means of a circulating fluid that 
 they possessed feeling through a nervous sys- 
 tem, and were moved by the action of muscles 
 that their organs of digestion, circulation, and 
 respiration were modified by circumstances, as 
 in the animals now alive, and in accordance 
 with their habits and modes of living. The 
 changes in the organs are but variations in the 
 great system by which new matter is assimi- 
 lated to the animal body, and however remark- 
 able these may be, they always bear a certain 
 relation to the original type as parts of the same 
 great design. In examining these bones of the
 
 SUITED TO THEIR CONDITION. 27 
 
 ancient world, so regularly are they formed on 
 the same principle which is evident in the 
 animals now inhabiting the earth, that on ob- 
 serving their shape, and the processes* by 
 which their muscles were attached, we ca'n 
 reduce the animals to which they belonged, to 
 their orders, genera, and species, with as much 
 precision as if the recent bodies had been sub- 
 mitted to the eye of the anatomist. Not only 
 can we demonstrate that their feet were adapted 
 to the solid ground, or to the oozy bed of rivers, 
 for speed, or for grasping and tearing; but 
 judging by these indications of the habits of 
 the animals, we acquire a knowledge of the 
 condition of the earth during their period of 
 existence : that it was suited at one time to the 
 scaly tribe of the lacerta?, with languid motion ; 
 at another, to animals of higher organization, 
 with more varied and lively habits; and finally 
 we learn, that at any period previous to man's 
 creation, the surface of the earth would have 
 been unsuitable to him. 
 
 We ought not to touch on this subject without 
 one observation more. When the peasant sus- 
 pends his work on turning up the great bones of 
 
 * Processes are the projecting parts of bone by which the 
 tendons of the muscles are attached. The processes, therefore, 
 to the anatomist are indications of the conditions of the muscles.
 
 28 ANIMALS THE MOST UNCOUTH 
 
 some unknown animal, and thinks that he has 
 discovered the limbs of a giant, he is more ex- 
 cusable than the learned and ingenious, who 
 desire to illustrate the Scriptures by these natu- 
 ral appearances. True religion is adapted to 
 the sound capacities of every man to that con- 
 dition of mind which the individual experience 
 of the good and evil of the world, sooner or 
 later, brings with it. It is suited to man in every 
 stage of the progress of society to his weak- 
 ness and to his strength, and by which it is 
 the real dispenser of equal rights. Our reli- 
 gion could not have been adapted to every man, 
 had it been framed with a relation to science, 
 and least of all to that branch of natural know- 
 ledge which is called geology a science so 
 obviously in its infancy, that but for the alliance 
 with anatomy, it would continue to present a 
 scene only of confusion for ignorant wonder- 
 ment. It may then be asked why we cultivate 
 those scientific views to which we apply the 
 term natural religion? Because they agreeably 
 enlarge our comprehension, and exalt the ima- 
 gination, while they repress a too selfish enthu- 
 siasm. We all have proceeded a certain length 
 in the examination of natural phenomena, and 
 the convictions arising from the survey are 
 wrought into the opinions of every one. We 
 experience a fresh and cheerful influence when 
 benevolent design is disclosed to us by new 
 facts, or by things familiar presented in a
 
 SUITED TO THEIR CONDITION 7 . 29 
 
 new light: we are sensible of a renewed impulse, 
 a gratification which interferes with no duty. 
 
 We may take this opportunity to correct the 
 notion which some have expressed, of imperfec- 
 tion in the structure of certain animals ; an idea 
 which has sprung from considering them in 
 comparison with ourselves, our structure, and 
 sensibilities, instead of looking on them with 
 reference to their peculiar conditions. 
 
 On comparing some of the present races of 
 animals with the fossil remains of individuals of 
 the same family which are extinct, Buffon has 
 expressed some singular opinions on their im- 
 perfections; and they have, with some reserve, 
 been adopted even by Cuvier. The eloquent 
 Buffon speaks confidently of the unsuitableness 
 of the organs of animals, and the derangement 
 of their instincts. He compares them with the 
 state of human society, where individuals are 
 subject to misery and want. He sympathizes 
 too closely with the bird of prey when he cha- 
 racterises its watchfulness as a lively picture of 
 wretchedness, anxiety, and indigence. If a bird 
 refuses to be domesticated and crammed with 
 meat, it is hardly fair in him to accuse it of 
 gloom and apathy, when the simple fact is that 
 he is treating it in a manner contrary to its 
 natural habits and instincts. The animals I 
 allude to, as more particularly connected with 
 our subject, are of the tardigrade family ; the 
 
 B. E
 
 30 MISTAKEN COMPASSION FOR 
 
 Ai,* in which, as these authorities believe, the 
 defect of organization is the greatest ; and the 
 Unau,f which they consider only a little less 
 miserably provided for existence. 
 
 Modern travellers, in the same manner, ex- 
 press their pity for these animals. Whilst other 
 
 quadrupeds, they say, range in boundless wilds, 
 the sloth hangs suspended by his strong arms, 
 a poor ill -formed creature, deficient as well as 
 deformed, his hind legs too short, and his hair 
 like withered grass; his looks, motions, and 
 cries conspire to excite pity ; and, as if this 
 were not enough, they say that his .moaning 
 makes the tiger relent and turn away. This is 
 not a true picture : the sloth cannot walk, like 
 quadrupeds, but he stretches out his arms, and 
 if he can hook on his claws to the inequalities 
 of the ground, he drags himself along. This is 
 
 * Bradypus Tridactylus: bradypus (slow footed), tridactylus 
 (three (oed), of the order EDENTATA (wanting incisor teeth). 
 t Bradypus didactylus.
 
 ANIMALS OF PECULIAR FORM. 31 
 
 the condition which authorizes such an expres- 
 sion as " the bungled and faulty composition 
 of the sloth." But when he reaches the branch 
 or the rough bark of a tree, his progress is 
 rapid ; he climbs hand over head along the 
 branches till they touch, and thus from bough 
 to bough, and from tree to tree ; he is most 
 alive in the storm, and when the wind blows, 
 and the trees stoop, and the branches wave and 
 meet, he is then upon the march. 
 
 The compassion expressed by these philoso- 
 phers for animals,* which they consider imper- 
 fectly organized, is uncalled for ; as well might 
 they pity the larva of the summer fly, which 
 creeps in the bottom of a pool, because it can- 
 not yet rise upon the wing. As the insect has 
 no impulse to fly until the metamorphosis is 
 perfect, and the wings developed, so we have 
 no reason to suppose that a disposition or in- 
 stinct is given to animals without a corres- 
 ponding provision for motion. The sloth may 
 move tardily on the ground, his long arms and 
 his preposterous claws may be an incumbrance, 
 but they are of advantage in his natural place, 
 among the branches of trees, in obtaining his 
 food, and in giving him shelter and safety from 
 his enemies. 
 
 We must not estimate the slow motions of 
 animals by our own sensations. The motion of 
 the bill of the swallow, or the fly-catcher, in 
 
 * The subject is pursued at the end of the following chapter.
 
 32 MISTAKEN COMPASSION FOR 
 
 catching a fly, is so rapid that we do not see 
 it, but only hear the snap. On the contrary, 
 how very different are the means given to the 
 chamelion for obtaining his food ; he lies more 
 still than the dead leaf, his skin is like the 
 bark of the tree, and takes the hue of sur- 
 rounding objects. Whilst other animals have 
 excitement conforming to their rapid motions, 
 the shrivelled face of the chamelion hardly in- 
 dicates life ; the eyelids are scarcely parted ; 
 he protrudes his tongue with a motion so imper- 
 ceptible towards the insect, that it is touched 
 and caught more certainly than by the most 
 lively action. Thus, various creatures living 
 upon insects reach their prey by different means 
 and instincts ; rapidity of motion, which gives 
 no time for escape, is bestowed on some, while 
 others have a languid and slow movement that 
 excites no alarm. 
 
 The loris, a tardigrade animal, might be 
 pitied too for the slowness of its motions, if they
 
 ANIMALS OF PECULIAR FORM. 33 
 
 were not the very means bestowed upon it as 
 necessary to its existence. It steals on its prey 
 by night, and extends its arm to the bird on the 
 branch, or the great moth, with a motion so 
 imperceptibly slow, as to make sure of its ob- 
 ject.* Just so, the Indian perfectly naked, his 
 hair cut short, and his skin oiled, creeps under 
 the canvass of the tent, and moving like a 
 ghost, stretches out his hand, with a motion so 
 gentle as to displace nothing, and to disturb 
 not even those who are awake and watching. 
 Against such thieves, we are told, that it is 
 hardly possible to guard ; and thus, the neces- 
 sities or vicious desires of man subjugate him, 
 and make him acquire, by practice, the wiliness 
 which is implanted as instinct in brutes; or we 
 may say that in our reason we are brought to 
 imitate the irrational creatures, and so to vindi- 
 cate the necessity for their particular instincts, 
 
 * For our purpose, it may be well to notice other characters 
 of this, and similar animals which prowl by night. They are 
 inhabitants of the tropical regions. Now, the various creatures 
 which enliven the woods in the day-time, in these warm climates, 
 have fine skins, and smooth hair ; but those that seek their prey 
 at night have a thick coat like animals of the arctic regions. 
 What is this but to be clothed as the sentinel is clothed whose 
 watch is in the night ? They have eyes too, which, from their 
 peculiarity, are called nocturnal, being formed to admit a 
 greater pencil of rays of light. For this purpose the globe is 
 large and prominent, and the iris contractile, to open the pupil 
 to the greatest extent. We have seen how all their motions and 
 instincts correspond with their nocturnal habits.
 
 34 FOSSIL ANIMALS SUITED TO 
 
 of which every class affords examples. We have 
 them in insects, as striking as in the loris, or the 
 chamelion. Evelyn describes the actions of the 
 spider (aranea scenica) as exhibiting remarkable 
 cunning in catching a fly. " Did the fly, (he 
 says,) happen not to be within a leap, the spider 
 would move towards it, so softly, that its motion 
 seemed not more perceptible than that of the 
 shadow of the gnomon of a dial." * 
 
 I would only remark further on these motions 
 of the muscles of animals, that we are not to 
 account this slowness a defect, but rather an 
 appropriation of muscular power : since in some 
 animals the same muscles which move their 
 members so as to be hardly perceptible, can at 
 another time act with the velocity of a spring. 
 
 Now Buffon, speaking of the extinct species 
 of the tardigrade family, considers them as 
 monsters by defect of organization : as attempts 
 of nature in which she has failed to perfect her 
 plan : inferring that she has produced animals 
 
 * The passage continues " if the intended prey moved, the 
 spider would keep pace with it exactly as if they were actuated 
 by one spirit, moving backwards, forwards, or on each side with- 
 out turning. When the fly took wing, and pitched itself behind 
 the huntress, she turned round with the swiftness of thought, and 
 always kept her head towards it, though to all appearance as 
 immoveable as one of the nails driven into the wood on which 
 was her station ; till at last, being arrived within due distance, 
 swift as lightning she made the fatal leap, and secured her 
 prey." Evelyn, as quoted by Kirby and Spence.
 
 THE TIME OF THEIR EXISTENCE. 35 
 
 which must have lived miserably, and which are 
 effaced as failures from the list of living beings. 
 The Baron Cuvier does not express himself 
 more favourably when he says of the existing 
 species that they have so little resemblance to 
 the organization of animals generally, and their 
 structure is so much in contrast with that of 
 other creatures, that he could believe them to be 
 the remnants of an order unsuitable to the pre- 
 sent system of nature ; and if we are to look for 
 their congeners, it must be in the interior of the 
 earth, in the ruins of the ancient world. 
 
 The animals of the Antediluvian world were 
 not monsters ; there was no lusus or extrava- 
 gance. Hideous as they appear to us, and like 
 the phantoms of a dream, they were adapted to 
 the condition of the earth when they existed. I 
 could have wished that our naturalists had given 
 the inhabitants of that early condition of the 
 globe, names less scholastic. We have the 
 plesiosaurus, and plesiosaurus dolichodeirus, we
 
 51 i MAN SUITED TO THE PRESENT 
 
 have the ichthyosaurus, megalosaurus, and hylce- 
 osaurus, and iguanodon, pterodactyles, with long 
 and short beaks, tortoises, and crocodiles; and 
 these are found among reeds and grasses of 
 gigantic proportions, algae and fuci, and a great 
 variety of mollusca of inordinate bulk compared 
 with those of the present day, as ammonites and 
 nautili. Every thing declares, that these ani- 
 mals inhabited shallow seas, and estuaries, or 
 great inland lakes : that the surface of the earth 
 did not rise up in peaks and mountains, or that 
 perpendicular rocks bound in the seas ; but that 
 it was flat, slimy, and covered with a loaded and 
 foggy atmosphere. Looking to the class of ani- 
 mals as we have enumerated them, there is a 
 correspondence ; they were scaly ; they swam in 
 water, or crept upon the margins ; there were no 
 animals possessed of rapidity of motion, and no 
 birds of prey to stoop upon them ; there was, in 
 short, that balance of the power of destruction 
 and of self-preservation which we see now to ob- 
 tain in higher animals since created, with infi- 
 nitely varied instincts and means for defence or 
 attack. There is, indeed, every reason to be- 
 lieve that the classes mammalia and birds were 
 not then created. If man had been placed in 
 this condition of the earth, there must have been 
 around him a state of things unsuited to his con- 
 stitution, and not calculated to call forth his 
 capacities.
 
 CONDITION OF THE EARTH. 37 
 
 It is hardly possible to watch the night and 
 see the break of day in a fine country, without 
 being sensible that our pleasantest perceptions 
 refer to the scenery of nature, and that we have 
 feelings in sympathy with every successive 
 change, from the first streak of light until the 
 whole landscape is displayed in valleys, woods, 
 and sparkling waters; and the changes on the 
 scene are not more rapid than the transitions of 
 the feelings which accompany them. All these 
 sources of enjoyment, the clear atmosphere and 
 the refreshing breezes, are as certainly the result 
 of the several changes which the earth's surface 
 has undergone, as the displaced strata within its 
 crust are demonstrative of these changes. We 
 have every reason to conclude that these revo- 
 lutions, whether they have been slowly accom- 
 plished and progressively, or by sudden, vast 
 and successive convulsions, were necessary to 
 prepare the earth for that condition which should 
 correspond with the faculties to be given to man, 
 and be suited to the full exercise of his reason, 
 as well as to his enjoyment. 
 
 If a man contemplate the common objects 
 around him if he observe the connection be- 
 tween the qualities of things external and the 
 exercise of his senses, between the senses so 
 excited, and the condition of his mind, he will 
 perceive that he is in the centre of a magnifi- 
 cent system, which has been prepared for his
 
 38 THEORY OF THE SUCCESSION OF 
 
 reception by a succession of revolutions affecting 
 the whole globe, and that the strictest relation 
 is established between the intellectual capacities 
 and the material world. 
 
 In the succeeding chapter we shall take a 
 comparative view of the anatomy of the arm, 
 and we shall be led to observe some very extra- 
 ordinary changes in their forms, as we trace the 
 same parts through different genera and species 
 of animals. In doing this, we are naturally 
 called upon to take notice of certain opinions 
 which prevail on the subject. 
 
 We have already hinted, that geologists have 
 discovered, that in the stratified rocks there is 
 proof of a regular succession of formations in 
 the crust of the earth, and that animals of very 
 different structure have been imbedded, and are 
 preserved in them. In the earlier formed strata 
 animals are found which are low, as we choose 
 to express it, in the chain of existence ; in 
 higher strata, oviparous animals of great bulk, 
 and more complex structure, are discovered ; 
 above the strata containing these oviparous rep- 
 tiles, there are found mammalia ; and in the 
 looser and more superficial stratum are the bones 
 of the mastodon, megatherium, rhinoceros, and 
 elephant, &c. We must add that geologists 
 agree that man has been created last of all. 
 
 Upon these facts, a theory is raised, that
 
 ANIMALS FROM SIMPLE TO COMPLEX. 39 
 
 there has been a succession of animals gradually 
 increasing in the perfection of their structure ; 
 that the first impulse of nature was not suf- 
 ficient to the production of the highest and most 
 perfect, and that it was only in her mature 
 efforts that mammalia were produced. We are 
 led to this reflection : that the creation of a 
 living animal, the bestowing of life on a cor- 
 poreal frame, however simple the structure of 
 that body, is of itself an act of creative power so 
 inconceivably great, that we can have no title to 
 presume that any change in the organization, 
 such as the provision of bones and muscles, or 
 the production of new organs of sense, is a 
 higher effort of that power. We have a better 
 guide in exploring the varieties of animated 
 nature, when we acknowledge the manifest de- 
 sign with which all is accomplished ; the adap- 
 tation of the animals, their size, their economy, 
 their organs, and instruments to their condition. 
 Whether we make the most superficial or 
 most profound examination of animals in their 
 natural state, we shall find that the varieties 
 are so balanced as to ensure the existence of 
 all. This, we think, goes far to explain, first, 
 why the remains of certain animals are found 
 in certain strata, which indicate a peculiar con- 
 dition of the earth's surface ; and, secondly, 
 why these animals are found grouped together. 
 For, as we may express it, if there had been
 
 40 OF THE SUCCESSION AND 
 
 an error in the grouping, there must have been a 
 destruction of the whole ; the balance necessary 
 to their existence having been destroyed. We 
 know very well that so minute a thing as a fly 
 will produce millions, which, if not checked, 
 will ere long darken the air and render whole 
 regions desolate : so that if the breeze does 
 not carry them in due time into the desert 
 or into the ocean, the destruction will be most 
 fearful. 
 
 As in the present day every creature has its 
 natural enemy ; or is checked in production, 
 sometimes by a limited supply of food, some- 
 times by disease, or by the influence of seasons ; 
 and as in the whole a balance is preserved, we 
 may reasonably apply the same principle in 
 explanation of the condition of things as they 
 existed in the earlier stages of the world's pro- 
 gress ; certainly, this view is borne out, by what 
 we have as yet discovered in the grouping of 
 animals, in the different stratifications or depo- 
 sits of the earth. 
 
 If the Naturalist or Geologist, exploring the 
 rocks of secondary formation, should find ani- 
 mals of the class Mollusca inclosed within them, 
 it agrees with his preconceived notions, that 
 only animals of their simple structure were in 
 existence at the time of the subsidence of that 
 matter of which the rock consists. But if the 
 spine of a fish, or a jawbone, or a tooth, be
 
 GROUPING OF ANIMALS. 41 
 
 discovered, he is much disturbed ; because, here 
 is the indication of an animal having been at 
 that time formed on a different type, on that 
 plan which belongs to animals of a superior 
 class. Whereas on the supposition that animals 
 are created with that relation to circumstances 
 which we have just alluded to, it would only 
 imply that certain animals, which had hitherto 
 increased undisturbed, had arrived at a period 
 when their numbers were to be limited ; or that 
 the condition of the elements, and the abundance 
 of food were now suited to the existence of a 
 species of the vertebrata. 
 
 The principle then, in the application of 
 which we shall be borne out, is, that there is an 
 adaptation, an established and universal relation 
 between the instincts, organization, and instru- 
 ments of animals, on the one hand, and the 
 element in which they are to live, the position 
 which they are to hold, and their means of 
 obtaining food, on the other; and this holds 
 good with respect to the animals which have 
 existed, as well as those which now exist. 
 
 In discussing the subject of the progressive 
 improvement of organized beings, it is affirmed 
 that the last created of all, man, is not superior 
 in organization to the others, and that if de- 
 prived of intellectual power, he is inferior to the 
 brutes. I am not arguing to support the theory 
 of the gradual developement and improvement
 
 42 OF THE SUCCESSION AND 
 
 of organization; but, however indifferent to the 
 tendency of the argument, I must not admit the 
 statement. Man is superior in organization to 
 the brutes, superior in strength in that consti- 
 tutional property which enables him to fulfil his 
 destinies by extending his race in every climate, 
 and living on every variety of nutriment. On 
 the other hand, gather together the most power- 
 ful brutes, from the arctic circle or torrid zone, 
 to some central point so ill suited is their 
 constitution to the change, that they will die ; 
 diseases will be generated, and will destroy 
 them. With respect to the superiority of man 
 being in his mind, and not merely in the provi- 
 sions of his body, it is no doubt true ; but as we 
 proceed, we shall find how the Hand supplies 
 all instruments, and by its correspondence with 
 the intellect gives him universal dominion. It 
 presents the last and best proof of that prin- 
 ciple of adaptation which evinces design in the 
 creation. 
 
 Another notion which we meet with, is, that 
 the variety of animals is not a proof of design, 
 as showing a relation between the formation of 
 their organs and the necessity for their exer- 
 cise; but that the circumstances in which the 
 animal have been placed are the cause of the 
 variety. The influence of these circumstances, 
 it is pretended, has in the long progress of time, 
 produced a complication of structure out of an
 
 GROUPING OF ANIMALS. 43 
 
 animal which was at first simple. We shall re- 
 serve the discussion of this subject until we have 
 the data before us ; which, of themselves, and 
 without much argument, will suffice to over- 
 throw it. 
 
 I may notice here another idea of naturalists, 
 who are pleased to reduce these differences in 
 the structure of animals into general laws. They 
 affirm that in the centre of the animal body 
 there is no disposition to change, whilst in the 
 extremities we see surprising variations of form. 
 If this be a law, there is no more to be said 
 about it, the enquiry is terminated. But I con- 
 tend that the term is quite inapplicable, and 
 worse than useless, as tending to check enquiry. 
 What then is the meaning of this variation in 
 the form of the extremities and the comparative 
 permanence towards the centre of the skeleton ? 
 I conceive the rationale to be this, that the cen- 
 tral parts, by which in fact they mean the skull, 
 spine, and ribs, are permanent in their offices ; 
 whilst the extremities vary and are adapted to 
 every exterior circumstance. The office of the 
 back part of the skull is to protect the brain, 
 that of the spine to contain the spinal marrow, 
 and of the ribs to perform respiration. Why 
 should we expect these parts to vary in shape 
 while their office remains the same? But the 
 shoulder must vary in form, as it does in motion. 
 The shape of the bones and the joints of the
 
 44 SUCCESSION AND GROUPING OF ANIMALS. 
 
 extremities must be adapted to their various 
 actions, and the carpus, or the tarsus, and pha- 
 langes* must change, more than all the rest, 
 to accommodate the extremity to its different 
 offices. Is it not more pleasing to see the reason 
 of this most surprising adjustment, than merely 
 to say it is a law ? t 
 
 There is yet another opinion, which will sug- 
 gest itself by the perusal of the following chap- 
 ter, to those who have read the more modern 
 works on Natural History. It is supposed that 
 the same elementary parts belong to all animals, 
 and that the varieties of structure are attri- 
 butable to the transposition of these elementary 
 parts. I find it utterly impossible to follow up 
 this system to the extent which its abettors 
 would persuade us to be practicable. I object 
 to it as a means of engaging us in very trifling 
 pursuits and of diverting the mind from the 
 truth ; from that conclusion, indeed, to which I 
 may avow it to be my intention to carry the 
 reader. But this discussion also must follow the 
 examples, and we shall resume it in a latter part 
 of the volume. 
 
 * Carpus, the wrist; tarsus, the ankle or instep; phalanges, 
 the rows of bones forming the fingers or toes, 
 f See the Additional Illustrations.
 
 CHAPTER III. 
 
 Tilt Comparative Anatomy of the Hand. 
 
 IN this enquiry, we have before us what in the 
 strictest sense of the word is a system. All the 
 individuals of the extensive division of the ani- 
 mal kingdom which we have to review, possess a 
 cranium for the protection of the brain, a heart, 
 implying a peculiar circulation, five distin- 
 guishable organs of sense ; but the grand pecu- 
 liarity, whence the term vertebrata is derived, is 
 to be found in the spine ; that chain of bones 
 which connects the head and body, and, like a 
 keel, serves as a foundation for the ribs, or as 
 the basis of that fabric which is for respiration. 
 
 I have said, that we are to confine ourselves 
 to a portion only of this combined structure ; to 
 separate and examine the anterior extremity, 
 and to observe the adaptation of its parts, 
 through the whole range of these animals. We
 
 46 COMPARATIVE ANATOMY 
 
 shall view it as it exists in man, and in the 
 higher division of animals which give suck, the 
 mammalia in those which propagate by eggs, 
 the oviparous animals, birds, reptiles, amphi- 
 bia, and fishes ; and we shall find the bones 
 which are identified by certain common fea- 
 tures, adjusted to various purposes, in all the 
 series from the arm to the fin. We shall recog- 
 nise them in the mole, formed into a powerful 
 apparatus for digging, by which the animal soon 
 covers itself, and burrows its way under ground. 
 In the wing of the eagle we shall count every 
 bone, and find that they are adapted to a new 
 element, as powerful to rise in the air, as the fin 
 of the salmon is to strike through the water. 
 The solid hoof of the horse, the cleft foot of the 
 ruminant, the paw with retractile claws of the 
 feline tribe, the long folding nails of the sloth, 
 are among the many changes that are found in 
 the adjustment of the chain of bones, which in 
 man, ministers to the compound motions of the 
 hand. 
 
 Were it my purpose to teach the elements of 
 this subject, I should commence by examining 
 the lowest animals, and trace the bones of the 
 anterior extremity as they come to resemble the 
 human arm, and to be employed for a greater 
 variety of uses in the higher animals; but as my 
 present object is illustration only, I shall begin 
 with the human hand, and compare its parts.
 
 OF THE SHOULDER. 47 
 
 With this view, I shall divide the extremity into 
 the shoulder, arm, and hand, and treat each 
 subdivision with a reference to its structure in 
 animals. 
 
 OF THE SHOULDER. 
 
 In viewing the human figure, or human skele- 
 ton, in connexion with our present subject, we
 
 48 COMPARATIVE ANATOMY 
 
 remark the strength and solidity of the lower 
 extremities, in contrast with the superior. Not 
 only are the lower limbs longer and larger than 
 those of any other animal, but the pelvis is 
 wider, and the obliquity of the neck of the thigh 
 bone greater. The distances of the large pro- 
 cesses on the upper ends of the thigh bones (the 
 trochanters,) from the sockets, are also greater 
 than in any of the vertebrata. Altogether the 
 strength of these bones, the size and prominence 
 of their processes, the great mass of the muscles 
 of the loins and hips, distinguish man from 
 every other animal ; they secure to him the up- 
 right posture, and give him the perfect freedom 
 of the arms, for purposes of ingenuity and art. 
 
 At the head of this chapter is a sketch of the 
 Chimpanzee,* an ape which stands high in the 
 order of quadrumana ; yet we cannot mistake 
 
 * Simia troglodytes, from the coast of Guinea, more human 
 in its form, and more easily domesticated than the ourang-outang. 
 We would do well to consider the abode of these creatures in a 
 state of nature vast forests, extending in impenetrable shade 
 below, whilst above, and exposed to the light, there is a scene 
 of verdure and beauty ; this is the home of those monkeys and 
 lemurs which have extremities like hands. In many of them the 
 hinder extremity has the more perfect resemblance to a hand ; 
 and in the Coaita (p. 19) we see the great toe assuming the cha- 
 racters of a thumb, whilst in the fore paw the thumb is not dis- 
 tinguishable, being hid in the skin. In short, these paws are not 
 approximations to the hand, corresponding with a higher inge- 
 nuity, but are adaptations of the feet to the branches on which 
 the animals climb and walk.
 
 OF THE SHOULDER. 49 
 
 his capacities: that the lower extremities and 
 pelvis, or hips, were never intended to give him 
 the erect posture, or only for a moment; but for 
 swinging, or for a vigorous pull, who can deny 
 him power in those long and sinewy arms. 
 
 The full prominent shoulders, and the conse- 
 quent squareness of the trunk, are equally dis- 
 tinctive of man with the strength of his loins; 
 they indicate a free motion of the hand. 
 
 OF THE BONES OF THE SHOULDER. 
 
 The bones of the shoulder, being those which 
 give firm attachment to the upper extremity, 
 and which afford origins to the muscles of the 
 arm and fore arm, are simple, if studied in man, 
 or, indeed, in any one genus of animals ; but 
 considered in reference to the whole of the 
 vertebral animals, they assume a very extraor- 
 dinary degree of intricacy. We shall, however, 
 find that they retain their proper office, notwith- 
 standing the strange variations in the form of 
 the neighbouring parts. In man they are di- 
 rectly connected with the great apparatus of 
 respiration ; but in other animals we shall see 
 the ribs, as it were, withdrawn, and the bones of 
 the shoulder, or fundamental bones of the extre- 
 mity, curiously and mechanically adapted to 
 perform their office without the support of the 
 thorax. We shall not, however, anticipate the 
 difficulties of this subject, but look first upon
 
 50 COMPARATIVE ANATOMY 
 
 that which is most familiar and easy, the shoul- 
 der of man in comparison with the varieties in 
 the mammalia. 
 
 OF THE CLAVICLE. 
 
 The clavicle, or collar bone, is that which runs 
 across from the breast bone to the top of the 
 shoulder. The square form of the chest, and 
 the free exercise of the hand, are very much 
 owing to this bone. It keeps the shoulders 
 apart from the chest, and throws the action of 
 the muscles proceeding from the ribs upon the 
 arm bone, which, but for it, would be drawn in- 
 wards, and contract the upper part of the trunk. 
 
 If we take the motions of the anterior extre- 
 mity in different animals as our guide, we shall 
 see why this bone is perfect in some, and 
 entirely wanting in others. Animals which fly, 
 
 A. Triangular portion of the Sternum, or breastbone. B. B. 
 Clavicles, or collar bones, c. c. Scapulae, or shoulder blades. 
 D. Coracoid process of the Scapulae. E. Acromion process of 
 the Scapulae, forming the tip of the shoulder.
 
 OF THE SHOULDER. 51 
 
 or dig, or climb, as bats, moles, porcupines, 
 squirrels, ant-eaters, armadilloes, and sloths, 
 have this bone, for in them, a lateral or outward 
 motion is required. There is also a certain de- 
 gree of freedom in the anterior extremity of the 
 cat, dog, martin, and bear; they strike with the 
 paw, and rotate the wrist more or less exten- 
 sively, and they have therefore a clavicle, 
 though an imperfect one. In some of these, 
 even in the lion, the bone which has the place 
 of the clavicle is very imperfect indeed; and if 
 attached to the shoulder, it does not extend to 
 the sternum : it is concealed in the flesh, and is 
 like the mere rudiments of the bone. But, how- 
 ever imperfect, it marks a correspondence in the 
 bones of the shoulder to those of the arm and 
 paw, and the extent of motion enjoyed. 
 
 When the bear stands up, we perceive, by his 
 ungainly attitude and the motion of his paws,
 
 52 COMPARATIVE ANATOMY 
 
 that there must be a wide difference in the 
 bones of his upper extremity, from those of the 
 ruminant or solipede. He can take the keepers 
 hat from his head, and hold it; he can hug an 
 animal to death. The ant-bear especially, as 
 he is deficient in teeth, possesses extraordinary 
 powers of hugging with his great paws ; and, al- 
 though harmless in disposition, he can squeeze 
 his enemy, the jaguar, to death. These actions, 
 and the power of climbing, result from the struc- 
 ture of the shoulder, or from possessing a collar 
 bone, however imperfect. 
 
 Although the clavicle is perfect in man, there- 
 by corresponding with the extent and freedom 
 of the motion of his hand, it is strongest and 
 longest, comparatively, in the animals which dig 
 or fly, as in the mole and the bat. 
 
 Preposterous as the forms of the kangaroo 
 appear to us, yet even in this animal we see a 
 relation preserved between the extremities. He 
 sits upon his strong hind legs and tail, tripod 
 like, with perfect security, and his fore paws are 
 free. He has a clavicle, and possessing that 
 bone and the corresponding motions, is not with- 
 out means of defence ; for with the anterior ex- 
 tremities he seizes the most powerful dog, and 
 then, drawing up his hinder feet, he digs his 
 sharp pointed hoofs into his enemy, and striking 
 out, tears him to pieces. Though possessed of no 
 great speed, and without horns, teeth, or claws,
 
 OF THE SHOULDER. 53 
 
 and, as we should suppose, totally defenceless, 
 nature has not been negligent of his protection.* 
 It cannot be better shown, that the function 
 or use of a part, determines its form, than by 
 looking to the clavicle and scapula of the bird. 
 
 Three bones converge here to the shoulder 
 joint, the furculum, clavicle, and scapula; but 
 
 * There is in the form of the kangaroo, and especially in its 
 skeleton, something incongruous, and in contrast with the usual 
 shape of quadrupeds. The head, trunk, and fore paws, appear 
 to be a portion of an animal unnaturally joined to another of 
 greater dimensions and strength. It is not easy to say what are, 
 or what were, the exterior relations corresponding with the very 
 
 B. H
 
 54 COMPARATIVE STRUCTURE OF 
 
 none of these have the resemblance which their 
 names would imply. The scapula is the long 
 thin bone, like the blade of a knife ; and the 
 clavicle is that stronger portion of bone which is 
 articulated with the breast bone ; this leaves the 
 furculum as a new part. Now I think that the 
 furculum, or fork bone, which, in carving, we 
 detach after removing the wings of a fowl, cor- 
 responds with the form and place of the clavicle ; 
 and if we so consider it, we may then take the 
 strong bone commonly called the clavicle, as a 
 process of the irregularly formed scapula. How- 
 ever this may be, what we have to admire in 
 birds, is the mode in which the bones are 
 fashioned to strengthen the articulation of the 
 shoulder, and to give extent of surface for the 
 attachment of the muscles which move the 
 wings. 
 
 Another peculiarity in birds is, that there is 
 not an alternate motion of the wings ; their ex- 
 tremities, as we may continue to call them, move 
 together in flying ; and, therefore it is that the 
 clavicles are joined to form the furculum. 
 
 peculiar form of this animal ; but the interior anatomy is accom- 
 modated, in a most remarkable manner, to the enormous hinder 
 extremities. The subject is taken up in the " Additional Illus- 
 trations" in the latter part of the volume, ON THE GENERAL 
 
 FOHM OF THE SKELETON.
 
 THE BONES OF THE SHOULDER. 55 
 
 OF THE SCAPULA. 
 
 IF we attend to the scapula, or shoulder-blade, 
 we shall better understand the influence of the 
 bones of the shoulder on the motions and speed 
 of animals. The scapula is that flat triangular 
 bone (see page 47), which lies on the ribs, and 
 is cushioned with muscles. On its anterior angle 
 there is a depressed surface, the glenoid cavity 
 or socket for the arm bone. The scapula shifts 
 and revolves with each movement of the arm. 
 The muscles converge from all sides towards it, 
 from the head, spine, ribs, and breast bone. 
 These acting in succession, roll the scapula and 
 toss the arm, in every direction. When the 
 muscles combine in action, they fix the bone, 
 and either raise the ribs in drawing breath, or 
 give firmness to the whole frame of the trunk. 
 
 Before I remark further on the influence of 
 the scapulae on the motions of the arms, I shall 
 give an instance in proof of a very important 
 function which they perform. Hearing that 
 there was a poor lad of fourteen years of age, 
 born without arms, and whose unhappy condi- 
 tion had excited the benevolence of some ladies, 
 I sent for him. I found that indeed he had no 
 arms, but he had clavicles and scapulae. When 
 I made this boy draw his breath, the shoulders 
 were raised, that is to say, the scapulae were 
 drawn up, were fixed, and became the points
 
 50 ANATOMY OF THE 
 
 from which the broad muscles of the chest di- 
 verged towards the ribs, to draw and expand 
 them in respiration. We would do well to re- 
 member this double office of the scapula and its 
 muscles, that, whilst they are the very foundation 
 of the bones of the upper extremity, and never 
 wanting in any animal that has the most remote 
 resemblance to an arm, it is the centre and point 
 d'appui of the muscles of respiration, and acts, 
 in that capacity, where there are no extremities 
 at all!* 
 
 We perceive that it is only in certain classes 
 of animals, that the scapula is joined to the 
 trunk by bone, that is, through the medium of a 
 clavicle ; and a slight depression on a process of 
 the scapula, when discovered in a fossil state, 
 will therefore declare to the geologist the class to 
 which the animal belonged. For example, there 
 are brought over to this country the bones of the 
 Megatherium, an animal which must have been 
 larger than the elephant ; of the anterior extre- 
 mity there is only the scapula ; and on the end 
 of the process, called acromion, of that bone, 
 there is a mark of the attachment of a clavicle. 
 This points out the whole constitution of the 
 extremity, and that it enjoyed perfect freedom 
 of motion. Other circumstances will declare 
 
 * Some curious facts illustrative of this office of the muscles of 
 the arm situated on the chest are stated in the author's paper on 
 the VOICE, in the Philosophical Transactions. 1832.
 
 HORSE'S SHOULDER. 57 
 
 whether that extensive motion was bestowed so 
 that the animal might dig with its huge claws 
 like some of the edentata, or strike like the 
 feline tribe. 
 
 Some interest is attached to the position of 
 the scapula, in the horse. In him, and in other 
 quadrupeds, with the exceptions which I have 
 made, there is no clavicle, and the connection 
 between the extremity and the trunk is solely 
 through muscles. That muscle called serratus 
 magnus. which is a large one in man, is parti- 
 cularly powerful in the horse ; for the weight 
 of the trunk hangs upon this muscle. In the 
 horse, as in most quadrupeds, the speed results 
 from the strength of the loins and hinder extre- 
 mities ; for it is the muscles there which propel 
 the animal. But were the anterior extremities 
 joined to the trunk firmly, and by bone, they 
 could not withstand the shock from the descent 
 of the whole weight thrown forwards ; even 
 though they were as powerful as the posterior 
 extremities, they would suffer fracture or dislo- 
 cation. We cannot but admire, therefore, the 
 provision in all quadrupeds whose speed is great, 
 and whose spring is extensive, that, from the 
 relative position of their bones, they have an 
 elastic resistance, by which the shock of descend- 
 ing is diminished.
 
 58 
 
 ANATOMY OF THE 
 
 If we observe the bones of the anterior extre- 
 mity of the horse, we shall see that the scapula 
 is oblique to the chest ; the humerus oblique to 
 the scapula ; and the bones of the fore arm at 
 an angle with the humerus. Were these bones 
 connected together in a straight line, end to end, 
 the shock of alighting would be conveyed as 
 through a solid column, and the bones of the 
 foot, or the joints, would suffer from the con- 
 cussion. When the rider is thrown forwards on 
 his hands, and more certainly when he is 
 pitched on his shoulder, the collar bone is broken, 
 because in man, this bone forms a link of con- 
 nection between the shoulder and the trunk, so
 
 HORSE'S SHOULDER. 50 
 
 as to receive the whole shock; and the same 
 would happen in the horse, the stag, and all 
 quadrupeds of great strength and swiftness, were 
 not the scapulae sustained by muscles, and not 
 by bone, and did not the bones recoil and fold up. 
 
 The horse-jockey runs his hand down the 
 horse's neck, in a knowing way, and says, "this 
 horse has got a heavy shoulder, he is a slow 
 horse ! " He is right, but he does not under- 
 stand the matter ; it is not possible that the 
 shoulder can be too much loaded with muscle, 
 for muscle is the source of motion, and bestows 
 power. What the jockey feels, and forms his 
 judgment on, is the abrupt transition from the 
 neck to the shoulder, which, in a horse for the 
 turf, ought to be a smooth undulating surface. 
 This abruptness, or prominence of the shoulder, 
 is a consequence of the upright position of the 
 scapula ; the sloping and light shoulder results 
 from its obliquity. An upright shoulder is the 
 mark of a stumbling horse : it does not revolve 
 easily, to throw forward the foot. 
 
 Much of the strength, if not the freedom and 
 rapidity of motion, of a limb, will depend on the 
 angle at which the bones lie to each other; for, 
 this mainly affects the insertion, and, conse- 
 quently, the power of the muscles. We know, 
 and may every moment feel, that when the arm 
 is extended, we possess little power in bending 
 it ; but as we bend it the power is increased ;
 
 
 
 COMPARISON OF THE BONES 
 
 which is owing to the change in the direction of 
 the force acting upon the bone ; or, in other 
 words, because the tendon becomes more per- 
 pendicular to the lever. A scapula which in- 
 
 clines obliquely backwards, increases the angle 
 at which it lies with the humerus, or arm bone, 
 and, consequently, improves the effect of those 
 muscles which pass from it to that bone. We 
 have only to turn to the skeleton of the elephant, 
 
 A. Scapula. E. Humerus, or arm-bone. B. Tuberosity of the 
 Humerus. c. Olecranou, or projection of the Ulna. D. Radius.
 
 OF THE HORSE'S SHOULDER. 61 
 
 the ox, the elk, or the stag, to see the confirma- 
 tion of this principle. When the scapula is 
 oblique, the serratus muscle, which passes from 
 the ribs to its uppermost part, has more power 
 in rolling it. When it lies at right angles with 
 the humerus, the muscles which are attached to 
 the latter, (at B.) act with more effect. And on 
 the same principle, by the oblique position of 
 the humerus, and, consequently, its obliquity in 
 reference to the radius and ulna, the two bones 
 of the fore-arm, the power of the muscle in- 
 serted (at C.) into the olecranon, is increased. 
 On the whole, both power and elasticity are 
 gained by this position of the superior bones of 
 the fore-leg. It gives to the animal that springs, 
 a larger stretch in throwing himself forwards, 
 and security, in a soft descent of his weight. A 
 man, standing upright, cannot leap or start oft* 
 at once ; he must first sink down, and bring the 
 bones of his extremities to an angle. But the 
 antelope, or other timid animals of the class, can 
 leap at once, or start off in their course without 
 preparation : another advantage of the oblique 
 position of their bones when at rest. 
 
 These sketches with the pen are from the 
 skeletons of the elephant and the camel. The 
 leg of the former is obviously built for the 
 purpose of sustaining the huge bulk of the 
 animal, whilst in the camel we have a perfect 
 contrast.
 
 COMPARISON OF THE BONES
 
 OF THE ELEPHANT AND CAMEL. 63 
 
 Were we to compare the bones of these larger 
 animals with any form of architecture, it would 
 be with the Egyptian, or rather they are like the 
 Cyclopean walls of some ancient city ; they are 
 huge and shapeless, and piled over each other, 
 as if they were destined more to sustain weight, 
 than to permit motion. 
 
 We further perceive, from the comparison of 
 these sketches, that if the humerus be placed 
 obliquely, it must necessarily be short, otherwise 
 it would throw the leg too far back, and make 
 the head and neck project. It is one of the 
 " points" of a horse to have the humerus short. 
 And not only have all animals of speed this cha- 
 racter, but birds of long flight, as the swallow, 
 have short humeri. This is owing, I think, to 
 another circumstance, that in the wing, the short 
 humerus causes a quicker extension ; for the 
 further extremity of the bone moving in a lesser 
 circle, makes the gyration be more rapid. 
 
 If we take the bones of the shoulder as a 
 distinct subject, and trace them comparatively, 
 we shall be led to notice some very curious 
 modifications in them. We have already seen 
 that there are two objects to be attained in the 
 construction of these bones. In man, and mam- 
 malia, they constitute an important part of the 
 organ of respiration; and they conform to the 
 structure of the thorax. But we shall find that
 
 64 BONES OF THE SHOULDER 
 
 in some animals, this function is in a manner 
 withdrawn from them ; the scapulae and the 
 clavicles are left without the support of the ribs. 
 These bones forming the shoulder, therefore, 
 require additional carpentry; or they must be 
 laid together on a new principle. In the batra- 
 chian order,* for example in the frog, the thorax, 
 as constituted of ribs, has disappeared ; the 
 mechanism of respiration is altogether different 
 from what it is in the mammalia. Accordingly, 
 we find that the bones of the shoulder are on a 
 new model ; they form a broad and flat circle,t 
 
 sufficient to give secure attachment to the extre- 
 mity, and affording a large space for the lodge- 
 ment of the muscles which move the arm. Per- 
 haps the best example of this structure is in the 
 
 * See the Appendix under the 3rd Class of Vertebrata, 
 Reptiles. 
 
 t The Scapula, Clavicle, Sternum, and Coracoid bone may 
 be recognised in this figure of the bones of a Frog.
 
 IN THE CHELONIAN ORDER. 65 
 
 siren and proteus ; where the ribs are reduced to 
 a very few imperfect processes, attached to the 
 anterior dorsal vertebrae ; and where the bones 
 of the shoulder, being deprived of all support 
 from the thorax, depend upon themselves for 
 security. Here the bones corresponding to the 
 sternum, clavicles, and scapulae, are found cling- 
 
 /* 
 
 ing to the spine, and forming, like the pelvis,* 
 a circle, to the lateral part of which the humerus 
 or arm bone is articulated. 
 
 In the chelonian order, -f the tortoises, we see 
 another design accomplished, in the union of 
 these bones ; and the change is owing to a very 
 curious circumstance. The spine and ribs of 
 
 * The pelvis is the circle of bones on which the spine or back- 
 bone rests, and in which are the sockets for the heads of the 
 thigh bones. 
 
 t See again the Appendix, iii. Class of Vertebrata.
 
 (JO COMPARATIVE ANATOMY 
 
 these animals are like rafters placed under the 
 strong shell which covers them, and being united 
 to the shell they are consequently external to the 
 bones of the shoulder. The scapulae and clavi- 
 cles being thus within the thorax, and having 
 nothing in their grasp, neither ribs nor spine, 
 they must necessarily fall together, and form a 
 circle, in order to afford fixed points to which the 
 extremities may be attached. It would, indeed, 
 be strange if now being joined for the purpose 
 of giving attachment to the humerus, and in cir- 
 cumstances, as we may express it, so very new, 
 they preserved any resemblance to the forms 
 which we have been contemplating in the higher 
 
 animals. In this figure,* we have the bones of 
 
 * A. Scapula. B. Acromion process, c. Coracoid bone. 
 D. Glenoid cavity.
 
 IN THE CHELONIAN ORDER. 67 
 
 the shoulder of the turtle ; and it is readily per- 
 ceived how much they have changed both their 
 shape and their offices. That part which is 
 most like a scapula in shape, lies on the fore 
 part instead of the back part; and the bones 
 which hold' the shoulders apart, abut upon the 
 spine, instead of upon the sternum. Hence it 
 appears idle to follow out these bones under 
 the old denominations, or such as are applicable 
 to their condition in the higher animals. 
 
 In fishes, where the apparatus of respiration 
 has undergone another entire change, and where 
 there are no proper ribs, the bones which give 
 attachment to the pectoral fin, are still called 
 the bones of the shoulder; and that which is 
 named scapular appendage, is, in fact, attached 
 to the bones of the head, instead of to the ribs 
 or spine. So that the whole consists of a 
 circle of bones, which, we may say, seek se- 
 curity of attachment by approaching the more 
 solid part of the head, in defect of a firm foun- 
 dation in the thorax. 
 
 Thus the bones which form the shoulder joint, 
 and, in a manner, give a foundation to the an- 
 terior extremity, have been submitted to a new 
 modelling in correspondence with every variety 
 in the apparatus of respiration ; and they have 
 yet maintained their pristine office. 
 
 The naturalist will not be surprised on finding 
 an extraordinary intricacy in the shoulder ap-
 
 08 COMPARATIVE ANATOMY 
 
 paratus of the ornithorynchus paradoxus, since 
 the whole frame and organs of this animal 
 imply that it is intermediate between mammalia 
 and birds ; it is placed in the list of edentata. 
 It affords us another instance of the changes 
 which the bones of the shoulder undergo with 
 every new office, and in correspondence with 
 the motions of the extremity ; whether it be to 
 support the weight in running, or to give free- 
 dom to the arm, or to provide for flying, or for 
 performing equally the acts of creeping and of 
 swimming. 
 
 Unprofitable as the enquiry may seem, there 
 is no other way by which the geologist can dis- 
 tinguish the genera of those extinct and strange- 
 ly formed oviparous reptiles which he finds 
 imbedded in the secondary strata, than by stu- 
 dying the minute processes and varying charac- 
 ters of these bones, in the recent species. In 
 the ichthyosaurus, and plesiosaurus, the inha- 
 bitants of a former world, we perceive a consi- 
 derable deviation from the perfection of the 
 bones of the arm and hand, compared with the 
 frog and tortoise. But if strength be the ob- 
 ject, there is a greater degree of perfection in 
 the bones of the shoulder, in these extinct rep- 
 tiles. The explanation of this is, that the ribs 
 and sterno-costal arches, constituting the thorax, 
 are more perfect than in the chelonian and ba- 
 trachian orders; and the bones of the shoulder
 
 OF THE BONES OF THE SHOULDER. 69 
 
 are therefore external, and resemble those of the 
 crocodile ; yet the ribs are so weak as to be in- 
 capable of sustaining the powerful action of the 
 muscles of the anterior extremities, or paddles ; 
 accordingly, the bones, which by a kind of 
 license we continue to call clavicle, omoplate or 
 scapula, and coracoid, though strangely devi- 
 ating from the original form and connections, 
 constitute a texture of considerable strength, 
 which perfects the anterior part of the trunk, 
 and gives attachment and lodgement to the 
 powerful muscles of the paddle. 
 
 But in giving their attention to this subject, 
 it does not appear that naturalists have hit upon 
 the right explanation of the. peculiar structure, 
 and curious varieties of these bones r in the class 
 of reptiles. Why is the apparatus of respiration 
 so totally changed in these animals? They are 
 cold blooded animals; they require to respire 
 less frequently than other creatures, and they 
 remain long under the water. I conceive that 
 the peculiarity in their mode of respiration cor- 
 responds with this property. Hence their ve- 
 sicular lungs, their mode of swallowing the air, 
 instead of inhaling it ; and hence, especially, 
 their power of compressing the body and ex- 
 pelling the air. It is this provision for emptying 
 the lungs, I imagine, which enables them to go 
 under the water and crawl upon the bottom; 
 without it, that is to say, had they possessed the 
 
 B. I
 
 70 COMPARATIVE ANATOMY 
 
 lungs of warm blooded animals, which are com- 
 pressible only in a slight degree, their capacity 
 of remaining under water would have left them 
 struggling against their buoyancy, like a man, 
 or any of the mammalia, when diving. The 
 girdle of bones of the shoulder is constituted 
 with a certain regard to the peculiar action of 
 respiration, and to the pliancy of the body, in 
 order that the vesicular lungs may be com- 
 pressed, and the specific weight diminished. 
 The facility which the absence of ribs gives, in 
 the batrachian order, for admitting the com- 
 pression of the lungs extended through the ab- 
 domen, and the extreme weakness and pliancy 
 of the bones in the saurians, must be, as I ap- 
 prehend, peculiarities adapted to the same end. 
 
 OF THE HUMERUS, OR ARM BONE. 
 
 The demonstration of this bone need not 
 be so dry a matter of detail as the anatomist 
 makes it. We may see in its form that curious 
 relation of parts which has been so successfully 
 employed by Paley to prove design, and from 
 which the genius of Baron Cuvier has brought 
 out some of the finest examples of inductive 
 reasoning. 
 
 In looking to the head of this bone in the 
 human skeleton, (see the fig. page 47,) we 
 observe the great hemispherical surface for arti- 
 culation with the glenoid cavity or socket of the 
 scapula, and we see that the two tubercles for
 
 OF THE HUMERUS. 71 
 
 the insertion of the muscles, near the joint, are 
 depressed, and do not interfere with the re- 
 volving of the humerus, by striking against the 
 edges of the socket. Such appearances alone 
 are sufficient to show that all the motions of the 
 arm are free. 
 
 To give assurance of 
 this, and to illustrate how 
 the form of the shoulder 
 points to the structure of 
 the whole arm, suppose 
 that the geologist has pick- 
 ed up this bone in inter- 
 esting circumstances. To 
 what animal does it be- 
 long? The circular form 
 of the articulating surface, and the very slight 
 projection of the tubercles, evince a latitude and 
 extent of motion. Now, freedom of motion in 
 the shoulder implies freedom also in the extre- 
 mity or paw, and rotation of the bones of the 
 wrist. Accordingly, we direct the eye to that 
 part of this humerus which gives origin to the 
 muscles for turning the wrist, (the Supinator 
 muscles)-, and in the prominence and length of 
 the ridge or crest which is on the lower and 
 outer side of the bone, we have proof of the 
 strength of these muscles, and consequently of 
 the free motion of the paw. 
 
 Therefore, on finding the humerus thus cha- 
 racterized, we conclude, that it belonged to an
 
 72 COMPARATIVE ANATOMY 
 
 animal with sharp moveable claws ; that, in all 
 probability, it is the remains of a bear. 
 
 But, suppose that the bone found has a dif- 
 ferent character : That the tubercles project, 
 so as to limit the motion to one direction, and 
 that the articulating surface is less regularly 
 convex. On inspecting the lower extremity of 
 
 such a bone, we shall perceive provisions for a 
 deeper and more secure hinge joint at the elbow; 
 and neither in the form of the articulating sur- 
 face, (which is here called trochlea,) nor in the 
 crest or spine on the outside, above noticed, will 
 there be signs of the rotation of one bone of the 
 fore-arm on the other. We have, therefore, got 
 the bone of an herbivorous quadruped, either 
 with a solid or with a cloven foot. 
 
 In the bat and mole we have, perhaps, the 
 best examples of the moulding of the bones of
 
 OF THE HUMEKUS. 73 
 
 the extremity to correspond with the condition 
 of the animal. The mole is an animal fitted to 
 plough its way under ground. In the bat, the 
 same system of bones is adapted to form a wing, 
 to raise the animal in the atmosphere, with a 
 provision for it to cling on the wall, not to bear 
 upon. We recognise in both of these animals 
 every bone of the upper extremity ; but how 
 very differently formed and joined ! In the 
 mole, the sternum or breast bone, and the cla- 
 vicle are remarkably large: the scapula, or 
 shoulder blade, assumes the form of a high 
 lever: the humerus is thick and short, and has 
 such prominent spines for the attachment of 
 muscles, as to indicate great power. The spines 
 which give origin to the muscles of rotation, 
 project in an extraordinary manner; and the 
 hand is large, flat, and so turned that it may 
 shove the earth aside like a ploughshare.* 
 
 * The snout may vary in its internal structure with new offices. 
 Naturalists say that there .is a new " element" in the pig's nose. 
 It has, in fart, two bones which admit of motion, whilst they give
 
 74 
 
 COMPARATIVE ANATOMY 
 
 There can be no greater contrast to these 
 bones of the mole than is presented in the 
 skeleton of the bat. In this animal the bones 
 are light and delicate ; and whilst they are all 
 marvellously extended, the phalanges or the 
 rows of bones of the fingers, are elongated so as 
 hardly to be recognised, obviously for the pur- 
 
 more strength in digging the ground. Moles have those bones 
 also, as they plough the earth with their snouts. We have noticed 
 the manner in which they use their strong hands; we should add 
 that their head is like a wedge, to which their hands are assisting 
 in burrowing and throwing aside the earth. The conformation of 
 the head, in shape and strength of bones, and the new adjust- 
 ment of a muscle, which is cutaneous in other animals (the 
 Platisma Myoides) to assist in the motions of the head, are 
 among the most curious changes of common parts to new offices. 
 See again the " Additional Illustrations."
 
 OF THE BAT. 75 
 
 pose of sustaining a membraneous web, and to 
 form a wing. 
 
 Contemplating this extraordinary application 
 of the bones of the upper extremity, and com- 
 paring it with the wing of a bird, we might say, 
 that in the bat, it is an awkward attempt " a 
 failure." But before giving expression to such 
 an opinion, we must understand the objects re- 
 quired in this construction. It is not a wing 
 intended merely for flight that the bat possesses, 
 but one which, while it raises the animal, is 
 capable of receiving a new sensation, or sensa- 
 tions in that exquisite degree so as almost to 
 constitute a new sense. On the fine web of the 
 bat's wing nerves are distributed, which enable 
 it during the obscurity of night, when both eyes 
 and ears fail, to avoid objects in its flight. 
 Could the wing of a bird, covered with feathers, 
 do this? Here then we have another example 
 of the necessity of taking every circumstance 
 into consideration before we presume to cri- 
 ticise the ways of nature. It is a lesson of 
 humility.* 
 
 In the next page we have a sketch of the arm 
 
 * Besides the adaptation of the bat for flight, through a new 
 adjustment of the bones of the arm, this animal has cells under 
 ] ts skin ; but I know not how far I am authorized to say that they 
 are analogous to the air-cells of birds, or that they are for the 
 purpose of making the bat specifically lighter. They extend over 
 the breast, and under the axillae in some bats ; and they are filled 
 by an orifice which communicates with the pharynx.
 
 76 COMPARATIVE ANATOMY 
 
 bones of the Ant-eater,* to shew once more the 
 correspondence that is maintained in the whole 
 extremity. We observe these extraordinary 
 gpiaes of the humerus, indicating the power of 
 the muscles which are at- 
 tached to it ; for, as I have 
 said before, whether we 
 examine the human body, 
 or the comparative forms of 
 the bones, the distinctness 
 with which the spines and 
 processes are marked de- 
 clares the strength of the 
 muscles. It is particularly 
 pleasing to notice here the 
 correspondence between the 
 humerus and the other 
 bones, the scapula large 
 and with a double spine, 
 and great processes : the 
 ulna projecting at the ole- 
 cranon or elbow, and the 
 radius freely rotating : but 
 above all, we see in the 
 developement of one grand 
 metacarpal bone and its 
 corresponding phalanges, to which a strong claw 
 is attached, a very distinct provision for scratch- 
 
 * Tainanduu, from South America.
 
 OF THE ANT-EATER. 77 
 
 ing and turning aside the ant-hill. The whole 
 is an example of the relation of the particular 
 parts of the skeleton to one another ; for, were 
 it our business, it would be easy to show that as 
 there is a correspondence among the bones of 
 the arm, so is there a more universal relation 
 between those of the whole skeleton. As the 
 structure of the bones declares the provision of 
 the extremity for digging into the ant-hills, so 
 we shall not be disappointed in our expectation 
 of rinding a projecting muzzle unarmed with 
 teeth, and a long tongue provided with a gluti- 
 nous secretion, to lick up the emmets which are 
 disturbed by the animal's scratching. 
 
 In the skeleton of the cape-mole, we may see, 
 from the projection of the acromion scapulas, 
 and a remarkable process in the middle of the 
 humerus, that there is a provision for the rota- 
 tion of the arm, which implies burrowing. But 
 the apparatus is by no means so perfect as in 
 the common mole, so that we may infer that the 
 cape-mole digs in a softer soil, whilst the pos- 
 session of gnawing teeth indicates that it lives 
 on roots. 
 
 In BIRDS there is altogether a new condition 
 of the osseous system, as there is a new element 
 to contend with. The very peculiar form and 
 structure of their skeleton may be thus account- 
 ed for. First, it is necessary that birds, as they 
 are buoyed in the air ? be specifically lighter. 
 B. K
 
 78 STRUCTURE OF BIRDS. 
 
 Secondly, the circumference of their thorax 
 must be extended, and the motions of their ribs 
 limited, that the muscles of the wings may have 
 sufficient space and firmness for their attach- 
 ment. Both these objects are attained by a 
 modification of the apparatus for breathing. 
 The lungs are highly vascular and spongy, but 
 they are not distended with air. The air is 
 drawn through their substance, passing into the 
 large cavity common to the chest and abdomen; 
 and whilst the great office of decarbonization of 
 the blood is securely performed, advantage is 
 taken to let the air into all the cavities, even into 
 those of the bones. 
 
 From what was said in the introductory chap- 
 ter, of the weight of the body being a necessary 
 concomitant of muscular strength, we see why 
 birds, by reason of their lightness, as well as by 
 the conformation of their skeleton, walk badly. 
 And, on the other hand, in observing how this 
 lightness is adapted for flight, it is remarkable 
 how small an addition to their body will prevent 
 them rising on the wing. If the griffon-vulture 
 be frightened after his repast, he must disgorge, 
 before he flies; and the condor, in the same 
 circumstances, is taken by the Indians, like a 
 quadruped, by throwing the lasso over it.* 
 
 As every one must have observed, the breast- 
 
 * The subject is continued in the " Additional Illustrations."
 
 STRUCTURE OF BIRDS. 79 
 
 bone of birds extends the whole length of the 
 body, so as to cover the great cavity common to 
 the chest and abdomen, into which the air is 
 admitted ; and owing to this extension, a lesser 
 degree of motion suffices to respiration. Thus 
 a greater surface, necessary for the lodgement 
 and attachment of the muscles of the wings, is 
 obtained, whilst that surface is less disturbed 
 by the action of breathing, and is more steady. 
 Another peculiarity of the skeleton of the bird is 
 the consolidation of the vertebra of the back ; a 
 proof, if any were now necessary, that the whole 
 system of bones conforms to that of the extre- 
 mities, the firmer texture of the bones of the 
 trunk being a part of the provision for the 
 attachment of the muscles of the wings.* 
 
 The vertebrae of the back being fixed in 
 birds, and the pelvis reaching high, there is no 
 motion in the body ; indeed, if there were, it 
 would be interrupted by the sternum, or breast- 
 bone. We cannot but admire, therefore, the 
 structure of the neck and head, and how the 
 length and pliability of the vertebrae of the 
 neck, whilst they give to the bill the extent of 
 motion and office of a hand, become a substitu- 
 tion for the loss of flexibility in the body, by 
 enabling the bird to balance itself, as in stand- 
 ing, running, or flying. Is it not curious to 
 
 * The ostrich and cassowary, which are rather runners than 
 fliers, have the spine loose.
 
 80 STRUCTURE OF BIRDS. 
 
 observe how the whole skeleton is adapted to 
 this one object, the power of the wings. 
 
 Whilst the ostrich has no keel in its breast- 
 bone, birds of passage are recognisable, on dis- 
 section, by the depth of this ridge of the ster- 
 num. The reason is that the angle, formed by 
 this process and the body of the bone, affords 
 lodgement for the pectoral muscle, the powerful 
 muscle of the wing. In this sketch of the dis- 
 section of the swallow, there is a curious resem- 
 blance to the human arm ; and we cannot fail 
 to observe that the pectoral muscle constitutes
 
 STRUCTURE OF BIRDS. 81 
 
 the greater part of the bulk of the body.* And 
 here we see the correspondence between the 
 strength of this muscle and the rate of flying of 
 the swallow, which is a mile in a minute, for ten 
 hours every day, or six hundred miles a day.f 
 If it be true that birds, when migrating, require 
 a wind that blows against them,| it implies an 
 extraordinary power, as well as continuance of 
 muscular exertion. 
 
 We thus see how nature completes her work 
 when the intention is that the animal shall rise 
 buoyant and powerful in the air: the whole 
 texture of the frame is altered and made light, 
 in a manner consistent with strength. We see 
 also how the mechanism of the anterior extre- 
 mity is changed, and the muscles of the trunk 
 differently directed. But we are tempted to 
 examine those means, which we would almost 
 say are more awkwardly suited for their pur- 
 pose, where the system of bones and muscles, 
 
 * Borelli makes the pectoral muscles of a bird exceed in 
 weight all the other muscles taken together ; whilst he calculates 
 that the pectoral muscles of man are but a seventieth part of the 
 whole mass of the muscles. 
 
 f Mr. White says truly, that the swift lives on the wing ; it 
 eats, drinks, and collects materials for its nest while flying, and 
 never rests but during darkness. 
 
 I It is possible that the wind blowing near the ground in one 
 direction may be attended with the motion of a higher stratum of 
 the atmosphere in a contrary direction, and that, the idea of 
 migrating birds flying against the wind may have arisen from 
 this mistake.
 
 82 STRUCTURE ADAPTED 
 
 peculiar to the quadruped, is preserved, while a 
 power of launching into the air is also given. 
 We have already taken notice of the structure 
 of the bat as adapted to flight ; but there are 
 other animals which enjoy this function though 
 in a lesser degree. For example, the flying 
 squirrel (Petromys Volucella), being chased to 
 the end of the bough, spreads out its mantle, 
 which reaches along both its sides from the 
 anterior to the posterior extremity, and drops in 
 the air; and it is met during its descent with 
 such a resistance from its extended skin and its 
 bushy tail, that it can direct its flight obliquely 
 downwards, and even turn in the air. But to 
 this end, there is no necessity for any adapta- 
 tion of the anterior extremity. Among reptiles, 
 there is a provision of the same kind in the 
 Draco fimbriatus; which is capable, after creep- 
 ing to a height, of dropping safely to the 
 ground, under the protection of a sort of para- 
 chute, formed by its extended skin. This is not 
 an inapt illustration, for although the phalanges 
 of the fingers are not here used to extend the 
 web, the ribs, which are unnecessary for breath- 
 ing, are prolonged in a remarkable manner, and 
 upon them, like the whale-bone of an umbrella, 
 the skin is expanded. 
 
 But this brings us to a very curious subject, 
 the condition of some of those Saurian reptiles, 
 the remains of which are found only in a fossil
 
 FOR FLYING. 83 
 
 state, in what are termed the ancient strata of 
 the Jura. The Pterodactyle of Cuvier is an 
 animal which seems to confound all our notions 
 of system. Its mouth was like the long bill of a 
 bird, and its flexible neck corresponded ; but 
 it had teeth in its jaws like those of a crocodile. 
 It had the bones of the anterior extremity pror 
 longed, and fashioned somewhat like those in 
 the wing of a bird ; but it could not have had 
 feathers, as it had not a proper bill. We see no 
 creature having feathers without a bill to dress 
 and prin them. Nor did this extremity resemble 
 in its structure that of a bat : instead of the pha- 
 langes or rows of bones of all the fingers being 
 equally prolonged, as in the bat, the second fin- 
 ger only was extended to an extraordinary length, 
 whilst the third, fourth, and fifth had the length 
 and articulation of those of a quadruped, and they 
 were terminated with sharp nails, corresponding 
 with the pointed teeth. The extended metacarpal 
 bone and phalanges reached to double the whole 
 length of the animal, and the conjecture is, that 
 there was extended upon them a membrane re- 
 sembling that of the Draco fimbriatus. In the 
 imperfect specimens which we have to found our 
 reasoning upon, we cannot discover either in the 
 height of the pelvis, the strength of the vertebrae 
 of the back, or the expansion of the sternum, a 
 provision for the attachment of muscles com- 
 mensurate with the extent of the supposed wing.
 
 84 
 
 ANATOMY 
 
 The humerus, and the bones which we presume 
 to be the scapula and coracoid, bear some cor- 
 respondence to the extent of the wing ; but the 
 extraordinary circumstance of all is the size and 
 strength of the bones of the jaw and vertebrae of 
 the neck, compared with the smallness of the 
 body, and the extreme delicacy of the ribs ; 
 which make it, altogether, the thing the most 
 incomprehensible in nature. 
 
 OF THE RADIUS AND ULNA. 
 
 The easy motion of the hand, we might ima- 
 gine to result from the structure of the hand 
 itself; but, on the contrary, the movements 
 which appear to belong to it, are divided among 
 all the bones of the extremity.* 
 
 The head of the humerus is rotatory on the 
 scapula, as when making the guards in fencing; 
 but the easier and finer rolling of the wrist is 
 
 * In this sketch, the upper bone of the fore-arm is the radius, 
 and in revolving on the lower bone, the ulna, it carries the hand 
 with it.
 
 OF THE RADIUS AND ULNA. 83 
 
 accomplished by the motion of the radius on the 
 ulna. 
 
 The ulna has a hooked process, the olecranon, 
 or projecting bone of the elbow, which catches 
 round the lower end of the humerus or arm bone, 
 (this articulating portion is called trochlea), and 
 forms with it a hinge joint. The radius, again, 
 at the elbow, has a small, neat, round head, 
 which is bound to the ulna by ligaments, as a 
 spindle is held in the bush ; and it has a de- 
 pression with a polished surface for revolving on 
 the condyle of the humerus. This bone turns 
 on its long axis, rolling upon the ulna both at 
 the elbow and wrist-joint ; and, as it turns, it 
 carries the hand with it, because the hand is 
 strictly attached to its lower head alone. This 
 rolling, is what is termed pronation and supina- 
 tion. 
 
 Such a motion would be useless, and a source 
 of weakness in an animal that had a solid hoof. 
 Accordingly, in the horse, these bones are united 
 together, and consolidated in the position of pro- 
 nation. 
 
 But let us extend our views before we take 
 the particular instance. There is indeed some- 
 thing so highly interesting in the conformation 
 of the whole skeleton of an animal, and the 
 adaptation of any one part to all the other parts, 
 that we must not let our reader remain ignorant 
 of the facts, or of the important conclusions
 
 6(3 ANATOMY 
 
 drawn from them. What we have to state has 
 been the result of the studies of many natu- 
 ralists ; but although they have laboured, as it 
 were, in their own department of comparative 
 anatomy, they have failed to seize upon it with 
 the privilege of genius, and to handle it in the 
 masterly manner of Cuvier. 
 
 Suppose a man ignorant of anatomy to pick 
 up a bone in an unexplored country, he learns 
 nothing, except that some animal has lived and 
 died there; but the anatomist can, by that 
 single bone, estimate, not merely the size of the 
 animal, as well as if he saw the print of its foot, 
 but the form and joints of the skeleton, the 
 structure of its jaws and teeth, the nature of 
 its food, and its internal economy. This, to one 
 ignorant of the subject, must appear wonderful, 
 but it is after this manner that the anatomist 
 proceeds. Let us suppose that he has taken 
 up that portion of bone in the limb of the 
 quadruped which corresponds to the human 
 radius ; and that he finds that the form of the 
 bone does not admit of free motion in various 
 directions, like the paw of the carnivorous crea- 
 ture. It is obvious, by the structure of the part, 
 that the limb must have been merely for sup- 
 porting the animal, and for progression, and not 
 for seizing prey. This leads him to the fact 
 that there were no bones resembling those of 
 the hand and fingers, or those of the claws of
 
 OF THE RADIUS AND ULNA. 87 
 
 the tiger ; for the motions which that conforma- 
 tion of bones permits in the paw, would be use- 
 less, without the rotation of the wrist he con- 
 cludes that these bones were formed in one 
 mass, like the cannon bone, pastern bones, and 
 coffin bone of the horse's foot.* 
 
 The motion of the foot of a hoofed animal, 
 limited to flexion and extension, implies the 
 absence of a collar bone and a restrained motion 
 in the shoulder joint; and thus the naturalist, 
 from the specimen in his hand, has got a perfect 
 notion of all the bones of the anterior extremity ! 
 The motions of the extremities imply a con- 
 dition of the spine which unites them. Each 
 bone of the spine will have that form which 
 permits the bounding of the stag, or the gallop- 
 ing of the horse, but it will not have that manner 
 of joining which admits of the turning or writh- 
 ing of the spine, as in the leopard or the tiger. 
 
 And now he comes to the head : the teeth 
 of a carnivorous animal, he says, would be use- 
 less to rend prey, unless there were claws to 
 hold it, and a mobility of the extremities like 
 that of the hand, to grasp it. He considers, 
 therefore, that the front teeth must have been 
 for brousing, and the back teeth for grinding. 
 
 * For these are solid bones, where it is difficult to recognise 
 any resemblance to the metacarpus and bones of the fingers; 
 and yet comparative anatomy proves that the latter bones are of 
 the same class with those in the solidungula,
 
 88 ANATOMY 
 
 The socketing of the teeth in the jaws gives a 
 peculiar form to these bones, and the muscles 
 which move them are also peculiar ; in short, he 
 forms a conception of the shape of the skull. 
 From this point he may set out anew, for by the 
 form of the teeth, he ascertains the nature of the 
 stomach, the length of the intestines, and all 
 the peculiarities which mark a vegetable feeder. 
 
 Thus the whole parts of the animal system 
 are so connected with one another, that from 
 one single bone or fragment of bone, be it of the 
 jaw, or of the spine, or of the extremity, a really 
 accurate conception of the shape, motions, and 
 habits of the animal, may be formed. 
 
 It will readily be understood that the same 
 process of reasoning will ascertain, from a small 
 portion of a skeleton, the existence of a carni- 
 vorous animal, or of a fowl, or of a bat, or of 
 a lizard, or of a fish ; and what a conviction is 
 here brought home to us, of the extent of that 
 plan which adapts the members of every crea- 
 ture to their proper office, and yet exhibits one 
 system to pervade the whole range of animated 
 beings whose motions are conducted by the ope- 
 ration of muscles and bones ! 
 
 After all, this is but a part of the wonders 
 disclosed through the knowledge of a thing so 
 despised as a fragment of bone. It carries us 
 into another science ; since the knowledge of the 
 skeleton not only teaches us the classification of
 
 OP THE RADIUS AND ULNA. 89 
 
 creatures now alive, but affords proofs of the 
 former existence of animated beings which are 
 not now to be found on the surface of the earth. 
 We are thus led to an unexpected conclusion 
 from such premises : not merely of the exist- 
 ence of an individual animal, or race of ani- 
 mals ; but even the changes which the globe has 
 undergone in times before all existing records, 
 and before the creation of human beings to in- 
 habit the earth, are opened to our contempla- 
 tion. 
 
 To return to our particular subject, we readily 
 comprehend how it happens that if the geologist 
 should find the nearer head of the radius, resem- 
 bling this sketch, and see in the extremity of it 
 
 a smooth depression (A), where it bears against 
 the hunierus, and the polished circle (B) that 
 turns on the cavity of the ulna, he would 
 say, this animal had a paw it had a motion 
 at the wrist, which implies claws. But claws 
 may belong to two species of animals : the feline, 
 which possesses sharp carnivorous teeth, or to 
 B. M
 
 90 COMPARATIVE ANATOMY 
 
 animals without either canine or cutting teeth, 
 the Edentata. If he should find the lower ex- 
 tremity of this same bone, and observe on it 
 spines and grooves for distinct tendons which 
 disperse to the phalanges instead of running to 
 be inserted into a single bone, he would con- 
 clude that there must have been moveable claws 
 that it belonged to a carnivorous animal ; and 
 he would seek for canine teeth of corresponding 
 size. 
 
 THE LAST DIVISION OF THE BONES OF THE ARM. 
 
 In the human hand, the bones of the wrist 
 (carpus) are eight in number ; and they are so 
 closely connected that they form a sort of ball, 
 which moves on the end of the radius. Beyond 
 these, and towards the fingers, forming the palm 
 of the hand, are the metacarpal bones, which 
 diverge at their further extremities, and give 
 support to the bones of the fingers. The thumb 
 has no metacarpal bone, and is directly articu- 
 lated with the carpus or wrist. There are thus 
 in the hand twenty-nine bones, from the mecha- 
 nism of which result strength, mobility and elas- 
 ticity. 
 
 Lovers of system (I do not use the term dis- 
 paragingly) delight to trace the gradual sub-
 
 OF THE WRIST AND HAND. 91 
 
 traction of the bones of the hand. Thus, look- 
 ing to the hand of man, they see the thumb fully 
 formed. In the siniiae they find it exceedingly 
 small; in one of them, the spider- monkey, it 
 has disappeared, and the four fingers are suf- 
 ficient, with hardly the rudiments of a thumb. 
 In some of the tardigrade animals, as we have 
 seen (in page 30) there are only three metacarpal 
 bones with three fingers. In the horse, the can- 
 non bone may be shewn to consist of two meta- 
 carpal bones. Indeed, we might go further and 
 instance the wing of the bird. To me, this 
 appears to be losing the sense in the love of 
 system. There is no regular gradation, but, as 
 I have often to repeat, a variety most curiously 
 adapting the same system of parts to every 
 necessary purpose. 
 
 In a comparative view of these bones, we are 
 led more particularly to take notice of the foot 
 of the horse. It is universally admitted to be of 
 beautiful design, and calculated for strength and 
 elasticity, and especially provided against con- 
 cussion. 
 
 The bones of the fore-leg of the horse become 
 firmer as we trace them downwards. The two 
 bones corresponding with those of the fore-arm, 
 are braced together and consolidated ; and the 
 motion at the elbow joint is limited to flexion 
 and extension. The carpus, forming what by a 
 sort of license is called the knee, is also newly
 
 5)2 ACTION OF THE SPLINT BONES 
 
 modelled ; but the metacarpal bones and pha- 
 langes of the fingers are totally changed, and can 
 hardly be recognised. When we look in front, 
 instead of the four metacarpal bones we see one 
 strong bone, the cannon bone ; and posterior to 
 this, we find two lesser bones, called splint bones. 
 The heads of these lesser bones enter into the 
 knee-joint ; but at their lower ends they dimi- 
 nish gradually, and they are held by an elastic 
 ligamentous attachment to the sides of the can- 
 non bone. 
 
 I have some hesitation in admitting the cor- 
 rectness of the opinion of veterinary surgeons 
 on this curious piece of mechanism. They 
 imagine that these moveable splint bones, by 
 playing up and down as the foot is alternately 
 raised and pressed to the ground, bestow elas- 
 ticity and prevent concussion. The fact cer- 
 tainly is that by over action this part becomes 
 inflamed, and the extremities preternaturally 
 joined by bone to the greater metacarpal or 
 cannon bone; and that this, which is called a 
 splint, is a cause of lameness. 
 
 I suspect, rather, that in the perfect state of 
 the joint, these lesser metacarpal bones act as a 
 spring to throw out the foot, when it is raised 
 and the knee-joint bent. If we admit that it is 
 the quickness in the extension of this joint on 
 which the rate of motion must principally de- 
 pend, it will not escape observation, that in the
 
 IN THE HORSE S LEG. 
 
 93 
 
 bent position of the knee, the extensor tendons 
 have very little power, from their running so near 
 to the centre of motion in the joint ; and that, 
 in fact, they require some additional means to 
 aid the extension of the leg. 
 
 Suppose that the head of the lesser metacarpal 
 bone A enters into the composition of the joint, 
 it does not appear that by its yielding when the 
 foot is upon the ground, the bones of the carpus 
 can descend, as long as they are sustained by the 
 greater metacarpal or cannon bone. I do not* 
 therefore, conceive that this bone can add to the
 
 94 OF THE HORSE'S FOOT. 
 
 elasticity of the foot. But when we perceive 
 that the head of the splint bone is behind the 
 centre of motion in the joint, it is obvious that it 
 must be more pressed upon in the bent condi- 
 tion of the joint, when the foot is elevated ; and 
 that then the bone must descend. If the splint 
 bone be depressed when the limb is raised and 
 bent, and have a power of recoiling (which it 
 certainly has), it must aid in throwing out the 
 leg into the straight position and assist the 
 extensor muscles of the knee. Further, we can 
 readily believe that when the elasticity of these 
 splint bones is lost, by ossification uniting them 
 firmly to the cannon bone, the want of such a 
 piece of mechanism, essential to the quick ex- 
 tension of the foot, will make the horse apt to 
 come down. 
 
 In looking to this sketch and comparing it 
 with that of the hand on page 84, we see that in 
 the horse's leg the five bones of the first digital 
 phalanx are consolidated into the large pastern 
 bone ; those of the second phalanx into the 
 lesser pastern or coronet ; and those of the last 
 phalanx into the coffin bone. 
 
 OF THE HORSE'S FOOT. Nothing is better suited 
 to illustrate our subject than the horse's foot. It 
 is a most perfect piece of mechanism ; and 
 whilst examining it, we shall be able to infer the 
 peculiarity of living mechanism, that it can be 
 preserved perfect, solely by the natural exercise
 
 OF THE HORSE'S FOOT. 95 
 
 of its parts. The horse, a native of extensive 
 plains and steppes, has a structure admirably 
 suited to these his natural pasture grounds. 
 When brought, however, into subjection, and 
 running on our hard roads, his feet suffer from 
 concussion. The value of the horse, so often 
 impaired by lameness of the foot, has made this 
 part an object of great interest; and I have it 
 from the excellent professor of veterinary sur- 
 gery to say that he has never demonstrated the 
 anatomy of the horse's foot without finding 
 something new to admire. 
 
 The weight and power of the annual require 
 that he should have a foot in which strength 
 and elasticity are combined. The first thing 
 that attracts attention is the position of the 
 bones. Had they been placed the one directly 
 over the other, there could have been no elasti- 
 city; but on the contrary they are placed ob- 
 liquely over each other, and a strong elastic 
 ligament runs along behind them, terminating 
 by an attachment to the lowest or coffin bone.* 
 So essential is the obliquity of the bones 
 
 * The convexity of the bone, the elastic ligament, and the 
 tendons behind the cannon bone, can be distinguished by the 
 eye, and by the hand, and constitute one of the " points" of a 
 horse ; because there is so perfect a correspondence between the 
 strength of an animal's bones, tendons, and muscles, that in 
 those sinews the jockey sees the perfection, or the defect of the 
 whole.
 
 06 OF THE HORSE'S FOOT. 
 
 to the elasticity of the limb, that by observing 
 the position of the pastern bones, and coffin 
 bone, it is possible to say whether or not a horse 
 goes easily without mounting it. 
 
 The bones of the foot of the camel rest on a 
 soft elastic cushion. There is a texture of the 
 same kind in the horse's foot, but it acts very 
 differently and never comes to the ground ; nor 
 indeed does the sole of the horse's foot bear its 
 weight. The horny frog, the triangular projec- 
 tion in the hollow of the hoof, has above it this 
 elastic frog or cushion. These are essential 
 parts, inasmuch as receiving the weight of the 
 animal, they press out the crust, or that part 
 of the horny hoof which we see when the foot 
 is on the ground. The anterior tip of this crust, 
 or the part which last touches the ground as 
 the foot rises, is very dense and firm, to with- 
 stand the pressure against the ground and the 
 impulse forward : the lateral part of the crust, 
 however, is more elastic, and on its play de- 
 pends that elasticity of the foot which prevents 
 concussion. 
 
 This crust is not consolidated with the bone 
 called coffin bone ; for, between them there are 
 elastic laminae. When the animal puts his foot 
 to the ground, the weight bearing on the coffin 
 bone, and this bone being attached by these 
 elastic laminae to the circle of the crust, the lateral 
 parts yield, and the weight is sustained by the
 
 OF THE HORSE'S FOOT. 97 
 
 margin of the crust; the sole never touching 
 the ground, unless it has become diseased. 
 
 Xenophon, speaking of the Persian horses, 
 says that their grooms are careful to curry them 
 on a pavement of round stones, that by beating 
 their feet against a firm and irregular surface the 
 texture of the foot may be put into exercise. It 
 corresponds curiously with this, that our high-bred 
 horses are subject to a disease of the foot, from 
 which our heavy draught horses, and Flanders 
 horses are exempt. Horses for the turf move 
 with the foot close to the ground ; no time is lost 
 in lifting high the foot in the semicircle, the 
 race horse being light ; and the foot coming thus 
 down gently, it wants the full play of the appa- 
 ratus, whilst the heavy horse with less blood, lifts 
 its foot in a circle and comes forcibly on the 
 ground. Hence it may be understood how the 
 lighter horse is subject to contractions of the 
 foot. The bones, ligaments, and crust are out of 
 use, the sole becomes firm as a board, the sides 
 of the crust are permanently contracted, the 
 parts have no longer their elastic play, and the 
 foot striking our hard pavement suffers a shock 
 or concussion ; then comes " a fever of the 
 foot," which is inflammation, and that goes on 
 to its total destruction. The proof of all this is, 
 that by paring and softening the exterior of the 
 hoof, so as to restore its elasticity, the veterinary 
 surgeon cures this contracted foot, unless the
 
 W CONTRAST OF THE 
 
 inflammation has been permitted to destroy the 
 fine apparatus entirely. 
 
 That there is a relation between the internal 
 structure and the covering, whether it be the 
 nail, or crust, or cloven hoof, we can hardly 
 doubt : and an unexpected proof of this offers 
 itself in the horse. There are some very rare 
 instances of a horse having digital extremities. 
 According to Suetonius, there was such an ani- 
 mal in the stables of Caesar ; another was in the 
 possession of Leo X. ; and Geoffroy St. Hilaire, 
 in addition to those, says, that he has seen a 
 horse with three toes on the fore- foot, and four 
 on the hind-foot.* These instances of deviation 
 in the natural structure of the bones were accom- 
 panied with a corresponding change in the 
 coverings the toes had nails, not hoofs. 
 
 By these examples, it is made to appear still 
 more distinctly that there is a relation between 
 the internal configuration of the toes and their 
 coverings that when there are five toes com- 
 plete in their bones, they are provided with per- 
 fect nails when two toes represent the whole, 
 as in the cleft foot of the ruminant, there are 
 appropriate horny coverings and that when the 
 bones are joined to form the pastern bones and 
 coffin bone, there is a hoof or crust, as in the 
 horse, couagga, zebra, and ass. 
 
 * Such a horse was not long since exhibited in Town, and at 
 Newmarket.
 
 FOOT OF RUMINANTS. 
 
 99 
 
 In ruminants there is a cannon bone, but the 
 foot is split into two parts, and this must add to 
 its spring or elasticity. I am inclined to think 
 that there is still another intention in this form ; 
 it prevents the foot sinking in soft ground, and 
 permits it to be more easily withdrawn. We 
 may observe how much more easily the cow 
 withdraws her foot from the yielding margin of 
 a river, than the horse. The round and concave 
 form of the horse's foot is attended with a va- 
 cuum or suction as it is withdrawn ; while the 
 split and conical shaped hoof expands in sink- 
 ing, and is easily extricated. 
 
 In the chamois and other species of the deer 
 
 The left hand figure represents the bones of the foot of the 
 antelope ; the right, those of the rein-deer.
 
 100 CONTRAST OF THE 
 
 there is an additional toe. A sort of lesser 
 cannon bone, with its two pasterns, supports this 
 toe, and is joined by ligament to the larger 
 cannon bone, so that it must have great elas- 
 ticity. As a division of the flexor tendon runs 
 into it, it must increase the spring when the 
 animal rises from its crouching position. We 
 see, in these sketches, that the lesser metacarpal 
 bone, which, in the horse, entered into the joint 
 of the " knee," as the splint-bone, is here brought 
 down to increase the elasticity, or to expand the 
 foot. 
 
 The two lateral toes of the hog are short, and 
 do not touch the ground, yet they must serve to 
 sustain the animal when the foot sinks. In the 
 rein-deer these bones are strong and deep, and 
 the toe, by projecting backwards, extends the 
 foot horizontally thus giving the animal a 
 broader base to stand on, and adapting it to 
 the snows of Lapland, on the principle of the 
 snow-shoe. The systematic naturalist will call 
 these changes in the size, number, and place of 
 the metacarpal bones " gradations ; " I see in 
 them only new proofs of the same system of 
 bones being applicable to every circumstance, 
 or condition of animals, and furnishing us with 
 other instances of adaptation. 
 
 I have explained why I think that the bones 
 of the elephant's leg stand so perpendicularly 
 over each other ; there is a peculiarity also in the
 
 ELEPHANT AND CAMEL. 101 
 
 bones of the foot. In the foot of the living ani- 
 mal we see only a round pliant mass, which, 
 when he stands, resembles the base of a pillar, 
 or the lower part of the trunk of a stately tree. 
 But when we examine the bones of the foot, we 
 find this broad base to consist of the carpus, 
 metacarpus, and phalanges of the toes ; and 
 these bones have a very different use from what 
 we have hitherto noticed. They are not con- 
 nected with a moveable radius, and have no 
 individual motion, as in the carnivorous animal 
 they merely serve to expand the foot, the base 
 of the column, and to give it a certain elasticity. 
 
 In the sketch (page 62) I have placed the 
 bones of the foot of the camel in contrast with 
 those of the elephant. The camel's foot having 
 no such disproportion ed weight to bear as in the 
 elephant, lightness of motion is secured by the 
 oblique position of its bones, as well as by the 
 direction of the bones of the shoulder, which we 
 have formerly noticed. In the soft texture of 
 the camel's foot there is much to admire ; for 
 although the bottom be flat, like the sole of a 
 shoe, yet, as we have said, there is between it 
 and the bones and tendons a cushion so soft 
 and elastic that the animal treads with great 
 lightness and security. The resemblance of the 
 foot of the ostrich to that of the camel has not 
 escaped naturalists. 
 
 We are now treating of the last bones of the 
 
 E. N
 
 10*2 MECHANISM OF 
 
 fingers ; and let us once more see what may be 
 done, by the study of one of these bones, to the 
 bodying forth of the whole animal. I allude to 
 the dissertations of the President Jefferson and 
 Baron Cuvier on the Megalonix. We must pre- 
 face this part of our subject by some remarks on 
 the form of the claws of the lion. 
 
 The canine tribe are carnivorous, like the 
 feline, and both have the last bones of their toes 
 armed with a nail or claw. But their habits and 
 their means of obtaining food are different. The 
 first combine a keen sense of smelling with a 
 power of continued speed ; they run down their 
 prey. The feline order have their superiority 
 in the fineness of their sight, accompanied with 
 a patience, watchfulness, and stealthy move- 
 ment ; they spring upon their prey, and never 
 long pursue it. They attain their object in a 
 few bounds, and, failing, sulkily resume their 
 watch. When we look to the claws, we see a 
 correspondence with those habits. The claws of 
 the dog and wolf are coarse and strong, and 
 bear the pressure and friction incident to a long 
 chase. They are calculated to sustain and pro- 
 tect the foot. But the tiger leaps on his prey, 
 and fastens his sharp and crooked claws in the 
 flesh. These claws being curved and sharp, we 
 must admire the mechanism by which they are 
 preserved. The last bone, that which supports 
 the claw, is placed laterally to the penultimate 
 bone, and is so articulated with it, that an elastic
 
 THE LION'S CLAW. 
 
 103 
 
 ligament (A) draws it back and raises the sharp 
 extremity of the claw upwards. The nearer 
 extremity of the furthest bone presses the ground, 
 in the ordinary running of the animal,* whilst 
 
 the claw is thus retracted into a sheath. But 
 when the tiger makes his spring and strikes, the 
 claws are uncased by the action of the flexor 
 tendons ; and they are so sharp and strong in 
 
 * The pads in the bottom of the lion's foot cover these bones, 
 or rather, we would say, protect them ; they are soft cushions, 
 which add to the elasticity of the foot, and must, in some degree, 
 defend the animal in alighting from its bound. I could not 
 comprehend how the powerful flexor muscles did not unsheath 
 the claws when the lion made its spring, and how they produced 
 this effect when there was an excitement to seize and hold the 
 prey I made this dissection to detect the cause. The last bone 
 of the toe is placed, in relation to the penultimate, in so peculiar 
 a manner, being drawn back by the elastic ligament (A) beyond
 
 104 PRESIDENT JEFFERSON AND CUVIER. 
 
 the Bengal tiger, and his arm is so powerful, 
 that they have been known to fracture a man's 
 skull by a touch, in the act of leaping over 
 him. 
 
 I have alluded to the observations of Presi- 
 dent Jefferson on the Megalonix. Having found 
 a bone, which, by its articulating surface and 
 general form, he recognised to be one of the 
 bones of the phajanx of an animal of great size, 
 he thought he could discover that it had carried 
 a claw; and from this circumstance, lie natu- 
 rally enough concluded (according to the adage 
 ex ungue leonem) that it must have belonged 
 to a carnivorous animal. He next set about cal- 
 
 culating the length of this claw, and estimating 
 
 the centre of motion of the joint, that the flexor tendon (B) acting 
 upon it, when the animal uses his foot in mere progression, 
 forces the nearer end, and the cushion of the toe to the ground. 
 But when the lion strikes his prey to seize it, a more general 
 excitement takes place in the muscles called interossei, and the 
 extensors, D, E ; the relative position of the two last bones is 
 altered ; the nearer end of the last bone is withdrawn from 
 beyond the centre of motion of the joint, so that the action of 
 the flexor tendon can now draw it forward thus unsheathing 
 and uncovering the claw, and preparing it to hold or to tear.
 
 PRESIDENT JEFFERSON AND CUVIER. 105 
 
 the size of the animal. He satisfied himself that 
 in this bone, a relick of the ancient world, he 
 had obtained a proof of the existence, during 
 these old times, of a lion of the height of the 
 largest ox, and an opponent fit to cope with the 
 mastodon. But when this bone came under the 
 scrutiny of Baron Cuvier, his perfect knowledge 
 of anatomy enabled him to draw a different con- 
 clusion. 
 
 He first observed that there was a spine in the 
 middle of the articulating surface of the last 
 bone ; which in this respect was unlike the form 
 of the same bone in the feline tribe. He found 
 no provision in this specimen of an extinct ani- 
 mal for the lateral attachment of the bone ; 
 which we have just shown to be necessary for 
 its retraction. Then observing what segment of 
 a circle this bone formed, he prolonged the line 
 in the corresponding circumference, and showed 
 that the claw belonging to it must have been of 
 such great length, that it could never have been 
 retracted to the effect of guarding an acute and 
 sharp point. The point, therefore, could not 
 have been raised vertically, as in the lion, so as 
 to have permitted the animal to put the foot to 
 the ground without blunting the instrument ! 
 Pursuing such a comparison, he rejected the 
 idea of the bone belonging to an animal of the 
 feline tribe at all. His attention was directed 
 
 u. o
 
 106 ON THE MEGALON1X. 
 
 to another order, the paresseux or sloths, which 
 have great toes and long nails (p. 30). Their 
 nails are folded up in a different fashion ; they 
 just enable the animal to walk ; but slowly and 
 awkwardly, somewhat in the same manner as if 
 we were to fold our fingers on the palm of the 
 hand, and bear upon our knuckles. On insti- 
 tuting a more just comparison between these 
 bones of the ancient animal and the correspond- 
 ing bones of the paresseux, he has satisfied us 
 that the lion of the American President was an 
 animal which scratched the ground and fed on 
 roots. 
 
 One experiences something like relief to find 
 that there never was such an enormous car- 
 nivorous animal as this denominated megalonix. 
 
 These unguical bones, or bones of the claws, 
 exhibit a very remarkable correspondence with 
 the habits and general forms of animals. Besides 
 what we have seen in the lion, or tiger, in the 
 dog or wolf, in the bear, and ant-eater, there is 
 a variety, where we should least expect it, in 
 the animals that live in woods, and climb the 
 branches of trees. The squirrel, with claws set 
 both ways, runs with equal facility up and down 
 the bole, and nestles in the angles of the 
 branches. The monkey leaps and swings him- 
 self from branch to branch, and springing parts 
 with his hold by the hinder extremities, before
 
 FOOT OF THE QUADRUMANA. 107 
 
 he reaches another with the anterior extremities ; 
 he leaps the intervening space, and catches with 
 singular precision. But the sloths do not grasp ; 
 their fingers are like hooks, and their strength 
 is in their arms. They do not hold, but hang 
 to the branch. They never let go with one set 
 of hooks, until they have caught with the other, 
 and thus they use both hind and fore feet, whilst 
 their bodies are pendant. Here we see, once 
 more, the form of the extremity, the concentra- 
 tion of strength, and the habits of animals, con- 
 forming not merely to their haunts in the forest, 
 but to their mode of moving and living among 
 the branches; all active, but in a different 
 manner. 
 
 There have been of late deposited in our 
 Museum in the College of Surgeons, the bones 
 of an animal of great size ; and the examination 
 of these gives us an opportunity of applying the 
 principles and the mode of investigation followed 
 by our great authority in this part of science. 
 These remains consist of part of the head, spine, 
 tail, pelvis, and the bones of one hinder extre- 
 mity, and the scapula. Estimating the animal 
 to which they belonged at seven feet in height, 
 it scarcely conveys an adequate idea of its size ; 
 for the thigh-bone is three times the diameter ol 
 that of the large elephant which is in the same 
 collection, and the pelvis or haunch-bone, twice
 
 108 MEGATHERIUM. 
 
 the breadth of that of the same animal. Form- 
 ing our opinion of it on these principles to which 
 we have had repeated occasion to refer in this 
 essay, and judging by the strength and promi- 
 nence of the processes of these bones, the animal 
 must have possessed great muscular power ; and 
 directed by the same circumstances still, we can 
 form an idea of the manner in which that mus- 
 cular power was employed. 
 
 On comparing these bones with the drawings 
 of the skeleton of the enormous animal which is 
 preserved in the Royal Museum of Madrid, it is 
 seen, at once, that this new acquisition is part of 
 the remains of the great fossil animal of Para- 
 guay, the Megatherium of Cuvier. Every obser- 
 vation which we are enabled to make on the ex- 
 treme bones of the foot, on the scapula, and on 
 the teeth, confirms the idea entertained by Cuvier, 
 that it was a vegetable feeder ; and that its great 
 strength was employed in flinging up the soil 
 and digging for roots. Its strength seems to 
 have been concentrated to its paws, correspond- 
 ing with the provisions there for enormous nails 
 or claws. I have heard it surmised that this 
 animal may have sat upon its hinder extremities, 
 and pulled down the branches of trees to feed 
 upon. It is only its great size there that can 
 countenance such an idea. We have not the 
 humerus, which by its processes would have de-
 
 AMPHIBIA. 109 
 
 clared the classification and activity of its mus- 
 cles : but we can estimate the height, breadth, 
 and strength of the animal by the pelvis and 
 enormous bones of the posterior extremity ; 
 while by the scapula and clavicle we can Torm 
 a conception of the extent of motion of the 
 anterior extremity, and the great power that it 
 possessed. In short, by the osseous and mus- 
 cular systems we perceive that the strength of 
 the Megatherium was not so much in the body, 
 certainly not in the jaws, but was directed rather 
 to the extremities ; and that it was given neither 
 for rapidity of motion nor offence, but for dig- 
 ging. 
 
 How little was it to be expected that an 
 alliance between anatomy, the most despised 
 part of it, and mineralogy, was to give rise to 
 a new science ; making a part of natural his- 
 tory which had been pursued in mere idleness, 
 vaguely, and somewhat fancifully, to be hence- 
 forth studied philosophically, and by inductive 
 reasoning. It is both interesting and instructive 
 to find the relations thus established between 
 departments of knowledge apparently so remote. 
 
 In the true Amphibia, as the phoca and wal- 
 rus, we have the feet contracted, and almost 
 enveloped in the skin, and the fingers webbed 
 and converted into fins. 
 
 We have sketched here the bones of the 
 morse, or walrus, and they are remarkably com- 
 
 B. P
 
 110 BONES tN THE CETACEA. 
 
 plete, if we consider the peculiar appearance of 
 the feet in the living animal. The bones are 
 
 accommodated to be an instrument for swim- 
 ming ; for these animals live in the water, and 
 come to land only to suckle their young, or to 
 bask in the sun ; and out of the water they are 
 the most unwieldy and helpless of all animals 
 which breathe. 
 
 In the Cetacea, for example, in the whales, 
 we have mammalia unprovided with hind feet. 
 The scapula is large, the humerus very short, 
 and the bones of the fore-arm and hand flattened
 
 BONES IN THE CETACEA. 
 
 Ill 
 
 and confined in membranes which convert them 
 into a fin. These animals live in the water, but 
 they must rise to the surface to breathe. 
 
 I need not say that in the dolphin we recog- 
 
 nise the bones of the anterior extremity, only a 
 little further removed from the forms which we 
 have hitherto been contemplating. The seal 
 and morse raise themselves out of the water 
 and lie on the rocks ; but the different species of 
 the dolphin continue always in the water; the 
 extremity is now a fin or an oar, and those who 
 have seen the porpoise or the pelloch in a 
 stormy sea, must acknowledge how complete 
 the apparatus is, through which they enjoy their 
 element.
 
 112 
 
 BONES OF THE ICHTHYOSAURUS 
 
 The last examples I select, shall be from the 
 ancient world.* 
 
 These figures are taken from specimens, in 
 
 oQQP 
 
 * The figure to the left is the anterior extremity of the Plesio- 
 saurus ; to the right, that of the Ichthyosaurus. In these paddles 
 we see the intermediate changes from the foot of animals to the 
 fin of the fish from the walrus, dolphin, turtle, to the plesio- 
 saurus, and ichthyosaurus where we no longer find the pha- 
 langes or attempt to count the bones ; and where they become 
 irregular polygons or trapezoids less like phalanges than the 
 radii of the fins of a fish. In fishes the anterior extremity is 
 recognised in the thoracic fin; and we may even discover the 
 prototypes of the scapula and the bones of the arm connected 
 with it. I know not what the naturalist, who likes to note the 
 gradual decrease of the elementary parts, makes of these hun-
 
 AND PLESIOSAURUS. 1 13 
 
 the College of Surgeons, of fossil animals of 
 singular structure, between the crocodile and 
 the fish. They are in a calcareous rock, and 
 the skeletons are entire, but crushed, and a good 
 deal disfigured. Here are the extremities or 
 paddles, consisting of a multitude of bones 
 articulated ; and among these we still discover 
 the humerus, radius and ulna, and bones of the 
 carpus and fingers. No fault is to be found 
 with the construction of these instruments; they 
 are suited to their offices, and no bone is super- 
 fluous, or misplaced, or imperfect. The ichthy- 
 osaurus and plesiosarus (the animals which offer 
 these specimens) inhabited the sea; their re- 
 mains are found low in the lias deposit; great 
 changes have been wrought on the land and on 
 the deep since they existed ; and the race of 
 animals, the structure of whose extremities we 
 have been engaged in examining, was not then 
 in being. When we discover the same series of 
 bones in the animals of the old world as there is 
 in those now alive, we admit the existence of the 
 same system ; and we must necessarily acknow- 
 ledge the progressive developement of that 
 system, through a period of time incalculably 
 remote ; even if, instead of our days and years, 
 referable to history, each day were as a thou- 
 
 dred bones of the paddle or of the fin ; where there is an increase 
 of the number, whilst, relatively speaking, there is a defect in the 
 form and motion, of the parts.
 
 114 PECULIARITIES IN THE HAND, 
 
 sand years, or we were to make our estimate by 
 the records of the revolutions which have left 
 their traces on the globe itself.* 
 
 I have now given, I hope, sufficient examples 
 of the changes in the bones of the anterior ex- 
 tremity, which suit them to every possible 
 variety of use. After a little attention to the 
 form of the bones of the human hand, I shall 
 take up another division of my subject. 
 
 In this sketch we have the bones of the paw 
 of the adult Chimpanzee, from Borneo ; and the 
 
 * The wood-cuts on this page give some idea of the forms of 
 the skeletons of the ichthyosaurus and plesiosaurus restored by 
 the Rev. Mr. Conybeare.
 
 AND IN THE THUMB AND FINGERS. 115 
 
 remarkable peculiarity as distinguishable from 
 the human hand, is the smallness of the thumb ; 
 it extends no further than to the root of the 
 fingers. On the length, strength, free lateral 
 motion, and perfect mobility of the thumb, 
 depends the power of the human hand. The 
 thumb is called pollex, because of its strength ; 
 and that strength is necessary to the power of 
 the hand, being equal to that of all th fingers. 
 Without the fleshy ball of the thumb, the power 
 of the fingers would avail nothing ; and accord- 
 ingly the large ball, formed by the muscles of the 
 thumb, is the distinguishing character of the 
 human hand, and especially of that of an expert 
 workman.* 
 
 The loss of the thumb almost amounts to the 
 loss of the hand, and were it to happen in both 
 hands, it would reduce a man to a miserable 
 dependence: or as Adoni bezek said of the 
 threescore and ten kings, the thumbs of whose 
 hands and of whose feet he had cut off, " they 
 " gather their meat under my table." 
 
 In a French book, intended to teach young 
 people philosophy, the pupil asks why the 
 fingers are not of equal length? The form of 
 the argument reminds us of the difficulty of 
 putting natural questions the fault of books of 
 
 * Albinus characterises the thumb as the lesser hand, the 
 assistant of the greater manusparva, majori adjutrix.
 
 116 GEOLOGY INDEBTED TO 
 
 dialogue. However, the master makes the 
 scholar grasp a ball of ivory, to shew him that 
 the points of the fingers are then equal ! It 
 would have been better had he closed the fingers 
 upon the palm, and then have asked whether 
 or not they corresponded. This difference in 
 the length of the fingers serves a thousand pur- 
 poses, adapting the hand and fingers, as in 
 holding a rod, a switch, a sword, a hammer, a 
 pen, or pencil, engraving tool, &c., in all which, 
 a secure hold and freedom of motion are admi- 
 rably combined. But we must defer this part 
 of our subject until we have shewn the applica- 
 tion of the muscles to the bones, and the appro- 
 priate structure of the ends of the fingers to 
 feeling. 
 
 In conclusion, what says Ray, " Some 
 " animals have horns, some have hoofs, some 
 " teeth, some talons, some claws, some spurs 
 " and beaks: man hath none of all these, but is 
 " weak and feeble, and sent unarmed into the 
 " world Why, a hand, with reason, to use it, 
 " supplies the use of all these." 
 
 In taking leave of this part of our subject, let 
 us mark the importance of these comparative 
 views of anatomy to the science of Geology. It 
 has been ingeniously and quaintly said that the 
 organized remains imbedded in the rocks, are as 
 the medals struck in commemoration of the 
 great revolutions which the earth has under-
 
 COMPARATIVE ANATOMY. 117 
 
 gone. Every one must have seen that the crust 
 of the earth is formed in strata or layers: and 
 very slight consideration leads also to the belief 
 that it has been subject to great convulsions as 
 well as to successive deposits or formations. 
 Each of these layers is to a certain degree dis- 
 tinct in the chemical composition, in the fracture 
 and external character, but chiefly in the nature 
 of the animal remains which are buried in it. 
 
 Of these strata, some are distinguished by 
 containing the bones of large animals : and it is 
 by attending to the forms and processes of these 
 bones, that by far the most interesting conclu- 
 sions, in the whole range of this new science, 
 may be drawn. A very short account of the 
 successive deposits, forming the different strata, 
 will serve to illustrate the importance of the 
 anatomy of the animals which have the true 
 bony skeleton, to the geologist. The last grand 
 revolution has formed a surface to the earth, in 
 which strata, of every condition, have been ex- 
 posed. And indeed, we might say that such 
 exposure, by laying open the riches of the earth 
 as well as furnishing the mixed soil for vegeta- 
 tion, has been the end of this revolution. At all 
 events, the variety of objects disclosed on the 
 surface tends to confound the enquirer: and, 
 therefore, we must shortly recapitulate what has 
 been discovered by the investigations of scien- 
 tific and ingenious men in our time. 
 
 Without hazarding conjectures on the eleva-
 
 1 18 GEOLOGY INDEBTED TO 
 
 tion or production of the " primitive rocks," we 
 have at present only to notice the stratifications 
 superimposed. Of these, the most striking and 
 the most difficult to reconcile to theory, are the 
 strata of coal : but we pass over them as con- 
 taining no animal remains in which the know- 
 ledge of the anatomy of the vertebrata can be of 
 use. On the supposition that these beds of coal 
 are vegetable productions, we might expect to 
 find the remains of terrestrial animals within 
 them: but it is conjectured that the vegetables 
 which compose them, were not such as we are now 
 familiar with, and that the land where they grew 
 did not form a suitable habitation for animals 
 corresponding with those of the present epoch. 
 
 Above the beds of coal, are strata, regular, 
 well ascertained, and interesting as indicating 
 the presence of the coal beneath. The next 
 remarkable stratifications above them come to 
 be connected with our subject ; because they 
 contain the remains of gigantic animals, with a 
 regular skeleton on the system of the vertebrata. 
 
 Some of the oviparous quadrupeds, here al- 
 luded to, are estimated to have been eighty feet 
 in length.* But although their skeletons were 
 
 * The Megalosaurus, discovered by Professor Buckland in 
 Oxfordshire, is supposed to have been about seventy feet in length. 
 The Iguanadon, an herbivorous masticating reptile, first discover- 
 ed by Mr. Mantell in the Wealden beds, in Sussex, is computed 
 to have been seventy or eighty feet in its entire length, its tail 
 being fifty feet, its height nine feet, its hind foot six feet and a 
 half, and its body about the same thickness as the elephant's.
 
 COMPARATIVE ANATOMY. 119 
 
 formed on the plan, if we may thus express it, 
 of quadrupeds, the extremities of many of them 
 were more paddles than feet : * and we conclude 
 that they were capable of dragging their huge 
 bulk on the land, because the structure of their 
 skeletons proves that they were oviparous and 
 breathed the atmosphere. Some of them had a 
 conformation in their extremities, resembling 
 that of our present oviparous quadrupeds, to 
 enable them to walk or crawl on slimy ground; 
 and judging by the habits of these, as the croco- 
 dile, gavial, alligator, and cayman, certain spe- 
 cies of which were among them, they lived in still 
 water, with muddy bottom, retreating under the 
 mud, and projecting their snouts between the 
 aquatic plants, to breathe : and they must have 
 been prolific to an extraordinary degree, as they 
 had not their enemies, the vulture and the ich- 
 neumon, which destroy multitudes of the eggs of 
 these creatures of the present day. Others seem 
 to have had their skins extended on their ante- 
 rior extremities, t if not to provide a power of 
 flight, at least to allow them to drop in safety 
 Yrom the elevations which they might have crept 
 to. 
 
 The Hylseosaurus, the last discovered of these huge animals in 
 the same beds, and 'supposed by Mr. Man tell to have been a rep- 
 tile intermediate between the crocodiles and the lizards, is esti- 
 mated to have been about thirty feet in length. 
 
 * See page 114, and also the Appendix. 
 
 t The Pterodactyles, see page 83.
 
 120 GEOLOGY INDEBTED TO 
 
 Stratified rocks, composed of lime, clay, or 
 sandstone, under the denominations of lias, 
 oolite, Wealden or Sussex beds, Stones-field 
 slate, &c., are visible in the south of England, 
 and extend to many parts of Europe: and 
 these strata contain a great variety of those 
 oviparous reptiles. There is every appearance 
 of these deposits having been submerged and 
 deeply buried in the ocean : from which thick 
 beds of chalk have been deposited over them. 
 Above the chalk, again, are to be found a series 
 of stratified rocks, implying a new condition. 
 
 The lowest layer of this " tertiary formation" 
 is sometimes called the product of the Paloeo- 
 therian period : during its deposit, animals of a 
 distinct creation, the species of which cannot be 
 identified with those imbedded in the strata 
 under the chalk, are found. Here, for the first 
 time, there was a condition of the earth suited 
 for terrestrial animals, which retired under the 
 shade of woods and gave suck, the mammalia. 
 Yet it is remarkable, that in this, the lowest 
 stratification of the tertiary formation, the 
 animals of the class mammalia only approached 
 to the condition of those which are now alive : 
 we find the remains only of such as are now 
 extinct. 
 
 When the layers forming the tertiary beds are 
 examined in succession upwards, they are still 
 distinguishable by their organic products: and
 
 COMPARATIVE ANATOMY. 121 
 
 as we approach the surface, if theory has not 
 quite deceived us, there are fewer remains of the 
 extinct quadrupeds, and more numerous speci- 
 mens of such as now inhabit the earth. We find 
 in the different strata the bones of the mam- 
 moth, the megatherium, the elephant, the tapir, 
 the rhinoceros, the hippopotamus, the stag, the 
 ox, the horse, and with them the skeletons of 
 their natural enemies of the feline tribe, and the 
 bear and the hyaena, the bones of which prove 
 them to have been of greater strength and size 
 than those that are now alive. 
 
 Over the earth's surface, as thus formed, there 
 are evidences that a deluge has swept with in- 
 conceivable power, brushing off the superficial 
 strata, rolling immense rocks, and depositing 
 the debris, so as to fill chasms, form new accu- 
 mulations, and once more to change the whole 
 character of the earth's surface.* It was then 
 that it assumed its present confines of land and 
 sea, and that the valleys and the courses of rivers 
 were determined. Out of these convulsions and 
 successive revolutions has come that condition 
 of the world which we now enjoy, and, as I shall 
 have occasion to repeat, no previous state of the 
 earth's surface would have been suitable to our 
 constitution. 
 
 The waters as they flow to the ocean, and as 
 
 * See Reliquiae Diluvianae, by Professor Buckland.
 
 122 GEOLOGY INDEBTED TO 
 
 they are there met by tides and currents, accu- 
 mulate mud, gravel, and the remains of animals 
 of the species which now exist: and the deposits 
 which have thus taken place are distinguished 
 from those produced by the grand revolutions 
 which preceded, by the term ' alluvium.' 
 
 My admiration of the labours of our geologists 
 partakes of a feeling of gratitude. But yet 
 there is something in the subject which leads 
 the devoted student to be too ambitious, and to 
 frame theories almost too comprehensive. It is 
 not enough for the geologist to say that, after 
 all, the changes on the earth's surface which he 
 describes as having taken place, are not greater, 
 in comparison with the size of the earth, than 
 the cracks in the varnish are to the globe that 
 stands on the table. But it has been part of our 
 object to show that the features of our globe, 
 and the phenomena around us, are suited, and 
 intended, to excite the faculties and imagina- 
 tion. Accordingly, when the mineralogist ex- 
 tends his survey from the mountains over exten- 
 sive plains, and looks down into the ravines and 
 valleys, and persuades himself that he can say 
 when and how they have been formed, he is 
 tempted to indulge in an enthusiasm which can 
 have its merit only with the poet. 
 
 Wonderful improvements have indeed been 
 made in this science by our countrymen who 
 have associated themselves for this purpose.
 
 COMPARATIVE ANATOMY. 123 
 
 Buckland, Conybeare, and Mantell, are espe- 
 cially distinguished for the discovery of these 
 large Saurian reptiles; whilst other geologists 
 have exerted their genius and industry with 
 equal effect in different departments. But it is 
 in contemplating the labours of Cuvier, that we 
 have the earliest and the best proofs of the 
 importance of comparative anatomy, in giving 
 extraordinary interest to this science. In him 
 there was combined an attention to minute things 
 and a power of generalizing, highly charac- 
 teristic of genius. Years had been passed in 
 accumulating the animal remains from the quar- 
 ries round Paris; and out of this heap, which lay 
 as confused as if the bones had been washed to 
 his feet by a torrent, he was enabled, by follow- 
 ing the principle which the early part of this 
 chapter has shown to prevail the co-existence 
 of the parts of the skeleton to put together the 
 separate members, to build up the skeletons of 
 extinct animals anew, and to present them to us 
 with a precision which we could only have ex- 
 pected from the dissection of the recent animals.
 
 I --'I 
 
 CHAPTER IV. 
 
 Of the Muscles of the Arm and Hand their 
 Vital Action their Mechanical Adaptation to 
 the Motions of the Hand and Fingers Form 
 of the Human Hand. 
 
 THE muscle of the body is that fleshy part, with 
 which every one is familiar. It consists of fibres 
 which lie parallel to each other. This fibrous, 
 or filamentous part, has a living endowment, a 
 power of contraction and relaxation, termed 
 irritability. A single muscle is formed of some 
 millions of these fibres combined together, having 
 the same point of attachment or origin, and con- 
 centrating in a rope or tendon, which is fixed to 
 a moveable part, called its insertion. We may 
 demonstrate upwards of fifty muscles of the arm 
 and hand, all of which must consent to the 
 simplest action ; but this gives an imperfect view 
 of the extent of the relation of parts which is 
 necessary to every act of volition. We are most 
 sensible of this combination in the muscles, when 
 inflammation has seized any of the great joints 
 of the body : for even when in bed, every motion 
 of an extremity gives pain, through the necessity
 
 MUSCLE& OF THE ARM AND HAND. 125 
 
 of a corresponding movement in the trunk. 
 When we stand, we cannot raise or extend the 
 arm without a new position of the body, and a 
 poising of it, through the action of a hundred 
 muscles. 
 
 ON THE ACTION OF THE MUSCLES OF THE ARM. 
 
 We shall consider this subject under two 
 heads ; in the first, we shall give examples of 
 the living property of the muscles ; and then of 
 the mechanical contrivances, in their form and 
 application . In all that regards the muscles, we 
 see the most bountiful supply of power commen- 
 surate to the object, but never any thing in the 
 least degree superabundant. If the limb is to be 
 moved by bringing a muscle, or a set of muscles 
 into action, the power is not given in that excess 
 which would enable them to overcome their 
 opponents ; but the property of action is with- 
 drawn from the opponents ; they become relaxed, 
 and the muscles, which are in a state of contrac- 
 tion, perform their office with comparative ease. 
 A stationary condition of the limb results from a 
 balanced but regulated action of all the muscles ; 
 which condition may be called their tone. If, 
 in an experiment, a weight be attached to the 
 tendon of an extensor muscle, it will draw out 
 that muscle to a certain degree, until its tone or 
 permanent state resists the weight : but if the 
 
 B. Q
 
 126 OF THE MUSCLES OF 
 
 flexor muscle be now excited, this being the 
 natural opponent of the extensor, the weight will 
 fall, by the relaxation of the extensor. So that 
 the motion of a limb implies an active state or a 
 change in both classes of muscles, the one to 
 contract, the other to relax ; and the will in- 
 fluences both classes. Were it not so regulated, 
 instead of the natural, easy, and elegant motions 
 of the frame, the attempt at action would exhibit 
 the body convulsed, or, as the physicians term 
 it, in clonic spasms. The similitude of the two 
 sawyers, mentioned by Paley, gives but an im- 
 perfect idea of the adjustment of the two classes 
 of muscles. When two men are sawing a log of 
 wood, they pull alternately, and when the one is 
 pulling, the other resigns all exertion. But this 
 is not the condition of the muscles the relaxing 
 muscle does not give up all effort, like a loose 
 rope, but is controlled in its yielding, with as 
 fine a sense or adjustment, as is the action of the 
 contracting muscles. Nothing appears to us 
 more simple than raising the arm, or pointing 
 with the finger ; yet in that single act, not only 
 are innumerable muscles put into activity, and 
 as many thrown out of action, but both the 
 relaxing and the contracting muscles are con- 
 trolled or adjusted with the utmost precision 
 though in opposite states and under the same 
 act of volition. 
 
 By such considerations, we are prepared to 
 admire the faculty which shall combine a hun-
 
 THE ARM AND HAND. 127 
 
 dred muscles so as to produce a change of pos- 
 ture or action of the body ; and we now perceive 
 that the power taken from one class of our mus- 
 cles, may be considered as if it were bestowed 
 on the other ; so that the property of life, which 
 we call the irritability, or action of a muscle, is 
 upon the whole, less exhausted than would be 
 the case on any other supposition. 
 
 As to the second head, our demonstration is 
 of an easier kind. We have said that nature 
 bestows abundantly, but not superfluously ; a 
 truth evinced in the arrangement of the muscles. 
 All the muscles of the limbs have their fibres 
 running in an oblique direction, thus A. being 
 the tendinous origin of a muscle, and B. the 
 tendinous insertion, the fleshy fibres run ob- 
 liquely between these two tendons. 
 
 The fibre acting thus obliquely loses power, but 
 gains the property of pulling what is attached 
 to its further extremity through a greater space, 
 while it contracts ; and consequently the velo- 
 city is increased. This mechanical arrange- 
 ment is intelligible on the law, that velocity of 
 motion through space, is equal to power or 
 weight. Here in the muscle, there is a resig- 
 nation of power to obtain velocity of motion.
 
 128 OF THE MUSCLES OF 
 
 The same effect is produced by the manner in 
 which the tendons of the muscles run over the 
 joints. They would act more powerfully, if they 
 went in a straight line to the toes or tips of the 
 fingers : but by being laced down in sheaths, 
 they move the toes and fingers with a velocity 
 proportioned to their loss of power. 
 
 Let us see how far this corresponds with other 
 mechanical contrivances. A certain power of 
 wind or water being obtained, the machinery is 
 moved ; but it is desired to give a blow, with a 
 velocity far greater than the motion of the water 
 or the turning of the wheels. For this purpose 
 a fly-wheel is put on, the spokes of which may 
 be considered as long levers. The wheel moves 
 very slowly, at first ; but being once in motion, 
 each impulse accelerates it with more and more 
 facility ; at length, it acquires a rapidity, and a 
 centrifugal force which nothing can equal in its 
 effects, but the explosion of gunpowder. The 
 mechanist not having calculated the power of 
 accelerated motion in a heavy wheel, has seen 
 his machinery split and burst up, and the walls 
 of the house blown out as by the bursting of a 
 bomb-shell. A body at rest receives an im- 
 pulse from another, which puts it into motion- 
 it receives a second blow ; now this second blow 
 has much greater effect than the first for the 
 power of the first was exhausted in changing the 
 body from a state of rest to that of motion but 
 being in motion when it receives the second
 
 THE ARM AND HAND. 129 
 
 blow, the whole power is bestowed on the accele- 
 ration of its motion ; and so on, by the third and 
 fourth blows, until the body moves with a velo- 
 city, equal to that of the body from which the 
 impulse is originally given. The slight blow 
 given to a boy's hoop is sufficient to keep it run- 
 ning ; and just so the fly-wheel of a machine is 
 kept in rapid action by a succession of impulses, 
 each of which would hardly put it in motion. 
 If we attempt to stop the wheel, it will give a 
 blow in which a hundred lesser impulses are 
 combined and multiplied. 
 
 There is, in the machinery of the animal 
 "body, in a lesser degree, the same interchange 
 of velocity and force. When a man strikes 
 with a hammer, the muscle near the shoulder,* 
 
 * A. The scapula, or shoulder blade ; B. the humerus, or arm- 
 bone; c. the deltoid muscle of the shoulder, arising from the 
 shoulder-blade and clavicle, and inserted into the arm-bone; D. 
 a muscle which draws the arm down, as in striking with a sword 
 or hammer.
 
 130 OF THE MUSCLES OF 
 
 c., acts upon the humerus, B., in raising the ex- 
 tended lever of the arm and hammer, with every 
 possible disadvantage, seeing that it is inserted 
 or attached so near the centre of motion in the 
 shoulder joint. But the loss of power is restored 
 in another form. What the muscle D. loses by 
 the mode of its insertion, is made up in the 
 velocity communicated to the hammer ; for in 
 descending through a large space, it accumulates 
 velocity, and velocity is equal to force. The 
 advantage of the rapid descent of a heavy body 
 is, that a smart blow is given, and an effect pro- 
 duced which the combined power of all the 
 muscles, without this mechanical distribution of 
 force, could not accomplish. This is, in truth, 
 similar to the operation of the fly wheel, by 
 which the gradual motion of an engine is accu- 
 mulated in a point of time, and a blow is struck 
 capable of crushing or of stamping a piece of 
 gold or silver. In what respect does the 
 mechanism of the arm differ from the engine 
 with which the printer throws off his sheet ? 
 
 Here is a lever with a heavy ball at the end ; in
 
 THE ARM AND HAND. 131 
 
 proportion to its weight, it is difficult to be put 
 in motion. The printer, therefore, takes hold of 
 the lever near the ball, at A. Were he to con- 
 tinue pulling at that part of the lever, he would 
 give to the ball no more velocity than that of his 
 hand ; but having put the ball into motion, he 
 slips his hand down the lever to B. He could 
 not have moved the weight, had he applied his 
 hand here at first ; but it being now in motion, 
 the whole strength of his arm is given to the 
 lever at B., whilst the velocity of the great 
 weight at the further end is accelerated. Thus 
 the weight and the velocity being combined, the 
 impulse given to the screw is much greater than 
 if he had continued to pull upon the further end 
 of the lever at A. 
 
 If we now turn our eye to the diagram (page 
 129), we shall understand that the muscle c. 
 raises the long lever of the arm at a disad- 
 vantage, or very slowly ; but the arm being 
 moved, that motion is rapidly increased by 
 each successive impulse from the muscle ; 
 and, of course, the velocity at the further ex- 
 tremity is more rapid than at the insertion of 
 the tendon. 
 
 Again, if we consider the action of the muscle 
 D. in pulling down the arm, as in giving a back 
 stroke with the sword, we have the combination 
 of two powers, weight and muscular effort. 
 When the hammer descends, the rapidity is 
 increased by the mere effect of gravity ; but
 
 132 OF THE MUSCLES OF 
 
 when the action of the muscle is conjoined, the 
 two forces, progressively increasing, greatly 
 augment the velocity of the descent. 
 
 The same interchange of power for velocity, 
 which takes place in the arm, adapts a man's 
 hand and fingers to a thousand arts, requiring 
 quick or lively motions. The fingers of a lady, 
 playing on the pianoforte, or of the compositor 
 with his types, are instances of the advantage 
 gained by this sacrifice of force for velocity of 
 movement. The spring of the foot and toe is 
 bestowed in the same manner, and gives elasticity 
 and rapidity in running, dancing, and leaping. 
 
 The motions of the fingers do not result merely 
 from the action of the large muscles which lie 
 on the fore-arm : these are for the more power- 
 ful efforts; but in the palm of the hand, and be- 
 tween the metacarpal bones, there are small 
 muscles, (lumbricales and inter ossei) which per- 
 form the finer motions, expanding the fin- 
 gers, and moving them in every direction with 
 quickness and delicacy. These small muscles, 
 attached to the near extremities of the bones 
 of the fingers where they form the first joint, 
 being inserted near the centre of motion, move 
 the ends of the fingers with very great velocity. 
 They are the organs which give the hand the 
 power of spinning, weaving, engraving ; and as 
 they produce the quick motions of the musi- 
 cian's fingers they are called by the anatomistr 
 fidiciiiales.
 
 THE ARM AND HAND, 133 
 
 But there is another use for certain small 
 muscles in the hand. The combined strength 
 of all the muscles, in grasping, must be very 
 great: indeed, the power is exhibited when we 
 see a sailor hanging by a rope, and raising his 
 whole body with one arm. What then must be 
 the pressure upon the hand ? It would be too 
 much for the texture even of bones and tendons, 
 arid certainly, for the blood vessels and nerves, 
 were not the palms of the hands, the inside of 
 the fingers and their tips, guarded by cushions. 
 The elastic pad in the foot of the horse and 
 camel is not a whit more appropriate than the 
 fine elastic texture of the hand. To add to this 
 purely passive defence there is a muscle, which 
 runs across the palm, and more especially sup- 
 ports the cushion on the inner or ulnar edge : it 
 acts powerfully as we grasp ; and it is this 
 muscle which, raising the edge of the palm, hol- 
 lows it, and adapts it to lave water, forming the 
 cup of Diogenes. 
 
 Whilst the cushions on the ends of the fingers 
 defend them in the powerful actions of the hand, 
 we shall presently see that they are useful in 
 subservience to the nerves of touch ; conferring a 
 power of receiving impressions, which the ut- 
 most delicacy of the nerves themselves could not 
 bestow. 
 
 After the many illustrations from mechanics 
 which we have offered, the muscular power itself 
 
 B. R
 
 134 MECHANICAL PROPERTIES 
 
 must be a subject of surprise and admiration. 
 Gravity, the running of water, the expansion 
 and condensation of steam, the production of 
 gases, the spring or elasticity of material, or all 
 these combined, could not have answered the 
 varied offices performed by this one property of 
 life possessed by the muscles. The irritable 
 and contractile fibre, matter which, chemically 
 considered, does not differ from the fibrine of 
 the blood, being endowed with this property of 
 contraction, and adapted with " mechanical 
 ingenuity," fulfils a thousand distinct purposes, 
 in volition, breathing, speaking, in digestion, 
 assimilation, circulation ; and in all these it is 
 modified to the wants and condition of every 
 class of animals. 
 
 From what the reader already understands of 
 the conformity which subsists among all the 
 parts of an animal body, he will readily com- 
 prehend that there is a perfect relation between 
 the bones and the muscles : that as the bones 
 change, and exhibit a variety in their size, 
 relative position, and articulations, so there is 
 an adaptation of the muscles. Accordingly, 
 we sometimes find the muscles separated into 
 smaller, and sometimes consolidated into more 
 powerful masses. 
 
 The demonstration to the anatomical student 
 of the muscles of the human hand and arm, be- 
 comes the test of his master's perfection as a
 
 OF THE MUSCLES OF THE ARM. 135 
 
 teacher. Nothing is more uninteresting, tedious, 
 and difficult to attend to, than the demonstration 
 of the muscles of the arm, when they are taken 
 successively, as they present themselves ; but 
 when they are taught with lucid arrangement, 
 according to the motions performed by them, it 
 is positively agreeable to find how much interest 
 may be given to the subject. 
 
 It would be foreign to the object of this work 
 to introduce such demonstrations here. 
 
 Yet it is very remarkable that the muscles of 
 the arm and hand should resemble so closely the 
 muscles of the fore extremity of the lion, for 
 example. I have added a sketch of the muscles 
 of the lion's fore leg and paw ; in which we see 
 that the shape bears a great resemblance to the 
 fore-arm of man. The flexors, extensors, pro- 
 nators, and supinators are, in the brute, exactly 
 in the same place, and bear all the relations 
 which the student of anatomy is taught to ob- 
 serve with so much interest in the human arm. 
 This example is sufficient to show how accu- 
 rately the comparative anatomy of the muscles 
 conforms to that of the bones ; and that in pro- 
 portion as the bones of the extremity resemble, 
 in shape and power of motion, those of the 
 human arm, so do the muscles another proof of 
 the great extent of the system of relations estab- 
 lished in the animal frame. 
 
 There is one circumstance more which should
 
 l.'3<> CIRCULATION OF THE BLOOD 
 
 not he omitted in the comparative anatomy of 
 these muscles, as it exhibits another instance of 
 
 conformity in their structure to the offices which 
 they have to perform. We have just stated that
 
 THROUGH THE MUSCLES. 137 
 
 the power of contraction is a vital property. 
 The continued action of a muscle, therefore, 
 exhausts the vitality ; and to support that action, 
 when it is inordinate, there must be a more 
 than usual provision for the supply of this living 
 power, viz : a means of increasing or main- 
 taining the circulation of the blood, which is the 
 source of all vital power. 
 
 In the loris tardigradus* it has been observed 
 that the axillary and femoral arteries, the great 
 arteries of the anterior and posterior extremities, 
 have this peculiarity that the main vessel is 
 sub-divided into a number of equal-sized cylin- 
 ders, which again unite to form a single trunk 
 previous to the distribution of its branches to 
 the muscles, t It has been argued that this 
 peculiarity, as it produces a retardation of the 
 blood, is adapted to the slow motion of the 
 animal. I believe it to be a provision for long 
 continued action ; because the animals which 
 possess it, are not more remarkable for the 
 slowness of their progression than for the tena- 
 city of their hold : the extremities are long and 
 the muscles powerful, either for sustaining the 
 animal by grasping the branches of trees, or for 
 digging ; but surely the strength of the muscles 
 cannot be produced by retardation of the cir- 
 
 * See the Appendix, Division I. Quadrumana. 
 t There is some doubt as to the reunion of the vessels. 
 Ji. S
 
 138 SUPERIORITY OF THE 
 
 dilation, on the principle, universally admitted, 
 that the expenditure of arterial blood is in pro- 
 portion to the vital force employed. 
 
 Buffon tried to make a dog amphibious, by 
 immersing the puppy before it had breathed, in 
 tepid water. One of our own physiologists 
 thought it possible to make a tardigrade animal 
 out of a vivacious spaniel by putting ligatures 
 upon the arteries which go to its limbs, and 
 forcing the blood to take a circuitous course, by 
 numerous channels, to the muscles. We need 
 hardly say that these experiments failed. They 
 were undertaken in a misconception of the living 
 properties ; which are more finely adjusted than 
 any thing to be seen in the mere mechanism of 
 the body. Every muscle of the body has its pre- 
 scribed mode of action, from the unwearied irri- 
 tability of the heart to the effort of the muscle 
 which guides the pen. Some are ever in action 
 with but short intervals ; others act in regular 
 succession : some are under the will, others with- 
 drawn from it; some act quickly as the heart, 
 others act slowly as the stomach ; but these are 
 original endowments, and do not result from the 
 force or languor of the circulation of the part. 
 
 Were the arteries of the living body like rigid 
 tubes, and the laws of the circulation the same 
 as those of hydraulics, a subdivided and tortuous 
 artery would certainly be the means of retarding 
 the circulation. But it is impossible to believe
 
 RIGHT HAND OVER THE LEFT. 139 
 
 that the circulation of the blood can be performed 
 according to the laws which govern the flow of 
 water in dead tubes. The artery is dilatable ; 
 it contracts with a vital force; and both the 
 dilatability and the contractility of arteries are 
 subject to the influence of the living principle. 
 When, therefore, the artery of a limb is divided 
 into four or five vessels, and these are tortuous, 
 as in the sloths, the result is a greater capacity 
 of dilatation, and a greater power of contraction ; 
 and these being vital operations, are subject to 
 be influenced and adjusted according to the 
 necessity for the increase or diminution of the 
 circulation. If such a peculiarity in the form of 
 the vessels in the extremities of these animals, 
 retards the blood, it can only be during repose; 
 for, on excitement, so far from retarding, it must 
 bestow a remarkable power of acceleration. I 
 conclude, therefore, that this variety of distribu- 
 tion in the arteries is a provision for occasional 
 great activity in the muscles of the limb, and for 
 forcing the blood into contact with the fibres, 
 notwithstanding their long continued action and 
 rigidity. 
 
 We have seen, in the preceding chapter, that 
 the same organ, which moves at one time as 
 slowly as the hand of a watch, at another acts 
 with extreme rapidity : consequently, we can 
 not admit the inference that the tortuous and sub- 
 divided artery is a provision for languid motions.
 
 140 SUPERIORITY OF THE 
 
 In speaking of the arteries which go to the 
 hand, it may be expected that we should touch 
 on a subject, which has been formerly a good 
 deal discussed, whether the properties of the 
 right hand, in comparison with those of the left, 
 depend on the course of the arteries to it: for 
 it is affirmed that the trunk of the artery going 
 to the right arm, passes off from the heart so as 
 to admit the blood directly and more forcibly 
 into the small vessels of the arm. This is 
 assigning a cause which is unequal to the effect, 
 and presenting, altogether, too confined a view 
 of the subject : it is a participation in the com- 
 mon error of seeking in the mechanism the cause 
 of phenomena which have a deeper source. 
 
 For the conveniences of life, and to make us 
 prompt and dexterous, it is pretty evident that 
 there ought to be no hesitation which hand is to 
 be used, or which foot is to be put forward ; nor 
 is there, in fact, any such indecision. Is this 
 taught, or have we this readiness given to us by 
 nature ? It must be observed, at the same time, 
 that there is a distinction in the whole right side 
 of the body, and that the left side is not only 
 the weaker, in regard to muscular strength, but 
 also in its vital or constitutional properties. The 
 developeinent of the organs of action and motion 
 is greatest upon the right side, as may at any 
 time be ascertained by measurement, or the 
 testimony of the tailor or shoemaker ; certainly,
 
 RIGHT HAND OVER THE LEFT., 141 
 
 this superiority may be said to result from the 
 more frequent exertion of the right hand ; but 
 the peculiarity extends to the constitution also ; 
 and disease attacks the left extremities more 
 frequently than the right. In opera dancers, 
 we may see that the most difficult feats are per- 
 formed by the right foot. But their preparatory 
 exercises better evince the natural weakness of 
 the left limb, since these performers are made 
 to give double practice to this limb, in order to 
 avoid awkwardness in the public exhibition ; for 
 if these exercises be neglected, an ungraceful 
 preference will be given to the right side. In 
 walking behind a person, it is very seldom that 
 we see an equalized motion of the body ; and if 
 we look to the left foot, we shall find that the 
 tread is not so firm upon it, that the toe is not so 
 much turned out as in the right, and that a 
 greater push is made with it. From the pecu- 
 liar form of woman, and the elasticity of her 
 step resulting more from the motion of the 
 ankle than of the haunches, the defect of the 
 left foot when it exists, is more apparent in her 
 gait. No boy hops upon his left foot, unless he 
 be left handed. The horseman puts the left 
 foot in the stirrup and springs from the right. 
 We think we may conclude, that every thing 
 being adapted, in the conveniences of life, to the 
 right hand, as for example the direction of the 
 worm of the screw or of the cutting end of the
 
 142 SUPERIORITY OF THE RIGHT HAND. 
 
 augur, is not arbitrary, but is related to a natural 
 endowment of the body. He who is left handed 
 is most sensible to the advantages of this adap- 
 tation, from the opening of the parlour door to 
 the opening of a pen-knife. On the whole, the 
 preference of the right hand is not the effect of 
 habit, but is a natural provision, and is bestowed 
 for a very obvious purpose : and the property 
 does not depend on the peculiar distribution of 
 the arteries of the arm but the preference is 
 given to the right foot, as well as to the right 
 hand.
 
 143 
 
 CHAPTER V. 
 
 THE SUBSTITUTION OF OTHER ORGANS FOR THE 
 HAND. 
 
 AFTER having examined the manner in which 
 one instrument, the hand, is modified and 
 adapted to a variety of purposes in different 
 animals, there remains only this mode of eluci- 
 dation that we contrast it with its imperfect 
 substitutes in other creatures. I might, indeed, 
 have shown in the insect tribes the most curious 
 examples of instruments for similar purposes 
 with the hand and fingers of man ; but I have 
 intentionally confined this inquiry to the higher 
 classes of animals. 
 
 The habits of some fishes require that they 
 should cling firmly to the rocks or to whatever 
 presents to them. Their locomotive powers are 
 perfect ; but how are they to become stationary 
 in the tide or the stream ? I have often thought 
 it wonderful that the salmon or the trout, for 
 example, should keep its place, night and day, 
 in the rapid current. In the sea, there are some 
 fishes especially provided with means of clinging 
 to the rocks. The lump-fish, cyclopterus lumpus,
 
 J44 SUBSTITUTES FOR THE HAND. 
 
 fastens itself by an apparatus which is on the 
 lower part of its body. The sucking fish, remora, 
 has a similar provision on its back. It attaches 
 itself to the surface of the shark and to whatever 
 is afloat; and, of course, to the bottoms of ships. 
 The ancients believed it capable of stopping a 
 ship under sail, and Pliny, therefore, called it 
 remora. We must admire the means by which 
 these fishes retain their proper position in the 
 water, without clinging by their fins or teeth, 
 and while they are free for such efforts as may 
 enable them* to seize their food. The appa- 
 ratus by which they attach themselves resembles 
 a boy's sucker : the organ being pressed against 
 the surface to which the creature is to be fixed, 
 the centre is drawn by muscles in the same 
 manner that the sucker is drawn with the cord, 
 and thus a vacuum is made. 
 
 Dr. Shaw tells us, that on throwing a fish of 
 
 * In the Mollusca and Zoophytes we find many instances of 
 the animal holding on against the force of tide or current. The 
 Actiniee fix themselves to rocks and shells ; and some, as the sea 
 carnation, hang suspended from the lower surface of projecting 
 rocks, resembling the calyx of a flower. By the elongation of 
 their tentacula, they expand and blow out like a flower; but 
 instead of petals, these are prehensile instruments by which they 
 draw whatever food floats near them into their stomachs. The 
 byssus of the muscle is a set of filaments which retains the shell 
 at anchor, and prevents it drifting or rolling with the tide : these 
 filaments are the secretion of a gland ; and whilst they are fixed 
 to the rock, the gland retains the hold at their other ends. The 
 shell of the oyster is itself cemented to the rock.
 
 SUBSTITUTES FOR THE HAND. 145 
 
 the species cyclopterus lumpus into a pail of 
 water, it fixed itself so firmly to the bottom, that 
 by taking hold of the tail, he lifted up the pail, 
 although it contained some gallons of water. 
 
 In the cuttle-fish we see a modification of this 
 apparatus: the suckers are ranged along their 
 feelers or arms, and become instruments of pre- 
 hension and of locomotion. They are capable of 
 being turned in all directions, either to fix the 
 animal or to drag it from place to place. In the 
 Indian seas, these creatures become truly terrific 
 from the length of their arms, which extend to 
 eight or nine fathoms, and from the firmness 
 with which they cling. 
 
 There is another fish, which from its name 
 we should expect to perform strange antics; it 
 is called harlequin angler.* Its appearance is 
 
 * Lophius Histrio, from a Greek word that has reference to 
 the process which floats from the head, like a streamer or pennant. 
 
 B. T
 
 14(J SUBSTITUTES FOR THE HAND. 
 
 grotesque and singular; the pectoral fins re- 
 semble short arms, and are palmated at their 
 tips.* M. Renau, in his history of fishes, affirms 
 that he knew an individual of this species ; and 
 the expression is not so incorrect, since he saw 
 it for three days out of the water, walking about 
 the house in the manner of a dog. The circum- 
 stance of its walking out of the water has some 
 interest, as showing relations between organs 
 which are apparently the least connected. The 
 fact of this fish living out of the water is 
 doubted ; but the form of its branchial organs, 
 or organs for breathing, inclines me to believe 
 it; and its habits require such a provision. In 
 this genus, the operculum, which covers the 
 gills, does not open to let the respired water 
 pass off freely behind, as in most fishes; but 
 the water is discharged by a small aperture 
 which, in Mr. Owen's opinion, is capable of 
 being closed by a sphincter muscle. The cavi- 
 ties in which the branchiae lie are large, and this 
 is, indeed, partly the reason of the monstrous 
 head of this fish. Thus, it has not only its fins 
 converted into feet, but its gill-covers into 
 pouches, capable of containing water, and of 
 permitting the function of the branchiae to pro- 
 ceed when the water is retired ; that is, when it 
 
 * Those fins have two bones in them like the radius and ulna ; 
 but Cuvier says that they are more strictly bones of the carpus.
 
 SUBSTITUTES FOll THE HAND. 147 
 
 lies in mud, or shallow pools ; for in such situa- 
 tions does the lophius find its food ; and it 
 angles for it in a very curious manner. 
 
 But there are other fishes that move out of the 
 water on dry land, and even ascend trees, with- 
 out being carried there by floods. The perca 
 scandens, by means of the spines of its gill-covers, 
 and the spinous rays of its fins, climbs trees ; so 
 that Dr. Shaw calls it the climbing fish.* 
 
 All creatures which have their skins protected, 
 whether by feathers, or shells, or scales, have an 
 exquisite sense of touch in their mouth, or in the 
 appendages which hang from it. Fishes have 
 cirri which hang from their mouth; and these 
 are equivalent to the feelers or tentacula of 
 insects and Crustacea. The fishing lines of the 
 lophius piscatorius are examples of these pro- 
 cesses: and Pliny relates that this frog-like 
 fish, hiding in the mud, leaves the extremities of 
 these filaments visible ; which, from their re- 
 semblance to worms, entice the smaller fishes, 
 and they become the prey of their concealed 
 enemy. It is surprising how varied the means 
 are by which fishes obtain their food. The 
 chcetodon (bandouliere a bee) squirts water at 
 flies as they pass and brings them down. The 
 
 * The spines of the Echinus, or Sea Urchin, are moveable; they 
 assist in progression. They are directed towards an advancing 
 enemy! Although these spines may be effectual for their purpose, 
 they are the lowest or least perfect substitutes for the extremities.
 
 148 SUBSTITUTES FOR THE HAND. 
 
 scicena jaculatrix, according to Pallas, has a 
 similar power ; and the sparus insidiator catches 
 aquatic insects by the sudden projection of its 
 snout. It is affirmed by some naturalists that 
 the rays of the dorsal and anal fins, as in the 
 cordonnier of Martinique (zeus ciliaris, le ble- 
 pharis, Cuv.), are employed to grapple or coil 
 round the stems of plants and sustain the fish. 
 
 The several offices attributed to these processes 
 in fishes imply that they possess sensibility, if 
 not muscular power. 
 
 By anatomical investigation and experiment, 
 I, some years ago, discovered that the sensibility 
 of all the head, and of its various appendages, 
 resulted from one nerve only of the ten which 
 are enumerated as arising from the brain, and
 
 SUBSTITUTES FOR THE HAND. 149 
 
 are distributed within and around the head ; 
 and, pursuing the subject by the aid of com- 
 parative anatomy, I found that a nerve corres- 
 ponding to this, which is the fifth nerve in man, 
 served a similar purpose in all the lower animals. 
 In creatures which are covered with feathers or 
 scales, or protected by shell, this nerve be- 
 comes almost the sole organ of sensibility. It 
 is the developement of this nerve -which gives 
 sensibility to the cirri, which hang about the 
 mouths of fishes, and to the palpa of the cms- 
 tacea and insects. It is the same nerve which 
 supplies the tongue, and is the organ of its 
 exquisite sensibility to touch, as well as of taste. 
 In some animals, especially in the reptiles, the 
 tongue, by its length and mobility, becomes a 
 substitute for these external appendages. We 
 might have noticed before, that the tongue is an 
 organ of prehension as well as of touch. With 
 it the ox gathers in the herbage; and in the 
 giraffe, it is rather curious to observe that as the 
 whole frame of the animal is calculated to raise 
 the head to a great height, so is the tongue capa- 
 ble of projecting beyond the mouth to an extra- 
 ordinary extent, to wrap round and pull down 
 the extreme branches of trees. The whiskers of 
 the feline quadrupeds possess a fine sensibility 
 through branches of the fifth nerve, which enter 
 their roots. Birds have a high degree of sensi- 
 bility to touch in their mouths. In ducks, and 
 B. u
 
 150 SUBSTITUTES FOR THE HAND. 
 
 all that quaffer with their bills under water, the 
 sense is very fine, and we find, on dissection, 
 that a branch of the fifth nerve, remarkably 
 developed, is distributed on the upper mandible. 
 Animals feel in the whole of their external sur- 
 face ; and we may say that serpents, by coiling 
 themselves round a body, have the organ of 
 touch all over them. Still the fifth pair of nerves 
 in the head, or the nerve analogous to it, is the 
 main instrument of touch in the greater number 
 of animals where extremities are wanting. There 
 are organs varying in their conformation, some- 
 times delicate palpa, sometimes horny rods, and 
 these are often possessed of muscularity as well 
 as sensibility ; but to all, the sense of touch is 
 bestowed through a nerve corresponding with 
 the fifth pair, the nerve of the tongue and lips, 
 and of the muscles of the jaws in man. 
 
 But we may repeat, that, necessary as these 
 appendages and this sensibility are to the exis- 
 tence of these animals, their imperfections serve, 
 by contrast, to show how happily the different 
 properties are combined in the hand ; in which 
 we perceive the sensibilities to changes of tem- 
 perature, to touch, and to motion, united with a 
 facility in the joints of unfolding and moving in 
 every possible degree and direction, without 
 abruptness or angularity, and in a manner inimi- 
 table by any artifice of joints and levers.
 
 151 
 
 CHAPTER VI. 
 
 THE ARGUMENT PURSUED FROM THE COMPARATIVE 
 ANATOMY. THE ANIMAL SYSTEM, AND THE REVO- 
 LUTIONS IN THE SOLID MATERIAL OF IT. 
 
 So far as we have hitherto proceeded, by exa- 
 mining objects in comparative anatomy which 
 from their magnitude cannot be misunderstood, 
 we have been led to conclude that, independently 
 of the system of parts marvellously combined to 
 form the individual animal, there is another 
 more comprehensive system, which embraces 
 all animals ; and which exhibits a certain uni- 
 formity in the functions of life, however different 
 in form or bulk the creatures may be, or to 
 whatever condition of the globe they may have 
 been adapted. We have seen no accidental 
 deviation or deformity, but every change has 
 been for a purpose, and every part has had its 
 just relation. We have witnessed all the varie- 
 ties moulded to such a perfect accommodation, 
 and the alterations produced by such minute 
 degrees, that all notion of external and acci- 
 dental agency must be rejected. 
 
 We might carry our demonstration downward
 
 152 COMPARATIVE ANATOMY PURSUED. 
 
 through the lower classes of animals ; for exam- 
 ple, we might trace the feet of insects from their 
 most perfect or complex state, till they disap- 
 pear; or, observing the changes in another direc- 
 tion, we might follow out the same parts from 
 the smallest beginning to the most perfect condi- 
 tion of the member, where we see the thigh, leg, 
 and tarsus of the fly. We might distinguish 
 them at first as the fine cirri, like minute 
 bristles, which, on the bodies of worms take 
 slight hold of the surface over which they creep. 
 In the sea mouse, (aphrodita) we might notice 
 these bristles standing out from distinct mammil- 
 lary processes, which are furnished with appro- 
 priate muscles. Then in the myriapodes, the 
 first order of insects, we might see the same 
 " many feet," and each foot having a distinct 
 articulation. From that, we might pass to the 
 feet of those insects, where there is a thigh, leg, 
 and foot, with the most perfect system of flexors, 
 extensors, and adductor muscles, possessing, in 
 fine, all that we most admire in the human ana- 
 tomy. Nay, it is more curious to observe how 
 the feet of the true insects are again changed or 
 modified, taking new offices, the anterior feet 
 becoming feelers, organs of prehension, or hands. 
 When, with such an object, we view the delicate 
 and curiously adapted instruments of insects, we 
 must perceive that it would be easy to trace 
 almost every part through a succession of modi-
 
 THEORY OF ELEMENTAL PARTS. 153 
 
 fi cations. Among the vertebrata, we have seen 
 the hand become a wing or a fin ; so might we 
 trace the wings of insects. If we begin with a 
 fly, which has two delicate and perfect wings 
 incased and protected, we find that the covers 
 are raised to admit the expansion of the wings- 
 In another, the case becomes a wing ; and the 
 fly is characterised by four wings. Proceeding 
 to examine a third example, we shall discover 
 that this anterior wing is larger and more perfect 
 than the posterior : the fourth specimen has lost 
 the posterior wings, and has only two perfect 
 ones ; and if we continue the examination, the 
 next specimen will present an insect deprived of 
 wings altogether. These are not freaks of na- 
 ture, but new forms of the body ; new appen- 
 dages required for a different poising of the fly 
 in its flight. They are adaptations in that 
 regular series which we have observed to obtain 
 in the larger animals, and where the intention 
 can not be mistaken. A very natural question 
 will force itself upton us, how are those varieties 
 to be explained ? 
 
 The curious adaptation of a member to dif- 
 ferent offices and to different conditions of the 
 animal has led to a very extraordinary opinion 
 in the present day, that all animals consist of 
 the same elements. It would be just to say that 
 they consist of the same chemical elements, and 
 that they attract and assimilate matter by the
 
 154 THEORY OF 
 
 performance of the same vital functions, through 
 every species of animals, however different in 
 form and structure. But by the elements which 
 are now mentioned, the authors of this new 
 theory mean certain pieces which enter into 
 the structure of the body; and which they 
 suppose may be transposed and differently 
 arranged. They illustrate their views by the 
 analogy of the building materials of a house. 
 If these materials, they say, are exhausted in 
 the ornamental parts of the portico and ves- 
 tibule, there must be a proportionate limitation 
 of the apartments for the family. 
 
 This new theory has been brought forward 
 with the highest pretensions; the authors of it 
 have called upon us to mark the moment of its 
 conception as the commencement of a new aera ! 
 They speak of the " elective affinities of 
 organs," " the balancing of organs," " a new 
 principle of connection," and a " new theory of 
 analysis." The hypothesis essentially is this, 
 that when a part, which belongs to one animal, 
 is missed in another, we are to seek for it in 
 some neighbouring organ : and on such grounds 
 they affirm, that this surpasses all former systems 
 as a means of discovery. Now, the perfection 
 or aggrandizement of any one organ of an 
 animal is not attended with the curtailment or 
 proportional deficiency of any other. Perhaps, 
 the supporters of this theory dwell too much
 
 ELEMENTAL PARTS. 155 
 
 upon the bones; but even in them, we shall 
 show that the system is untenable. In the 
 meantime, we may ask, do additional parts con- 
 nected with the stomach, making it highly com- 
 plex, as in ruminating animals, shorten the in- 
 testinal canal, or make its form simpler? On 
 the contrary, is not a complex stomach neces- 
 sarily connected with a long and complicated 
 intestine? Does a complex intestinal canal 
 throughout all its course, render the solid viscera 
 which are in juxtaposition to it imperfect? Is 
 there any defect in them, because the organs of 
 digestion are perfect or complicated ? Does the 
 complex heart imply a more simple, or a more 
 perfect condition of the lungs ? In short, as 
 animals rise in the scale of existence, do we not 
 find that the systems of digestion, circulation, 
 respiration, and sensation bear ever a propor- 
 tional increase ? Is there any instance of an im- 
 provement in one organ thrusting another out of 
 its place, or diminishing its volume ? 
 
 As to the osseous system, were we to follow 
 these theorists into the very stronghold of their 
 position, the bones of the skull, where the real 
 intricacy of the parts allows them some scope for 
 their ingenuity, we might show how untenable 
 the principle is which they assume. But we 
 must confine ourselves to our own subject. 
 
 In the higher orders of the vertebrata, we find 
 that the bones of the shoulder perform a double
 
 150 THEORY OF 
 
 office; that they have an important share in the 
 act of respiration, whilst they are perfect as a 
 foundation for the extremity. Now, let us take 
 an instance where the mode of respiration of the 
 animal is inconsistent with what we may term 
 the original mechanism of the bones of the 
 shoulder. In the batrachian order, the ribs are 
 wanting : where then are we to look for them ? 
 Shall we follow a system which informs us that 
 when a bone is wanting in the cavity of the ear 
 we are to seek for it in the jaw ; yet, which, 
 shall leave us in the contemplation of this class 
 of animals deficient in thirty-two ribs, without 
 pointing out where they are to be found, or how 
 these elements are built up in other structures ? 
 If, on the contrary, we take the principle that 
 parts are formed or withdrawn, with a never 
 failing relation to the function which is to be 
 performed, we see that no sooner are the corn- 
 pages of the chest removed, and the shoulder 
 thus deprived of support, than the bones to 
 which the extremity is fixed are expanded and 
 varied, both in form and articulation, so as to 
 fulfil their main object of giving security and a 
 centre of motion to the arm. 
 
 With respect to the instance which we have 
 accidentally noticed of the mechanism of the 
 jaw in birds, and which is brought forward so 
 vauntingly as a proof of the excellence of the 
 theory, it does, indeed, prove the reverse of what
 
 ELEMENTAL PARTS. 157 
 
 is assumed. The only effect of this hypothesis 
 is to make us lose sight of the principle which 
 ought to direct us in the observation of such 
 curious structures, as well as of the conclusions 
 to which an unbiassed mind would come. The 
 matter to be explained is simply this: the 
 chain of bones in the ear, which is so curiously 
 adapted in the mammalia to convey the vibra- 
 tions of the membrane of the tympanum to the 
 nerve of hearing, is not found in the organ of 
 hearing in birds ; but there is substituted a me- 
 chanism entirely different. They choose to say 
 that the incus, one of the four bones of the chain, 
 is wanting in the bird. Where shall we find it? 
 they ask. Here it is in the apparatus of the 
 jaw or mandible ; in that bone which is called 
 05 quadratum. I believe that the slight and 
 accidental resemblance which this bone (B.) (see 
 figure p. 159) in the bird has to the incus, is the 
 real origin of this fancy. Let us follow a juster 
 mode of reasoning, and see how this hypothesis 
 obscures the beauty of the subject. The first 
 step of the investigation ought to be to inquire 
 into the fact, if there be any imperfection in the 
 hearing of birds. That is easily answered the 
 hearing of birds is most acute ; the slightest 
 noise alarms ; and the nightingale or other bird 
 of song, in a summer evening, will answer to the 
 note of his rival when he is out of our hearing. 
 We have next to observe the imperfection in the
 
 158 THEORY OF 
 
 organ the want of an external ear; which, were 
 it present, would be at variance with all that 
 we have most to admire in the shape of the 
 bird and the direction of the feathers, as con- 
 ducing to its rapid passage through the air. 
 With this obvious defect of the external ear, can 
 we admit that the internal ear is also imperfect, 
 notwithstanding the very remarkable acuteness 
 of hearing, which we know to result from this 
 internal structure, and from it alone ? Now we 
 do, in fact, find a different structure in the ear of 
 birds; but, yet nothing is wanting. The columella 
 is a shaft of bone of exquisite delicacy, which is 
 extended from the outward membrane of the ear 
 to the labyrinth or proper seat of the nerve of 
 hearing. It occupies the place and performs the 
 office of the chain of four bones which belortg to 
 the ear of mammalia. We have no authority, 
 however, for affirming that the incus is here 
 wanting more than any other bone of the chain. 
 
 From this mode of inquiry, we find that the 
 sense of hearing is enjoyed in an exquisite de- 
 gree in birds : that the organ of the sense is not 
 imperfect, but is adapted to a new construction, 
 and a varied apparatus suited to the condition 
 of the bird : and that there is no accidental dis- 
 location or substitution of something less perfect 
 than what we find in other classes of animals. 
 
 If we now look to the structure of the mandi- 
 ble of the bird, we shall find as curious, though
 
 ELEMENTAL PARTS. 159 
 
 a somewhat grosser example of mechanical rela- 
 tion. The bill of the bird, in some degree, per- 
 tains to our subject, as it is the organ of pre- 
 hension and of touch. It is withal a fly trap 
 hence, its motions must be rapid : and the velo- 
 city is increased by the most obvious means 
 imaginable, that is, by giving motion to both 
 mandibles, instead of to one. When a dog snaps, 
 he throws back his head, and thereby raises the 
 upper jaw at the same time that the lower jaw is 
 dropped ; but these are slow and clumsy motions, 
 pertaining to the muscles of the neck as well as 
 of the jaws, and the poor hound makes many 
 attempts, before he catches the fly that teazes 
 him. But a swallow or fly-catcher makes no 
 second effort, so admirably suited is the appara- 
 tus of prehension to the liveliness of the eye and 
 the instinct. The adaptation of the instrument 
 consists in this, that the muscles which open the 
 
 lower mandible, by the same effort, open the 
 upper one : A. is a process of the lower mandible, 
 projecting behind the centre of motion, and
 
 1(50 THEORY OF THE 
 
 the muscle which is attached to it, opens the 
 bill ; but at the same time, the lower mandible 
 presses upon the bone B., the os quadratum: 
 now, there is attached to this bone, projecting 
 forwards, with its anterior extremity fixed 
 against the upper mandible, a shaft or process 
 of bone c.; and this receives the pressure of the 
 os quadratum, when the muscle acts; so that 
 being thrust forwards, like a bolt, it opens the 
 upper mandible, which moves upon the skull at 
 D.* Here, then, is a piece of mechanism as dis- 
 tinct as the lock of a gun, which is for the pur- 
 pose, as we have said, of giving rapidity to the 
 motions of the bill. Is it nearer the truth to 
 consider this as a new apparatus, suiting the 
 necessities of the creature, or an accidental result 
 of the introduction of a bone, which in its proper 
 office has nothing to do with the jaw ? 
 
 But we have wandered somewhat from our 
 subject. We have before taken the bones of the 
 shoulder, or those of the extremity which are 
 nearest to the trunk; we may pursue the inquiry 
 by noticing those which are most remote from it. 
 In the bones corresponding with those of the 
 hand, we have seen that the same system was 
 variously modified so as to be adapted to every 
 possible change in office. But as it is insisted 
 that the number of parts continue the same, 
 
 * There is another process of the os quadratum, which, 
 directed mere internally, assists in raising the upper mandible.
 
 SURROUNDING INFLUENCE. 161 
 
 what can we say to the bones of the paddle in 
 the saurian and chelonian tribes ? These, as in 
 the ichthyosaurus for example, consist of sixty 
 or seventy polygonous bones; whilst in the 
 horse there are only fifteen bones ; arid in man, 
 twenty-seven. Yet, with all those bones in the 
 paddle, there is still the full complement in the 
 part that corresponds with the arm and fore 
 arm. If the system fail us in such an obvious 
 instance as this, with what confidence can we 
 prosecute the intricate bones of the spine and 
 head under its guidance ? * 
 
 Seeking assistance from the works of distin- 
 guished naturalists, we do not always find that 
 disposition of mind prevail, which we should be 
 apt to suppose a necessary result of their pecu- 
 liar studies. We do not discover that combina- 
 tion of genius with sound sense, which distin- 
 guished Cuvier, and the great men of science. 
 It is, above all, surprising with what perverse 
 ingenuity men seek to obscure the conception of 
 a Divine Author, an intelligent, designing, and 
 benevolent Being rather clinging to the greatest 
 absurdities, or interposing the cold and inani- 
 mate influence of the mere " elements," in a 
 manner to extinguish all feeling of dependance 
 in our minds, and all emotions of gratitude. 
 
 * See Additional Illustrations, On the position of the 
 Head, %c.
 
 H5-J THEORY OF THE 
 
 Some will maintain that all the varieties 
 which we see, are the result of a change of cir- 
 cumstances influencing the original animal ; or 
 that new organs have been produced by a desire 
 and consequent effort of the animal to stretch 
 and mould itself that, as the leaves of a plant 
 expand to light, or turn to the sun, or as the 
 roots shoot to the appropriate soil, so do the 
 exterior organs of animals grow and adapt them- 
 selves. We shall presently find that an opinion 
 has prevailed that the organization of animals 
 has determined their propensities ; but the phi- 
 losophers, of whom we are now speaking, ima- 
 gine the contrary, that under the influence of 
 new circumstances, organs have accommodated 
 themselves, and assumed their particular forms. 
 
 It must be here remarked that there are no 
 instances of the production of new organs by 
 the union of individuals belonging to different 
 species. Nor is there any foundation in obser- 
 vation for the opinion that a new species may 
 be formed by the union of individuals of dif- 
 ferent families. But it is contended, that, 
 although the species of animals have not changed 
 in the last 5000 years, we do not know what 
 might have been the effect of the revolution 
 before that time ; that is, previous to the pre- 
 sent condition of the world. On subjects of this 
 nature, however, we must argue from what we 
 know, and from what we see.
 
 SURROUNDING INFLUENCE. 163 
 
 We do perceive surprising changes in the 
 conformation of animals. Some of them are 
 very familiar to us ; but all show a foreknow- 
 ledge and a prospective plan, an alteration 
 gradually taking place in preparation for the 
 condition, never consequent upon it. It will be 
 sufficient for our purpose, if we take the highest 
 and the lowest examples. Man has two con- 
 ditions of existence in the body. Hardly two 
 creatures can be less alike than an infant and a 
 man. The whole foetal state is a preparation 
 for birth. My readers would not thank me, 
 were I to show how necessary all the proportions 
 and forms of the infant are to his being born 
 alive, and yet nothing is so easy to demon- 
 strate. Every one may see that from the 
 moment of birth there is a new impulse given 
 to the growth, so as finally to adapt the pro- 
 portions of the body to the state of perfect man- 
 hood. Few, however, are aware that the foetus 
 has a life adapted to its condition, and that if 
 the confinement of the womb were protracted 
 beyond the appointed time, it must die ! from 
 no defect of nourishment, but simply, because 
 the time is come for a change in its whole 
 economy ! 
 
 Now, during all the long period of gestation, 
 the organs are forming ; the lungs are perfected 
 before the admission of air new tubes are con- 
 structed before the flood-gates, which are to
 
 104 THEORY OF THE 
 
 admit the blood, are opened. But there are 
 finer, and more curious, provisions than these. 
 If we take any of the grand organs, as the 
 heart, or the brain, and examine it through all 
 its gradations of change in the embryo state, we 
 shall recognise it simple, at first, and gradually 
 developing, and assuming the peculiarities which 
 finally distinguish it. So that it is affirmed, and 
 not without the support of a most curious series 
 of observations, that the human brain, in its 
 earlier stage, resembles that of a fish : as it is 
 developed, it resembles more the cerebral mass 
 of the reptile ; in its increase, it is like that of 
 a bird, and slowly, and only after birth, does it 
 assume the proper form and consistence of the 
 human encephalon. But in all these changes 
 to which man is subject, we nowhere see the 
 influence of the elements, or any other cause 
 than that it has been so predestined. And if, 
 passing over the thousand instances which might 
 be gathered from the intermediate parts of the 
 chain of animal existence, we take the lowest 
 link, and look to the metamorphosis of insects, 
 the conclusion will be the same. 
 
 For example, if we examine the larva of a 
 winged insect, we shall see the provisions for its 
 motion over the ground, in that condition, all 
 admirably supplied in the arrangement of its 
 muscles, and the distribution of its nervous 
 system. But if, anticipating its metamorphosis,
 
 SURROUNDING INFLUENCE. 165 
 
 we dissect the same larva immediately before 
 the change, we shall find a new apparatus in 
 progress towards perfection ; the muscles of its 
 many feet are seen decaying ; the nerves to 
 each muscle are wasting ; a new arrangement 
 of muscles, with new points of attachment, di- 
 rected to the wings instead of the feet, is now 
 visible ; and a new distribution of nerves is dis- 
 tinctly to be traced, accommodated to the parts 
 which are now to be put in motion. Here is no 
 budding and stretching forth under the influence 
 of the surrounding elements ; but a change 
 operated on all the economy, and prospective, 
 that is, in reference to a condition which the 
 creature has not yet attained. 
 
 These facts countenance the conclusion drawn 
 from the comparative anatomy of the hand and 
 arm that with each new instrument, visible ex- 
 ternally, there are a thousand internal relations 
 established : a mechanical contrivance in the 
 bones and joints, which alters every part of 
 the skeleton : an arrangement of muscles, in. 
 just correspondence : a new and appropriate 
 texture of nervous filaments, which is laid inter- 
 mediate between the instrument and the very 
 centre of life and motion ; and, finally, we shall 
 discover as we proceed, that new sources of ac- 
 tivity must be created in relation to the new 
 organ, otherwise the part will hang a useless 
 appendage. 
 
 B. x
 
 166 THESE THEORIES INCORRECT. 
 
 It must now be apparent that nothing less 
 than the Power, which originally created, is 
 equal to the effecting of those changes on ani- 
 mals, which are to adapt them to their con- 
 ditions : that their organization is predetermined, 
 and not consequent on the condition of the 
 earth or the surrounding elements. Neither can 
 a property in the animal itself, account for the 
 changes which take place in the individual, any 
 more than for the varieties which take place 
 in the species. Every thing declares the species 
 to have its origin in a distinct creation, not in 
 a gradual variation from some original type; 
 and any other hypothesis than that of a new 
 creation of animals suited to the successive 
 changes in the inorganic matter of the globe 
 the condition of the water, atmosphere, and tem- 
 perature brings with it only an accumulation 
 of difficulties. 
 
 We ought here to bring into the argument 
 a series of changes of structure, of a different 
 nature altogether : we mean the revolution that 
 is taking place, without a pause during the 
 whole life, in the frame of every individual 
 animal. No description of the mechanical parts 
 of the living body, or even of the forms, the 
 instruments, or the organs of sense which have 
 relation to external objects, can convey an idea 
 of the power that is continually in operation,
 
 THE ANIMAL SYSTEM, ITS REVOLUTIONS. 167 
 
 unless we contemplate the influence of life 
 itself, in collecting, arranging, and incessantly 
 changing the material of the frame. Astounded 
 by the magnitude of natural objects, bewildered 
 by seeing neither beginning nor end, permitted 
 only to witness those instances of decay which 
 would almost persuade us that all objects in 
 nature were given up to a power of destruction, 
 it must be useful to have the proofs in the 
 microcosm of the living body, that a system may 
 be continued, whilst every portion of the sub- 
 stance suffers change. 
 
 Life draws the materials of the body apart 
 from the influence of those affinities which hold 
 the inorganic world together, and substitutes 
 other laws. The wonders of the microscope are 
 not greater than should be excited by looking 
 to the early rudiments of some animal, it may 
 be the largest that inhabits the earth. In a 
 small portion of matter that seems homogeneous, 
 transparent, soft, and like a jelly, there is only 
 a pulsating point visible. What might be seen 
 by employing the newly discovered properties 
 of light, it is impossible to say ; as polarized 
 light exhibits in mineral bodies a structure 
 not visible before, so we could imagine that 
 some power bestowed upon our eye might dis- 
 cover a distinction of parts in what seems a 
 drop of jelly. But the greater wonder is in 
 proof before us, that this mass has a principle
 
 168 THE ANIMAL SYSTEM, ITS REVOLUTIONS. 
 
 of life that it is not only ordered what this 
 influence will perform, in attracting matter, and 
 building up the complex structure of an animal 
 body, but that the period of existence of that 
 body is from its beginning defined. This life 
 may be limited to a day, and truly ephemeral, 
 or be protracted to a hundred years : and the 
 period is adjusted, as perfectly as the mechanism 
 and structure itself, to the condition of existence, 
 the enjoyment of the individual, and the con- 
 tinuance of the species. 
 
 Nothing is more remarkable than the slight 
 hold by which this life is possessed by some of 
 these organic structures, and the tenacity of life 
 in others. Slight changes of temperature or 
 moisture will annihilate some, whilst others will 
 be dried up into dust, or ribbed in ice, and after 
 years admit of resuscitation. 
 
 If instead of contemplating the variety of 
 animals as they are adapted to their place, we 
 think of ourselves there is no living creature 
 in which it is so distinctly designed that the 
 stages of life shall be marked so that we may 
 have continually before us the tenure by which 
 we hold that life. But to our argument ; 
 during all the progressive changes of life, the 
 material is ever new ; the poet's picture of the 
 last stage of man's life is not a true one. If man 
 totters under the burthen of years, the simile of 
 a ruin is inapplicable ; the material of his frame
 
 THE ANIMAL SYSTEM, ITS REVOLUTIONS. 169 
 
 is not different, and not older than that of a 
 child it is ever decaying, ever renewing whilst 
 the office of digestion and assimilation goes on 
 at all. The difference of activity in this change 
 of the material of the body, compared with that 
 of the child, may be as a week to a day ; but 
 here is not the cause of the gray hair, faded 
 cheek, and feeble step. This is the stamp which 
 the Creator has intended to be deciphered and 
 interpreted. 
 
 Who, contemplating the many beautiful fabrics 
 built up within an animal body, and seeing the 
 proofs that they are not permanent, but, on the 
 contrary, ever changing and ever forming anew 
 moreover, learning that these textures are 
 formed by an energy, or life, which continues 
 uniform in its operation, whilst all the mate- 
 rials that it works upon are changing can hesi- 
 tate to believe that in the changes of the inor- 
 ganic matter around us there is a presiding 
 Power. The difficulty of comprehension here 
 must be attributed to the partial view which we 
 have of these changes, from their extending 
 into periods so far beyond our measure of time : 
 but we cannot, at least, doubt that such a power 
 may be in operation, and we must acknowledge 
 that a balance is preserved, and that order and 
 harmony prevail.
 
 170 
 
 CHAPTER VII. 
 
 OF SENSIBILITY AND TOUCH. 
 
 WE find every organ of sense, with the excep- 
 tion of that of touch, more perfect in brutes 
 than in man. In the eagle and the hawk, in the 
 gazelle and in the feline tribe, the perfection of 
 the eye is admirable ; in the dog, wolf, hyaena, 
 as well as in birds of prey, the sense of smelling 
 is inconceivably acute ; and if we should have 
 some hesitation in assigning a more exquisite 
 sense of taste to brutes, we cannot doubt the 
 superiority of that of hearing in the inferior 
 animals. But in the sense of touch, seated in 
 the hand, man claims the superiority ; and it is 
 of consequence to our conclusion that we should 
 observe why it is so. 
 
 It has been said that, accompanying the 
 exercise of touch, there is a desire of obtaining 
 knowledge ; in other words, a determination of 
 the will towards the organ of the sense. Bichat 
 says, it is active whilst the other senses are 
 passive. This opinion implies that there is 
 something to be understood something deeper 
 than what is here expressed. We shall arrive at 
 the truth by considering that in the use of the
 
 OF SENSIBILITY AND TOUCH. 171 
 
 hand there is a double sense exercised; we 
 must not only feel the contact of the object, but 
 we must be sensible to the muscular effort which 
 is made to reach it, or to grasp it in the fingers. 
 It is in the exercise of this latter power that 
 there is really an effort made ; there is no more 
 direction of the will towards the nerve of touch, 
 than towards any other sensible nerve. But, 
 before entering on the consideration of the sen- 
 sibility and action which belong to the fingers, 
 we must attend to the common sensibility of the 
 surface. 
 
 Besides that the common sensibility belongs 
 to the hand, and that some inquiry into it is 
 necessary to the completion of our subject, I 
 pursue it the more willingly, because there is no 
 other which affords more surprising proofs of 
 design and of benevolence in the Author of our 
 being. However obvious the proofs may be 
 which are drawn from the mechanism of the 
 body, they are not to be compared, in that res- 
 pect, to those which are derived from the living 
 endowments of the frame. 
 
 I have used the term common sensibility in 
 conformity with the language of authors and 
 with customary parlance ; but the expressions, 
 the " common nerves," and the " common sensi- 
 bility," in a philosophical inquiry, are inadmis- 
 sible. Indeed, these terms have been the cause 
 of much of the obscurity which has hung over
 
 172 OF SENSIBILITY AND TOUCH. 
 
 the subject of the nervous system, and of our 
 blindness to the benevolent adaptation of the 
 endowments of that system to the condition of 
 animal existence. Thus, it has been supposed 
 that some nerves are more coarsely provided for 
 sensation, and that others are of a finer quality, 
 adapted to more delicate impressions. It is as- 
 sumed that the nerve of the eye is finer than 
 the nerve of the finger without considering 
 that the retina is insensible to that quality of 
 matter of which we readily acquire the know- 
 ledge through touch. Nerves are, indeed, ap- 
 propriated to peculiar senses, and to the bestow- 
 ing of distinct functions, but delicacy of texture 
 has nothing to do with this. The nerve of touch 
 in the skin is insensible to light or to sound, not 
 because it has a coarser or more common tex- 
 ture : the beauty and perfection of the system 
 is, that each nerve is made susceptible to its 
 peculiar impression only. The nerve of the 
 skin is alone capable of giving the sense of 
 contact, as the nerve of vision is confined to its 
 own office. If this appropriation resulted merely 
 from a more delicate texture : if the retina were 
 sensible to the matter of light only from pos- 
 sessing a finer sensibility than the nerve of 
 touch, it would be a source of torment ; whereas 
 it is most beneficently provided that it shall not 
 be sensible to pain, nor be capable of conveying 
 any impressions to the mind, but those which
 
 OF SENSIBILITY AND TOUCH. ] 73 
 
 operate according to its proper function, pro- 
 ducing light and colour. 
 
 The pain which we experience in the eye, 
 and the irritation from dust, are owing to a dis- 
 tinct nerve from that of vision, and are conse- 
 quent on the susceptibility of the surface to a 
 different kind of impression ; of which more 
 presently. We should keep in mind the in- 
 teresting fact, that when surgeons perform the 
 operation of couching, the point of the needle, 
 in passing through the outer coat of the eye, 
 gives a sensation of pricking, which is an exer- 
 cise of the nerve of touch ; but when the point 
 passes through the retina, which is the expanded 
 nerve of vision, and forms the internal coat of 
 the eye, the sensation that is produced is as of a 
 spark of fire. The nerve of vision is as insen- 
 sible to touch as the nerve of touch is to light.* 
 
 The extreme sensibility of the skin to the 
 slightest injury conveys to every one the notion 
 ' that the pain must be the more severe the 
 deeper the wound. This is not the fact, nor 
 would it accord with the beneficent design 
 
 * The views of the nervous system, which are shortly given 
 in the text, guided me in my original experiments made twenty - 
 two years ago. They have been attributed to foreign physio- 
 logists. The ignorance of what has been done in England, 
 may be, for strangers, an excuse for maintaining these opinions 
 as their own ; but the authors at home, who should have known 
 what has been taught in this country, are inexcusable when they 
 countenance these assumptions.
 
 174 SENSIBILITY OF THE SURFACE 
 
 which shines out every where. The sensibility 
 of the skin serves not only to give the sense 
 of touch, but it is a guard upon the deeper 
 parts; and as they cannot be reached except 
 through the skin, and we must suffer pain, 
 therefore, before they are injured, it would be 
 superfluous to bestow sensibility upon these 
 deeper parts. If the internal parts which act 
 in the motions of the body had possessed a 
 similar degree and kind of sensibility with the 
 skin, so far from serving any useful purpose, 
 this sensibility would have been a source of 
 inconvenience and continual pain in the com- 
 mon exercise of the frame. 
 
 Surgeons have better opportunities of ad- 
 vancing physiology than physicians, as they 
 become practically acquainted with the pheno- 
 mena on which the science is founded. The 
 surgeon who has to perform an operation by 
 incision, when he has cut through the skin, 
 informs his patient that the greatest pain is over. 
 If, in the advanced stage of the operation, he 
 has to extend the incision of the skin, it is very 
 properly considered as a great awkwardness; 
 and this not only because it proves that he has 
 miscalculated what was necessary to the correct 
 performance of his operation, but because the 
 patient, bearing courageously the deeper inci- 
 sions, cannot sustain the renewed cutting of the 
 skin, without giving token of severe pain.
 
 COMPARED WITH THE DEEPER PARTS. 175 
 
 The fact of the exquisite sensibility of the 
 surface, in comparison with the deeper parts, 
 being thus ascertained by daily experience, we 
 cannot mistake the intention : that the skin is 
 made a safeguard to the delicate textures which 
 are contained within, by forcing us to avoid 
 injuries: and it does afford us a more effectual 
 defence than if our bodies were covered with the 
 hide of the rhinoceros. 
 
 The fuller the consideration which we give 
 to this subject, the more convincing are the 
 proofs that the painful sensibility of the skin 
 is a benevolent provision, making us alive to 
 those injuries, which, but for this quality of 
 the nervous system, would bruise and destroy 
 the internal and vital parts. In pursuing the 
 inquiry, we learn with much interest that when 
 the bones, joints, and all the membranes and 
 ligaments which cover them, are exposed they 
 may be cut, pricked, or even burned, without 
 the patient or the animal, suffering the slightest 
 pain. These facts must appear to be conclusive ; 
 for who, witnessing these instances of insensi- 
 bility, would not conclude that the parts were 
 devoid of sensation. But when we take the true, 
 philosophical, and I may say the religious view 
 of the subject, and consider that pain is not 
 an evil, but given for benevolent purposes and 
 for some important object, we should be un 
 willing to terminate the investigation here.
 
 17(5 SENSIBILITY OF THE SURFACE 
 
 In the first place, we must perceive that if a 
 sensibility similar to that of the skin had been 
 given to these internal parts, it must have re- 
 mained unexercised. Had they been made sen- 
 sible to pricking and burning, they would have 
 possessed a quality which would never have 
 been useful, since no such injuries can reach 
 them ; or never without warning being received 
 through the sensibility of the skin. 
 
 But, further, if we find that sensibility to pain 
 is a benevolent provision, and is bestowed for 
 the purpose of warning us to avoid such violence 
 as would affect the functions or uses of the 
 parts, we may yet inquire whether any injury 
 can reach these internal parts without the sensi- 
 bility of the skin being excited. Now, of this 
 there can be no doubt, for they are subject to 
 sprain and rupture, and shocks, without the 
 skin being implicated in the accident. If we 
 have been correct in our inference, there should 
 be a provision to guide us in the safe exercise of 
 the limbs : and notwithstanding what has been 
 apparently demonstrated of the insensibility of 
 these internal parts, they must possess an ap- 
 propriate sensibility, or it would imply an 
 imperfection. 
 
 With these reflections, we recur to expe- 
 riment and we find that the parts which 
 are insensible to pricking, cutting, and burning,
 
 COMPARED WITH THE DEEPER PARTS. 177 
 
 are actually sensible to concussion, to stretching, 
 or laceration. 
 
 How consistent, then, and beautiful is the 
 distribution of this quality of life! The sen- 
 sibility to pain varies with the function of the 
 part. The skin is endowed with sensibility to 
 every possible injurious impression which may 
 be made upon it. But had this kind and degree 
 of sensibility been made universal, we should 
 have been racked with pain in the common 
 motions of the body : the mere weight of one 
 part on another, or the motion of the joint, 
 would have been attended with that degree of 
 suffering which we experience in using or walk- 
 ing upon an inflamed limb. 
 
 But on the other hand, had the deeper parts 
 possessed no sensibility, we should have had 
 no guide in our exertions. They have a sen- 
 sibility limited to the kind of injury which it 
 is possible may reach them, and which teaches 
 us what we can do with impunity. If we leap 
 from too great a height, or carry too great a 
 burthen, or attempt to interrupt a body whose 
 impetus is too great for us, we are warned of 
 the danger as effectually by this internal sen- 
 sibility, as we are of the approach of a sharp 
 point or a hot iron to the skin. 
 
 Returning to the consideration of the sensi- 
 bility of the skin, in order more fully to com-
 
 178 PAIN THE SAFEGUARD OF THE BODY. 
 
 prehend the benevolent effect of it, or in other 
 words, its necessity to our very existence, I 
 may be excused for stating the argument to the 
 reader as I have delivered it in my lectures to 
 the College of Surgeons. 
 
 " Without meaning to impute to you inatten- 
 " tion or restlessness, I may request you to ob- 
 " serve how every one occasionally changes his 
 " position and shifts the pressure of the weight 
 " of his body ; were you constrained to retain 
 " one position during the whole hour, you would 
 " rise stiff and lame. The sensibility of the 
 " skin is here guiding you to that, which if neg- 
 " lected, would be followed even by the death of 
 " the part. When a patient has been received 
 " into the hospital with paralysis of the lower 
 " part of the body, we must give especial di- 
 " rections to the nurse and attendants that the 
 " position of his limbs be changed at short 
 " intervals, that pillows be placed under his 
 " loins and hams, and that they be often shifted. 
 " If this be neglected, you know the conse- 
 " quence to be inflammation of the parts tfmt 
 " press upon the bed ; from which come local 
 " irritation, then fever and mortification and 
 " death. 
 
 " Thus you perceive that the natural sensi- 
 " bility of the skin, without disturbing your 
 " train of thought, induces you to shift the body 
 " so as to permit the free circulation of the
 
 SENSIBILITY TO HEAT. 179 
 
 " blood in the minute vessels: and that when 
 " this sensibility is wanting, the utmost atten- 
 " tion of friends and the watchfulness of the 
 " nurse are but a poor substitute for this pro- 
 " tection which nature is continually affording. 
 " If you suffer thus lying on a soft bed, when 
 " deprived of the sensibility of the skin, how 
 " could you encounter without it the rubs and 
 " impulses incident to an active life ? You must 
 " now acknowledge that the sensibility of the 
 " skin is as much a protection to the frame 
 " generally, as the sensibility of the eyelids is to 
 " the eyes, and gives you a motive for gratitude 
 " which probably you never thought of." 
 
 The sensibility of the hand to heat, is a dif- 
 ferent endowment from that of touch. This sen- 
 sibility to the varieties of temperature is seated 
 in the skin, and is, consequently, limited to the 
 exterior surface of the body. The internal parts 
 of the body being of a uniform temperature, it 
 would have been, in them, a quality altogether 
 superfluous. But as we are surrounded by a 
 temperature continually varying, and are subject 
 to destruction by its extremes, and as we must 
 suit our exertions or our contrivances so as to 
 sustain life against these vicissitudes, our pos- 
 session of this peculiar sensibility on the surface 
 affords another proof of there having been a 
 foreknowledge of our condition. We might, in- 
 deed, take our former example in evidence of
 
 180 SENSIBILITY TO HEAT. 
 
 what must befall through the want of this sen- 
 sibility the paralytic is brought to us severely 
 burned, or with his extremities mortified through 
 cold. A man having lost the sense of heat in 
 his right hand, but retaining the muscular 
 power, lifted the cover of a pan which had fallen 
 into the fire and deliberately replaced it, not 
 being conscious that it was burning hot; the 
 effect, however, was the death and destruction 
 of the skin of the palm and fingers. In this 
 man there was a continual sensation of coldness 
 in the affected arm, which actual cold applied 
 to the extremity did not aggravate, nor heat in 
 any degree assuage.* Sensibility to heat is a 
 safeguard in as much as it is capable of be- 
 coming a painful sensation, whilst it is a never- 
 failing excitement to activity and a continual 
 source of enjoyment. 
 
 And here we may remark an adaptation of 
 the living property very different from the phy- 
 sical influence. Heat is uniform in its effect on 
 matter ; but the sensation varies as it is given 
 to or abstracted from the living body. Cold 
 and heat are distinct sensations ; and this is 
 so far important that without such contrast we 
 should not continue to enjoy the sense. For 
 in the nervous system it holds universally that 
 
 * There are certain morbid conditions of sensation when cold 
 bodies feel intensely hot. Dr. Abcrcrombie' s Inquiry into the 
 intellectual jxurcrs.
 
 SENSIBILITY OF THE EYE. 181 
 
 variety or contrast is necessary to sensation, the 
 finest organ of sense losing its property by the 
 continuance of the same- impression. It is by 
 a comparison of cold and heat that we enjoy 
 either condition. 
 
 To contrast still more strongly the sensibility 
 of the surface with the property of internal parts, 
 to show how very different sensibility is, in 
 reality, from what is suggested by first expe- 
 rience, and how admirably it is varied and ac- 
 commodated to the functions, we shall add one 
 other fact. The brain is insensible that part of 
 the brain, which if disturbed or diseased, takes 
 away consciousness, is as insensible as the 
 leather of our shoe ! That the brain may be 
 touched, or a portion of it cut off, without inter- 
 rupting the patient in the sentence that he is 
 uttering, is a surprising circumstance! From 
 this fact Physiologists formerly inferred that the 
 surgeon had not reached the more important 
 organ of the brain. But that opinion arose from 
 the notion prevailing that a nerve must neces- 
 sarily be sensible. Whereas, when we consider 
 that the different parts of the nervous system 
 have totally distinct endowments, and that there 
 are nerves, as I have elsewhere shown, insen- 
 sible to touch and incapable of giving pain, 
 though exquisitely alive to their proper office, 
 we have no just reason to conclude that the 
 brain should be sensible, or exhibit the property
 
 182 SENSIBILITY OF THE EYE. 
 
 of a nerve of the skin. Reason on it as we 
 may, the fact is so ; the brain, through which 
 every impression must be conveyed before it is 
 perceived, is itself insensible. This informs us 
 that sensibility is not a necessary attendant on 
 the delicate texture of a living part, but that it 
 must have an appropriate organ, and that it is 
 an especial provision.* 
 
 To satisfy my reader on this interesting sub- 
 ject, I shall take the contrast of two organs, one 
 external and exposed, and the other internal and 
 carefully excluded from injury. 
 
 The eye, consisting of its proper nerve of 
 vision and its transparent humours and coats, is 
 an organ of exquisite delicacy not only is it 
 exposed to all the injuries to which the general 
 surface of the body is liable, but to be inflamed 
 and rendered opaque by particles getting into it 
 which are so light that they float in the atmos- 
 phere, and to the contact of which the common 
 skin is quite insensible. The mechanical, and 
 more obvious contrivance for the protection of 
 this organ, is a ready motion of the eyelids and 
 the shedding of tears; which coming, as it were, 
 from a little fountain, play over the surface of 
 the eye, and wash away whatever is offensive. 
 But to the action of this little hydraulic and 
 mechanical apparatus there is required an ex- 
 
 See the Sensibility of the Retina, " Additional Illustrations."
 
 SENSIBILITY OF THE EYE. 183 
 
 quisite sensibility to direct it not that kind of 
 sensibility which enables the eye to receive the 
 impressions of light but a property more re- 
 sembling the tenderness of the skin, yet happily 
 adapted, by its fineness, to the condition of the 
 organ. 
 
 A nerve, possessed of a quality totally differ- 
 ent from that of the optic nerve, extends over all 
 the exterior surfaces of the eye, and gives to 
 those surfaces their delicate sensibility. Now it 
 sometimes happens that this nerve is injured and 
 its function lost ; the consequences of which are 
 very curious, smoke and offensive particles, 
 which are afloat in the atmosphere, rest upon 
 the eye : flies and dust lodge under the eyelids, 
 without producing sensation, and without ex- 
 citing either the hydraulic or the mechanical 
 apparatus to act for the purpose of expelling 
 them. But although they do not give pain, 
 they nevertheless stimulate the surfaces so as to 
 produce inflammation, and that causes opacity 
 in the fine transparent membranes of the eye ; 
 and the organ is lost, although the proper 
 nerve of vision remains entire. I have seen 
 many instances of the eye being thus destroyed 
 for want of sensibility to touch,* and it has been 
 curious to remark, on these occasions, that when 
 
 * They are stated at length in my papers in the Philosophical 
 Transactions, and in the Appendix of my work on the Nervous 
 System. - - "
 
 184 SENSIBILITY OF THE EYE. 
 
 the hand was waved or a feather brought near 
 the eye, the person winked ; yet he did not shut 
 his eye on rubbing the finger across the eyeball, 
 or when blood was removed by the lancet from 
 the inflamed vessels. In those cases, when 
 vision gave notice of danger to the organ, the 
 patient winked to avoid it, but when the point 
 touched the eye or eyelids, the sense of touch 
 gave no alarm, and was followed by no action 
 for the protection of the organ. 
 
 I shall present another instance of the pecu- 
 liar nature of the sensibility which protects the 
 eye. The Oculist has observed that by the 
 touch of a thing as light as a feather, the muscles 
 of the eye will be thrown into uncontrollable 
 actions and spasms : but if the point of the 
 finger be pressed somewhat rudely between the 
 eyelids, and directly on the eye itself, he can by 
 such means hold the eye steady for his intended 
 operation, producing hardly any sensation, cer- 
 tainly no pain ! 
 
 This is one of the little secrets of the art ; 
 the Oculist turns out the eyelids, and lingers 
 the eye, in a manner which appears, at once, 
 rude and masterly : and still the wonder grows 
 that he can do such things with so much dex- 
 terity as to inflict no pain, when by daily experi- 
 ence we know that even a grain of sand in the 
 eye will torture us. The explanation is this : the 
 eye and eyelids are possessed of a sensibility
 
 SENSIBILITY OF THE HEART. 185 
 
 which is adjusted to excite the action of its pro- 
 tecting parts against such small particles as 
 might lodge and inflame its fine membranes. 
 But the apparatus is not capable of protecting 
 the surface of the eye against the intrusion of a 
 stick or a stone ; from such injuries it could not 
 be defended by a delicate sensibility and invo- 
 luntary action, but only by the effort of the 
 will. ' 
 
 In these details we have new proofs of the 
 minute relation which is established between 
 the species of sensibility in an organ and the 
 end to be attained through it. It will not be de- 
 nied that if it were not for the pain to which the 
 eye is exposed, we should quickly lose the en- 
 joyment of the sense of vision altogether. But 
 we were about to institute a comparison of the 
 eye with the heart. 
 
 The observation of the admirable Harvey, the 
 discoverer of the circulation of the blood, is to 
 this effect. A noble youth of the family of 
 Montgomery, from a fall and consequent abscess 
 on the side of the chest, had the interior mar- 
 vellously exposed, so that after his cure, on his 
 return from his travels, the heart and lungs 
 were still visible and could be handled; which 
 when it was communicated to Charles I., he ex- 
 pressed a desire that Harvey should be per- 
 mitted to see the youth and examine his heart, 
 " When," says Harvey, " I had paid my re-
 
 186 SENSIBILITY OF THE HEART. 
 
 " spects to this young nobleman, and conveyed 
 ** to him the king's request, he made no con- 
 " cealment, but exposed the left side of his 
 " breast, when I saw a cavity into which I could 
 " introduce my fingers and thumb ; astonished 
 " with the novelty, again and again I explored 
 " the Wound, and first marvelling at the extra- 
 *' ordinary nature of the cure, I set about the 
 " examination of the heart. Taking it in one 
 " hand, and placing the finger of the other on 
 " the pulse of the wrist, I satisfied myself that it 
 " was indeed the heart which I grasped, I then 
 " brought him to the king, that he might behold 
 ' and touch so extraordinary a thing, and that 
 " he might perceive, as I did, that unless when 
 *' we touched the outer skin, or when he saw our 
 " fingers in the cavity, this young nobleman 
 " knew not that we touched the heart !" Other 
 observations confirm this great authority, and 
 the heart is declared insensible. And yet the 
 opinions of mankind must not be lightly con- 
 demned. Not only does every emotion of the 
 mind affect the heart, but every change in the 
 condition of the body is attended with a corres- 
 ponding change in the heart : motion during 
 health the influence of disease every passing 
 thought will influence it. Here is the distinction 
 manifested- The sensibility of the surface of 
 the eye is for a purpose, and so is the sensibility 
 of the heart. Whilst that of the eye guards it
 
 SENSIBILITIES OF EXTERNAL. PARTS, ETC. 187 
 
 against injury from without, the heart, insen- 
 sible to touch, is yet alive to every variation in 
 the circulation, subject to change from every 
 alteration of posture or of exertion, and is in 
 sympathy of the strictest kind with the consti- 
 tutional powers. 
 
 When we consider these facts, we can no 
 longer doubt that the sensibilities of the living 
 frame are appropriate endowments; not quali- 
 ties necessarily arising from life; still less the 
 consequences of delicacy of texture. Nor can 
 we, I should hope, longer doubt that they are 
 suited to the condition, and especially to the 
 degree of exposure of each part, and for its pro- 
 tection. We perceive that the sensibilities vary 
 in an extraordinary manner as they are given to 
 external or to internal parts, as they belong to 
 one apparatus of action or to another, and they 
 are ever adapted to excite some salutary or 
 necessary action. We perceive no instance of 
 pain being bestowed as a source of suffering or 
 punishment purely, or without finding it over- 
 balanced by great and essential advantages - 
 without, in short, being forced to admit that no 
 happier contrivance could be found for the pro- 
 tection of the part. It is provided that the 
 more an organ is exposed, and in proportion to 
 its delicacy of organization the more exqui- 
 sitely contrived is the apparatus for its protec- 
 tion, and the more peremptory the call for the
 
 IBB PLEASURABLE SENSATIONS COULU NOT 
 
 activity of that mechanism. The motive to 
 action admits of no thought and no hesitation, 
 and the action is more instantaneous than the 
 quickest suggestion or impulse of the will. 
 
 We are speaking of the natural functions of 
 the body. It requires a deeper consideration, 
 and is indeed foreign to my subject to speak of 
 the pains which result from disease, or to recon- 
 cile those who suffer in an extraordinary degree 
 to the dispensations of Providence. But as a 
 witness I may speak. It is my daily duty to 
 visit certain wards of the hospital, where there 
 is no patient admitted but with that complaint 
 which most fills the imagination with the idea of 
 insufferable pain and certain death. Yet these 
 wards are not the least remarkable for the com- 
 posure and cheerfulness of then* inmates. The 
 individual who suffers has a mysterious counter- 
 balance to that condition, which to us who look 
 upon her, appears to be attended with no alle- 
 viating circumstance. 
 
 It affords an instance of the boldness with 
 which philosophers have questioned the ways 
 of Providence, that they have asked why were 
 not all our actions performed at the suggestion 
 of pleasure ? why should we be subject to pain 
 at all? In answer to this I should say, in the 
 first place, that consistently with our condition, 
 our sensations and pleasures, there must be
 
 HAVE BEEN THE MOTIVES TO ACTION. 189 
 
 variety in the impressions ; such contrast and 
 variety are common to every organ of sense ; 
 and the continuance of an impression on any 
 one organ, occasions it to fade. If the eye 
 continue to look steadfastly upon one object, the 
 image is soon lost if we continue to look on 
 one colour, we become insensible to that colour, 
 and opposite colours to each other are necessary 
 for a perfect impression.* So have we seen that 
 in the sensibilities of the skin variations are 
 necessary to continued sensation. 
 
 It is difficult to say what these philosophers 
 would define as pleasure : but whatever exercise 
 of the senses it should be, unless we are to sup- 
 pose an entire change of our nature, its opposite 
 is also implied. Nay, further, in this fanciful 
 condition of existence, did anything of our pre- 
 sent nature prevail, emotions purely of pleasure 
 would lead to indolence, relaxation, and indif- 
 ference. To what end should there be an appa- 
 ratus to protect the eye, since pleasure could 
 never move us to its exercise ? Could the wind- 
 pipe and the interior of the lungs be protected 
 by a pleasurable sensation attended with the 
 slow determination of the will instead of the 
 rapid and powerful influence which the ex- 
 quisite sensibility of the throat has upon the 
 
 * See Additional Illustrations.
 
 190 PAIN NECESSARY TO EXISTENCE. 
 
 act of respiration, or those forcible yet regulated 
 exertions, which nothing but the instinctive ap- 
 prehension of death could excite ? 
 
 To suppose that we could be moved by the 
 solicitations of pleasure and have no experience 
 of pain, would be to place us where injuries 
 would meet us at every step and in every motion, 
 and whether felt or not, would be destructive to 
 life. To suppose that we are to move and act 
 without experience of resistance and of pain, 
 is to suppose not only that man's nature is 
 changed, but the whole of exterior nature also 
 there must be nothing to bruise the body or 
 hurt the eye, nothing noxious to be drawn in 
 with the breath : in short, it is to imagine alto- 
 gether another state of existence, and the phi- 
 losopher would be mortified were we to put this 
 interpretation on his meaning. Pain is the 
 necessary contrast to pleasure : it ushers us into 
 existence or consciousness : it alone is capable 
 of exciting the organs into activity: it is the 
 companion and the guardian of human life.
 
 CHAPTER VIII. 
 
 OF THE SENSES GENERALLY, INTRODUCTORY TO 
 THE SENSE OF TOUCH. 
 
 ALTHOUGH we are most familiar with the sen- 
 sibility of the skin, and believe that we per- 
 fectly understand the nature of the impressions 
 upon it and the mode of their conveyance to the 
 sensorium, yet there is a difficulty in compre- 
 hending the operations of all the organs of the 
 senses a difficulty not removed by the apparent 
 simplicity of that of touch. 
 
 There was a time when the enquirer was satis- 
 fied by finding that in the ear there was a little 
 drum and a bone to play upon it, with an ac- 
 companying nerve. This was deemed a suffi- 
 cient explanation of the organ of hearing. It 
 was thought equally satisfactory if, in experi- 
 menting upon the eye, the image of the object 
 were seen painted at the bottom on the surface 
 of the nerve. But although the impression be 
 thus traced to the extremity of the nerve, still we 
 comprehend nothing of the nature of that im- 
 pression, or of the manner in which it is trans-
 
 192 NATURE OF THE IMPRESSION. 
 
 mitted to the sensorium. To the most minute 
 examination, the nerves, in all their course, and 
 where they are expanded into the external organs 
 of sense, seem the same in substance and in 
 structure. The disturbance of the extremity of 
 the nerve, the vibrations upon it, or the images 
 painted upon its surface, cannot be transmitted 
 to the brain according to any physical laws that 
 we are acquainted with. The impression on the 
 nerve can have no resemblance to the ideas 
 suggested in the mind. All that we can say is, 
 that the agitations of the nerves of the outward 
 senses are the signals, which the Author of 
 nature has made the means of correspondence 
 with the realities. There is no more resem- 
 blance between the impressions on the senses 
 and the ideas excited by them, than there is 
 between the sound and the conception raised 
 in the mind of that man who, looking out on 
 a dark and stormy sea, hears the report of 
 cannon, which conveys to him the idea of 
 despair and shipwreck or between the im- 
 pression of light on the eye, and the idea of 
 him, who, having been long in terror of national 
 convulsion, sees afar off a column of flame, 
 which is the signal of actual revolt. 
 
 By such illustrations, however, we rather 
 show the mind's independence of the organ of 
 sense, and how a tumult of ideas will be excited 
 by an impression on the retina, which, notwith-
 
 ORIGIN OF IDEAS. 193 
 
 standing, may be no more intense than that 
 produced by a burning taper. They are in- 
 stances of excited imagination. But even the 
 determined relations which are established, in a 
 common act of perception, between the sensa- 
 tion and the idea in the mind, have no more 
 actual resemblance. How the consent, which 
 is so precise and constant, is established, can 
 neither be explained by anatomy nor by physio- 
 logy nor by any mode of physical inquiry 
 whatever. 
 
 From this law of our nature, that certain ideas 
 originate in the mind in consequence of the 
 operation of corresponding nerves, it follows 
 that one organ of sense can never become the 
 substitute for another, so as to excite in the 
 mind the same idea. 
 
 When an individual is deprived of the organs 
 of sight, no power of attention, or continued 
 effort of the will, or exercise of the other senses, 
 can make him enjoy the class of sensations 
 which is lost. The sense of touch may be in- 
 creased in an exquisite degree ; but were it true, 
 as has been asserted, that individuals can dis- 
 cover colours by the touch, it could only be by 
 feeling a change upon the surface of the stuff and 
 not by any perception of the colour. It has 
 been my painful duty to attend on persons who 
 have pretended blindness, and that they could 
 see with their fingers. But I have ever found
 
 194 ORIGIN OF IDEAS. 
 
 that by a deviation from the truth in the first in- 
 stance, they have been entangled in a tissue of 
 deceit; and have at last been forced into ad- 
 missions which demonstrated their folly and 
 weak inventions. I have had pity for such 
 patients when they have been the subjects of 
 nervous disorders which have produced extraor- 
 dinary sensibility in their organs such as a 
 power of hearing much beyond our common ex- 
 perience. This acuteness of sensibility having 
 attracted high interest and admiration has gra- 
 dually led them to pretend to powers greater than 
 they actually possessed. In such cases it is diffi- 
 cult to distinguish the symptoms of disease, from 
 the pretended gifts which are boasted of. 
 
 Experiment proves, what is suggested by 
 Anatomy, that not only the organs of the senses 
 are appropriated to particular classes of sensa- 
 tions, but that the nerves, intermediate between 
 the brain and the outward organs, are respec- 
 tively capable of receiving no other sensations 
 but such as are adapted to their particular organs. 
 Every impression on the nerve of the eye, or of 
 the ear, or on the nerve of smelling, or of taste, 
 excites only perceptions of vision, of hearing, 
 of smelling, or of tasting ; not solely because the 
 extremities of these nerves, individually, are 
 suited to external impressions, but because the 
 nerves, through their whole course and wher- 
 ever they are irritated, are capable of exciting
 
 MORBID SENSATIONS. 195 
 
 in the mind the idea to which they are appro- 
 priate, and no other. A blow, an impulse quite 
 unlike that for which the organs of the senses 
 are provided, will excite them all in their several 
 ways ; the eyes will flash fire, while there is 
 noise in the ears. An officer received a musket- 
 ball which went through the bones of his face 
 in describing his sensations, he said that he felt 
 as if there had been a flash of lightning, accom- 
 panied with a sound like the shutting of the door 
 of St. Paul's. 
 
 On this circumstance, that every nerve is 
 appropriated to its function, depend the false 
 sensations which accompany the morbid irrita- 
 tion of the nerves from internal causes, when 
 there is in reality nothing presented externally; 
 such as flashes of light, ringing of the ears, and 
 bitter taste or offensive smells. These sensa- 
 tions are caused, through the excitement of the 
 respective nerves of sense, by derangement of 
 some internal organ, and most frequently of the 
 stomach. 
 
 But my chief object is to show that the most 
 perfect proof of power and of design, is to be 
 found in this, that the perceptions or ideas 
 arising in the mind, are in correspondence with 
 the qualities of external matter ; and that, 
 although the manner in which the object pre- 
 sented to the outward sense and the idea of it 
 are connected, must ever be beyond our com-
 
 196 DOCTRINE OF UNDULATIONS. 
 
 prehension, they are, notwithstanding, indis- 
 solubly united ; and when the object is so 
 presented to us by the senses, it is attended with 
 the conviction of its real existence a convic- 
 tion, independent of reason and to be regarded 
 as a first law of our nature. 
 
 The doctrine of vibrations as applicable to 
 vision, has had powerful advocates in our day. 
 But it is quite at variance with anatomy, and 
 assumes more than is usually granted to hypo- 
 theses. It requires that we shall imagine the 
 existence of an ether; and that this fluid shall 
 have laws unlike any other of which we have 
 experience. It supposes a nervous fluid and 
 tubes or fibres in the nerve, to receive and 
 convey these vibrations. It supposes every- 
 where motion as the sole means of propagating 
 sensation. 
 
 These opinions have been formed on the mis- 
 conception that if a certain kind or degree of 
 vibration be communicated to any nerve, this 
 particular motion must be propagated to the sen- 
 sorium, and a corresponding idea excited in the 
 mind. For example, it is conceived that if the 
 nerve of hearing were placed in the bottom of 
 the eye, it would be impressed with the vibration 
 proper to light, and that this being conveyed 
 to the brain, the sensation of light or colours 
 would result. All which is contrary to fact. 
 
 Nor can I be satisfied with the statement that
 
 DOCTRINE OF UNDULATIONS. 197 
 
 light and colours result from vibrations which 
 vary " from four hundred and fifty-eight mil- 
 " lions of millions, to seven hundred and twenty - 
 " seven millions of millions in a second," when 
 I find that a fine needle pricking the retina will 
 produce brilliant light, and that the pressure 
 of the finger on the ball of the eye will give rise 
 to all the colours of the rainbow ! 
 
 There is a condition of the percipient or 
 sentient principle, of the brain and nerves, as 
 well as of the organ of sense, conforming to 
 the impression to be made ; a condition which 
 corresponds with the qualities of matter. The 
 organs of sense may be compared to so many 
 instruments, which the philosopher applies to 
 distinguish the several qualities of the body 
 which he investigates. The different properties 
 of that body are not communicable through any 
 one instrument ; and so in the use of the senses, 
 each organ is provided for receiving a particular 
 influence, and no other. 
 
 However mortifying it may be to acknowledge 
 ignorance, variation of motion in a body cannot 
 be admitted as the cause of sensation universally ; 
 nor, as I said, can we comprehend anything of 
 the manner in which the nerves are affected; 
 certainly we know nothing of the manner in 
 which sensation is propagated or the mind ulti- 
 mately influenced. But there is a very pleasing 
 view of the subject* notwithstanding ; which is to 
 
 B. z
 
 198 OF TOUCH. 
 
 observe the correspondence of the mind (through 
 a series of organic parts) with the external world, 
 or with the condition and qualities of matter : 
 than which nothing can convey a more sublime 
 idea of Power, and of the system or unity of 
 organic and inorganic creations. 
 
 Returning to the consideration of the sensi- 
 bility of the skin and the sense of touch, this 
 property is as distinct an endowment as that 
 which belongs to the eye. It is neither inferior 
 nor more common. It is not consequent upon 
 the mere exposure of the delicate surface of the 
 animal body. It is a distinct sense, the organ 
 of which is seated in the skin ; and it is neces- 
 sary that this organ of sense should be extended 
 widely over the surface of the body. Yet the 
 nerves are as appropriate and distinct as if they 
 were gathered into one trunk, such as we find 
 them to be in the organs of vision and hearing. 
 
 Although the portion of nervous matter on 
 which the sensation of touch depends be neces- 
 sarily extended in its sentient extremities over 
 the whole exterior surface of the body, it is very 
 much concentrated towards the brain : and it is 
 there appropriated, in the same manner as the 
 nerves of vision and of hearing, to its peculiar 
 function of raising corresponding perceptions in 
 the mind. 
 
 Perhaps this will be better understood from 
 the fact that a certain large portion of the
 
 OF TOUCH. 199 
 
 skin may be the seat of excruciating pain, and 
 yet the surface, which to the patient's percep- 
 tion is the seat of that pain, will be altogether 
 insensible to cutting, burning, or any mode of 
 destruction ! "I have no feeling in all the side 
 " of my face, and it is dead ; yet surely it cannot 
 " be dead, since there is a constant pricking 
 " pain in it." Such were the words of a young 
 woman whose disease was at the root of the 
 nerve of sensibility near the brain.* The disease 
 destroyed the function of this nerve of the head, 
 as to its property of conveying sensation from 
 the exterior ; and substituted that morbid im- 
 pression on the trunk of the nerve, which was 
 referred to the tactile extremities. 
 
 If we use the term common sensibility, we 
 can do so only in reference to touch : as it is 
 the sense that is most necessary to animal ex- 
 istence; and as it is enjoyed by all animals 
 from the lowest to the highest in the chain of 
 existence. 
 
 Whilst this sense is distinct from the others, 
 it is the most important of all ; since through it 
 alone some animals possess the consciousness of 
 existence; and to those which enjoy many or- 
 gans of sense, that of touch, as we shall pre- 
 sently show, is necessary to the full develope- 
 ment of the powers of all the other organs. 
 
 * See papers by the author in the Philosophical Transactions.
 
 200 
 
 OF THE ORGAN OF TOUCH. 
 
 Touch is that peculiar sensibility which gives 
 the consciousness of the resistance of external 
 matter, and makes us acquainted with the hard- 
 ness, smoothness, roughness, size, and form of 
 bodies. It enables us to distinguish what is 
 external from what belongs to us ; and while it 
 informs us of the geometrical qualities of bodies, 
 we must refer to this sense also our judgment 
 of distance, of motion, of number, and of time. 
 
 Presuming that the sense of touch is exercised 
 by means of a complex apparatus by a combi- 
 nation of the consciousness of the action of the 
 muscles with the sensibility of the proper nerves 
 of touch, we shall, in the first place, examine 
 in what respect the organization resembles that 
 of the other senses. 
 
 We have said before that, on the most minute 
 examination of the extremity of a nerve, no 
 appropriate structure can be detected ; and that 
 the nerves expanded on the organs of sense 
 appear every where the same, soft, pulpy, pre- 
 pared for impression, and so distributed that the 
 impression shall reach them. What is termed 
 the structure of the organ of sense, is that 
 apparatus by which the external impression is 
 conveyed inwards, and by which its force is 
 concentrated on the extremity of the nerve.
 
 ORGAN OF TOUCH. 201 
 
 The mechanism by which those external organs 
 are suited to their offices, is highly interesting ; 
 it serves to shew (in a way that is level to our 
 comprehension, as most resembling things of 
 human contrivance) the design with which the 
 fabric is constructed. Thus, the eye is so seated 
 and so formed as to embrace the greatest pos- 
 sible field of vision ; we can understand the 
 happy effects of the convexity of the trans- 
 parent cornea, the influence of three humours 
 of various densities acting like an achromatic 
 telescope; we can admire the precision with 
 which the rays of light are concentrated on the 
 retina, and the beautiful provision for enlarging 
 or diminishing the pencil of light, in proportion 
 to its intensity. But all this explains nothing, 
 in respect to the perception that is excited in 
 the mind by the impulse on the extremity of the 
 nerve. 
 
 In like manner, in the complex apparatus of 
 the ear, we see how this organ is formed with 
 reference to a double course of impressions, as 
 they come through the solids or the body itself, 
 and as they come through the atmosphere ; we 
 comprehend how the undulations and vibrations 
 of the air are collected and concentrated ; how 
 they are directed, through the intricate passages 
 of the bone, to a fluid in which the nerve of 
 hearing is suspended ; and we see how, at last, 
 that nerve is moved. But we can comprehend
 
 202 ORGAN OF TOUCH. 
 
 nothing more from the study of the external 
 organ of hearing. 
 
 The illustration is equally clear in reference 
 to the organ of smelling, or of taste. There is 
 nothing in the nerve itself, either of the nose or 
 of the tongue, which can explain why it is sus- 
 ceptible of the particular impression. For these 
 reasons, we are prepared to expect very little 
 complexity in the organ of touch, and to believe 
 that the peculiarity of the sense consists more in 
 the property which has been bestowed on the 
 nerve, than in the mechanical adaptation of the 
 exterior organ. 
 
 OF THE CUTICLE. 
 
 The cuticle or epidermis covers the true skin, 
 excludes the air, limits the perspiration, and in 
 some degree regulates the heat of the body. 
 It is a dead or insensible covering; it guards 
 from contact the true vascular surface of the 
 skin ; and in this manner, it often prevents the 
 communication of infection. We are most fa- 
 miliar with it as that scarf skin which scales off 
 after fevers, or by the use of the flesh-brush, or 
 by the friction of the clothes ; for it is con- 
 tinually, separating in thin scales, whilst it is as 
 regularly formed anew by the vascular surface 
 below. The condition of this covering is inti- 
 mately connected with the organ of touch. The
 
 ORGAN OF TOUCH. 203 
 
 habit of considering things as produced acci- 
 dentally, has induced some anatomists to believe 
 that the cuticle is formed by the hardening of the 
 true skin. The fact, however, that the cuticle is 
 perfect in the new-born infant, and that even 
 then it is thickest on the hands and feet, should 
 have shewn that, like every thing in the animal 
 structure, it participates in the great design. 
 
 The cuticle is the organ of touch in this 
 respect, that it is the medium through which the 
 external impression is conveyed to the nerves of 
 touch ; and the manner in which this is accom- 
 plished is not without interest. The extremities 
 of the fingers exhibit all the provisions for the 
 exercise of this sense. The nails give support to 
 the fingers ; they are made broad and shield- 
 like,* in order to sustain the elastic cushion 
 which forms their extremity ; and the fulness 
 and elasticity of the ends of the fingers adapt 
 them admirably for touch. 
 
 The cushion on the end of the finger is a very 
 important part of the exterior apparatus. An in- 
 genious gentleman has observed that we cannot 
 feel the pulse at the wrist with the tongue. It 
 is a very remarkable fact, and I apprehend the 
 reason to be, not the insensibility of the tongue, 
 but the soft texture of it. It is not fitted to con- 
 vey the peculiar impulse, to which the firm and 
 
 * Unguis sctitifvrmis.
 
 '204 ORGAN OF TOUCH. 
 
 elastic pad of the finger is peculiarly suited. Is 
 it not interesting to find that we should posi- 
 tively lose one of our inlets to knowledge of 
 matter, were the organs of touch formed as 
 delicately as the tongue ! 
 
 But to return on a nearer inspection, we see 
 a more particular provision in the points of the 
 fingers. Wherever the sense of feeling is most 
 exquisite, there are minute spiral ridges of cu- 
 ticle. These ridges have, corresponding with 
 them, depressed lines on the inner surface of the 
 cuticle ; and these again give lodgment to a soft 
 pulpy matter, in which lie the extremities of the 
 sentient nerves. There the nerves are suffi- 
 ciently protected, while they are exposed to im- 
 pressions through the elastic cuticle, and thus 
 give the sense of touch. The organization is 
 simple, yet it is in strict analogy with the other 
 organs of sense. 
 
 Every one must have observed a tendency in 
 the cuticle to become thickened and stronger by 
 pressure and friction. If the pressure be partial 
 and severe, the action of the true skin is too 
 much excited, fluid is thrown out, and the 
 cuticle is raised in a blister. If it be still 
 partial, but more gradually applied, a corn is 
 formed. If, however, the general surface of the 
 palms or soles be exposed to pressure, the 
 cuticle thickens, until it becomes a defence like 
 a glove or a shoe. Now, what is most to be
 
 ORGAN OF TOUCH. 205 
 
 admired in this thickening of the cuticle is, 
 that the sense of touch is not lost, or indeed 
 diminished, certainly not at all in proportion 
 to the protection afforded by the thickening of 
 the skin. 
 
 The thickened cuticle partakes of the struc- 
 ture of the hoofs of animals : and we shall now 
 attend to the nature of the hoof, as the best pos- 
 sible illustration of the manner in which the sen- 
 sibility of the skin is in a due degree preserved 
 whilst the surface is guarded. 
 
 The human nail is a continuation of the 
 cuticle, and the hoof of an animal belongs to the 
 same class of parts. In observing the manner 
 in which the nerves enter the hoof, we have, in 
 fact, a magnified view of the structure which 
 exists, being only more minute and delicate, in 
 the cuticular covering of the fingers. We may 
 take the horse's foot as the example. When the 
 crust or hoof, which is insensible, is separated from 
 the part which, during life, possessed vascularity 
 and sensibility, we see small villi* hanging from 
 the vascular surface, and which have been with- 
 drawn from the crust ; looking to the inside of 
 the crust, we perceive the pores from which these 
 villi have been pulled. These processes from 
 the vascular surface are not merely extremities 
 
 * VILLI, delicate tufts, like the pile of velvet, projecting from 
 the surface of any membrane.
 
 20(5 ORGAN OK TOUCH. 
 
 of nerves ; they consist of the nerves with the 
 necessary accompaniment of membrane and 
 blood vessels, on a very minute scale. For it 
 must be remembered that nerves can perform no 
 function unless supplied with blood, all qualities 
 of life being supported through the circulating 
 blood. These nerves, so prolonged within the 
 villi into the hoof, receive the vibrations of that 
 body. By this means the horse is sensible to 
 the motion and pressure of its foot, or to its per- 
 cussion against the ground; and without this 
 provision, there would be a certain imperfection 
 in the limb. 
 
 In a former part of this treatise I have shewn 
 by what curious mechanism the horse's foot is 
 made yielding and elastic, for the purpose of 
 enabling it to bear the percussion against the 
 ground. But in made roads, and with the im- 
 perfections of shoeing, the pressure and con- 
 cussion are too severe and too incessant ; so that 
 the protecting sensibility of the foot is converted 
 into a source of pain from the inflammation 
 which arises ; and the horse is thus " foundered." 
 There is a remedy for this condition in dividing 
 the nerve across, before it reaches the foot ; the 
 consequence of which operation is, that the 
 horse, instead of moving with timid steps, puts 
 out his feet freely, and the lameness is cured. If, 
 however, we were to receive the statement thus 
 barely, the fact would militate against our con-
 
 ORGAN OF TOUCH. 207 
 
 elusion that mechanical provision and sensibility 
 go together, and that they are equally necessary 
 to the perfection of the instrument. We must 
 take into consideration this leading fact, that 
 pressure against the sole and crust is necessary 
 to the play of the foot and to its perfection. 
 When this part becomes inflamed, the animal 
 does not put its foot freely down, nor does it 
 bear its weight upon the hoof so as to bring all 
 the parts into action ; hence contraction is pro- 
 duced, the most common defect, as we before 
 said, of the horse's hoof. When the animal is 
 relieved from pain by the division of the nerve, 
 it uses the foot freely, and use restores all the 
 natural actions of this fine piece of mechanism. 
 It is obvious, however, that there is a certain 
 defect ; the horse has lost his natural protection, 
 and must now be indebted to the care of his 
 rider. He has not only lost the pain which 
 should guard against over exertion, but the feel- 
 ing of the ground, which is necessary to his 
 being perfectly safe as a roadster. 
 
 The teeth are provided with sensibility much 
 in the same manner as the hoof of the horse is. 
 Although the bone and enamel have no sensi- 
 bility, yet a branch of a sensible nerve (the 
 fifth) enters into the cavity of every tooth, and 
 the vibration being communicated through the 
 tooth to the nerve, the smallest grain is felt 
 between the teeth.
 
 208 ORGAN OF TOUCH. 
 
 But, to return to the human hand ; in the 
 fingers and palm of a man who uses the fore- 
 hammer, the cuticle is thickened in a remark- 
 able manner. The depressed lines, however, in 
 its inner surface become deeper, and the villi 
 projecting into them longer; which, joined to 
 the aptitude of the cuticle to convey the impres- 
 sion to those included nerves, leaves him in pos- 
 session of the sense of touch in a very high 
 degree. 
 
 In the foot of the ostrich we have a magnified 
 view of the thickened cuticle and the lengthened 
 nerves. This outer skin of its foot almost equals 
 in thickness the hoof of the solidungula, and 
 when it is separated from the sensible sole, the 
 villi, or papillaB, having in them the sensible 
 nerves, are withdrawn, leaving corresponding 
 foramina or pores in the sole. We perceive 
 that if the object had been merely to cover and 
 protect the foot, it would have been sufficient 
 to have invested it with a succession of solid and 
 dead layers of cuticle. This would have been 
 the case had the cuticle been merely thickened 
 by pressure, and had there been no design to 
 make a provision adapted in all respects to the 
 habits of the bird. 
 
 Such, then, is the structure of the organ of 
 touch : obvious in the extremities of the fingers ; 
 magnified in the foot of the horse or of the
 
 ORGAN OF TOUCH. 209 
 
 ostrich ; and existing even in the delicate skin 
 of the lips. 
 
 I have casually noticed that increased vascu- 
 larity is always an accompaniment of nerves, 
 and necessary to the sensibility of a part. In 
 the museum of the College of Surgeons we see 
 that Mr. Hunter had taken the pains to demon- 
 strate this, by the injection of the blood-vessels 
 of a slug. Although fluid was injected from its 
 heart, the blush from the vermilion extends over 
 its foot ; the foot, in these gasteropoda, being 
 the whole lower flat surface on which the animal 
 creeps. This surface is also the organ of touch, 
 by which it feels and directs its motions. It 
 is on the same principle, if we may compare 
 such things, that we explain the rosy tipped 
 fingers and the ruby lips, which imply fine sen- 
 sibility combined with high vascularity. 
 
 Having described the relation of the cuticle 
 to the nerves of touch, we may take notice of 
 another quality, its roughness, and of the ad- 
 vantages accruing from this. In the first place, 
 as to the subserviency of this quality to feeling, 
 we must be sensible that in touching a finely 
 polished surface the organ is but imperfectly 
 exercised, as compared with its condition when 
 we touch or grasp a rough and irregular body. 
 Had the cuticle been finely polished on its sur- 
 face, it would have been but ill suited to touch :
 
 210 ORGAN OF TOUCH. 
 
 on the contrary, it has a very peculiar rough- 
 ness which adapts it to feeling. A provision for 
 friction, as opposed to smoothness, is a neces- 
 sary quality of some parts of the skin ; thus the 
 roughness of the cuticle has the advantage of 
 giving us a firmer grasp, and a steadier footing. 
 Nothing is so little apt to slip as the thickened 
 cuticle of the hand or foot. In the hoofs of 
 animals, as might be expected, this structure is 
 further developed. The chamois, ibex, or goat, 
 steps securely on the ledges of rocks and at 
 great heights, where it would seem impossible 
 to cling. On the pads or cushions of the cat, 
 the cuticle is rough and granular ; and in the 
 foot of the squirrel, indeed of all animals which 
 climb, those pads covered with the peculiar tex- 
 ture of the cuticle, give security in descending, 
 as their claws enable them to grasp and cling. 
 
 In concluding this section, we perceive that 
 the organ of touch consists of nerves appro- 
 priated to receive the impressions of bodies 
 which are capable of offering resistance. Fine 
 filaments of those nerves, wrapt up in delicate 
 membrane with their accompanying arteries and 
 veins, project from the true skin into correspond- 
 ing grooves or foramina of the cuticle. They 
 are not absolutely in contact with the cuticle, 
 but are surrounded with a semi-fluid matter. 
 By this fluid and by the cuticle they are pro- 
 tected, at the same time that they are sensible
 
 ORGAN OF TOUCH. 21 1 
 
 to the pressure made on the surface, and to 
 cutting, pricking, and heat.* But this capa- 
 city, we repeat, is not owing, strictly speaking, 
 to any thing in the structure of the organ, but 
 to the appropriation of the nerve to this class of 
 sensations. 
 
 * It is a curious confirmation of the fact, that the cutaneous 
 nerve is adapted to receive impressions from the varieties of tem- 
 perature, that when disease takes place in the centre of the trunk 
 of a nerve, or when the nerve is surrounded with diseased parts, 
 the sensation of burning accompanies the pain ; and the patient 
 refers this to the part of the skin to which the extreme branch 
 of the nerve is distributed. By a burning sensation in the sole 
 of the foot, I have been directed to disease seated in the centre 
 of the thigh.
 
 212 
 
 CHAPTER IX. 
 
 OF THE MUSCULAR SENSE. 
 
 Of the Sensibility of the Infant to Impressions, 
 and the gradual Improvement of the Sense of 
 Touch. 
 
 A NOTION prevails that the young of animals are 
 directed by instinct, but that there is an excep- 
 tion in regard to the human offspring : that in 
 the child we have to trace the gradual dawn 
 and progressive improvement of reason. This 
 is not quite true ; we doubt whether the body 
 would ever be exercised under the influence of 
 reason alone, and if it were not first directed by 
 sensibilities which are innate or instinctive. 
 
 The sensibilities and the motions of the lips 
 and tongue are perfect from the beginning ; and 
 the dread of falling is shewn in the young infant 
 long before it can have had experience of vio- 
 lence of any kind. 
 
 The hand, which is to become the instrument 
 for perfecting the other senses and developing 
 the endowments of the mind itself, is in the 
 infant absolutely powerless. Pain is poetically
 
 OF THE MUSCULAR SENSE. 213 
 
 described as that power into whose " iron grasp" 
 we are consigned, to be introduced to a material 
 world; now, although the infant is capable of 
 an expression of pain, which cannot be mis- 
 understood, and is the same which accompanies 
 all painful impressions during the whole life, yet 
 it is unconscious of the part of the body which 
 suffers. We have again recourse to the sur- 
 geon's experience. There occur certain con- 
 genital imperfections which require an opera- 
 tion at this early stage of life ; but the infant 
 makes no direct effort with its hand to repel the 
 instrument, or to disturb the dressing, as it will 
 at a period somewhat later. 
 
 The lips and tongue are first exercised; the 
 next motion is to put the hand to the mouth, 
 in order to suck it : and no sooner are the 
 fingers capable of grasping, than whatever they 
 hold is carried to the mouth. So that the sen- 
 sibility to touch in the lips and tongue, and their 
 motions, are the first inlets to knowledge ; and 
 the use of the hand is a later acquirement. 
 
 The knowledge of external bodies as distin- 
 guished from ourselves, cannot be acquired until 
 the organs of touch in the hand have become 
 familiar with our own limbs ; we cannot be sup- 
 posed capable of exploring any thing by the 
 motion of the hand, or of judging of the form or 
 tangible qualities of an object pressed against 
 the skin, before we have a knowledge of our 
 B. A A
 
 214 OF THE MUSCULAR SENSE. 
 
 own body as distinguished from things external 
 to us. 
 
 The first office of the hand, then, is to exer- 
 cise the sensibility of the mouth : and the infant 
 as certainly questions the reality of things by 
 that test, as the dog does by its acute sense of 
 smelling. In the infant, the sense of the lips 
 and tongue is resigned in favour of the sense of 
 vision, only when that sense has improved and 
 offers a greater gratification, and a better means 
 of judging of the qualities of bodies. The 
 hand very slowly acquires the sense of touch, 
 and many ineffectual efforts are seen, in the 
 arms and fingers of the child, before the direc- 
 tion of objects or their distance is ascertained. 
 Gradually the length of the arm, and the extent 
 of its motions become the measure of distance, 
 of form, of relation, and perhaps of time. 
 
 Next in importance to the sensibility of the 
 mouth, we may contemplate that sense which 
 is early exhibited in the infant, the terror of 
 falling. The nurse will tell us that the infant 
 lies composed while she carries it in her arms 
 up stairs ; but that it is agitated in carrying it 
 down. If an infant be laid upon the arms and 
 dandled up and down, its body and limbs will 
 be at rest, whilst it is raised ; but they will 
 struggle and make an effort, as it descends. 
 There is here the indication of a sense, an 
 innate feeling of danger, the influence of which
 
 OF THE MUSCULAR SENSE. 215 
 
 we may perceive when the child first attempts 
 to stand or run. When the child is set upon its 
 feet, and the nurse's arms form a hoop around 
 it without touching it, it slowly learns to balance 
 itself and stand ; but under a considerable ap- 
 prehension. Presently, it will stand at such a 
 distance from the nurse's knee, that if it should 
 lose its balance, it can throw itself for protection 
 into her lap. In these its first attempts to use 
 its muscular frame, it is directed by an appre- 
 hension which cannot as yet be attributed to 
 experience. By degrees it acquires the know- 
 ledge of the measure of its arm, the relative 
 distance to which it can reach, and the power of 
 its muscles. Children, therefore, are cowardly 
 by instinct : they show an apprehension of fall- 
 ing ; and we may gradually trace the efforts 
 which they make, under the guidance of this 
 sensibility, to perfect the muscular sense. In 
 the mean time, we perceive how instinct and 
 reason are combined in early infancy : how 
 necessary the first is to existence : how it is 
 subservient to reason : and how it yields to the 
 progress of reason, until it becomes so obscured 
 that we can hardly discern its influence. 
 
 When treating of the senses, and showing how 
 one organ profits by the exercise of the other, 
 and how each is indebted to that of touch, I was 
 led to observe that the sensibility of the skin is 
 the most dependant of all on the exercise of
 
 210 OF THE MUSCULAR SENSE. 
 
 another quality. Without a sense of muscular 
 action or a consciousness of the degree of effort 
 made, the proper sense of touch could hardly be 
 an inlet to knowledge at all. I am now to show 
 that the motion of the hand and fingers, and the 
 sense or consciousness of their action, must be 
 combined with the sense of touch, properly so 
 called, before we can ascribe to it the influence 
 which it possesses over the other organs. 
 
 In my general course of lectures on anatomy, 
 I ventured on this explanation from the com- 
 mencement; much doubting, however, the cor- 
 rectness of my reasoning, from seeing that the 
 great authorities on this subject made no ac- 
 count of the knowledge derived from the motions 
 of our own frame. I called this consciousness 
 of muscular exertion a sixth sense ; considering 
 it as essential to the exercise of the sense of 
 touch. I can now refer, in confirmation of this 
 view, to the works of philosophers who have 
 been educated to medicine; and to whom the 
 necessity of the combination of the two faculties 
 had suggested itself as it had to me.* Those 
 distinctions were connected with my enquiries 
 into the functions of the nervous system, and in 
 some measure directed them.f 
 
 . . j ': ..}-/... j ; . . . - , . > 
 
 * See Dr. Brown's Lectures on Moral Philosophy. 
 
 | It was this conviction that we are sensible of the action of 
 the muscles, which led me to the investigation of their nerves ; 
 first, by anatomy, and then by experiment. I was finally enabled
 
 OF THE MUSCULAR SENSE. 217 
 
 The Abbe Nollet, after extolling the sense of 
 touch as superior to all the other senses, and as 
 deserving to be considered the genus under 
 which the others should be included as subordi- 
 nate species, makes this remark " Besides, it 
 " has this advantage over them, to be at the 
 " same time both active and passive : for it not 
 " only puts it in our power to judge of what 
 " makes an impression upon us, but likewise of 
 
 to show that the muscles had two classes of nerves that on 
 exciting one of these, the muscle contracted : that on exciting 
 the other, no action took place. The nerve which had no power 
 to make the muscle contract was found to be a nerve of sensa- 
 tion. Thus, it was proved that there is a nervous circle con- 
 necting the muscles with the brain : that one nerve is not capable 
 of transmitting what is called the nervous spirits, in two different 
 directions at one instant of time ; but that for the regulation of 
 muscular action, there is a nerve of sensibility to convey a sen- 
 sation of the condition of the muscles to the sensorium, as well 
 as a nerve of motion for conveying the mandate of the will to 
 the muscles. In their distribution through the body, the nerves 
 which possess these two distinct powers, of conveying sensation 
 and of exciting the muscles to contraction, are wrapped up, or, 
 as it were, woven together in the same sheath ; and they present 
 to the eye the appearance of one nerve. It was only by exa- 
 mining the nerves at their roots, that is, where they arise from 
 different tracts of the brain and spinal marrow, and before they 
 have coalesced, that I succeeded in demonstrating their distinct 
 functions. In the face, the nerve of motion passes by a cir- 
 cuitous course, apart from the nerve of sensation, to be dis- 
 tributed to the muscles ; and therefore the distinct characters of 
 these two nerves were more easily proved by experiment than in 
 any other part of the body. See the Philosophical Transactions, 
 on the " Nervous Circle which connects the Voluntary Muscles 
 with the Brain," and the " Nervous System." 4to. Longman.
 
 218 OF THE MUSCULAR SENSE. 
 
 " what resists our impulsions." The mistake 
 here lies in giving to the nerves of touch a pro- 
 perty which must belong to the actions of mus- 
 cles. So it is affirmed by physiologists, as I 
 have already had occasion to state, that the 
 sense of touch differs from the other senses by 
 this circumstance that an effort is propagated 
 towards it, as well as a sensation received from 
 it. This confusion obviously arises from con- 
 sidering the muscular agency, which is directed 
 by the will during the exercise of touch, as 
 belonging to the nerve of touch properly. V^e 
 proceed to show how the sense of motion and 
 that of touch are necessarily combined. 
 
 When a blind man, or a man with his eyes 
 shut, stands upright, neither leaning upon, nor 
 touching aught; by what means is it that he 
 maintains the erect position ? The symmetry of 
 his body is not the cause. The statue of the 
 finest proportion must be soldered to its pedes- 
 tal, or the wind will cast it down. How is it, 
 then, that a man sustains the perpendicular 
 posture, or inclines in due degree towards the 
 winds that blow upon him? It is obvious that 
 he has a sense by which he knows the inclina- 
 tion of his body, and that he has a ready apti- 
 tude to adjust it, and to correct any deviation 
 from the perpendicular. What sense then is 
 this? for he touches nothing, and sees nothing ; 
 there is no organ of sense hitherto observed
 
 OF THE MUSCULAR SENSE. 219 
 
 which can serve him, or in any degree aid him. 
 Is it not that sense which is exhibited so early 
 in the infant, in the fear of falling ? Is it not 
 the full developement of that property which 
 was early shown in the struggle of the infant 
 while it yet lay in the nurse's arms? It can 
 only be by the adjustment of muscles that the 
 limbs are stiffened, the body firmly balanced 
 and kept erect. There is no other source of 
 knowledge, but a sense of the degree of exer- 
 tion in his muscular frame, by which a man can 
 know the position of his body and limbs, while 
 he has no point of vision to direct his efforts, 
 or the contact of any external body. In truth, 
 we stand by so fine an exercise of this power, 
 and the muscles are, from habit, directed with 
 so much precision and with an effort so slight, 
 that we do not know how we stand. But if we 
 attempt to walk on a narrow ledge, or stand in a 
 situation where we are in danger of falling, or 
 rest on one foot, we become then subject to 
 apprehension : the actions of the muscles are, 
 as it were, magnified and demonstrative of the 
 degree in which they are excited. 
 
 We are sensible of the position of our limbs ; 
 we know that the arms hang by the sides ; or 
 that they are raised and held out ; although we 
 touch nothing and see nothing. It must be a 
 property internal to the frame by which we 
 thus know the position of the members of our
 
 220 OF THE MUSCULAR SENSE. 
 
 body : and what can this be but a consciousness 
 of the degree of action, and of the adjustment of 
 the muscles? At one time, I entertained a doubt 
 whether this proceeded from a knowledge of the 
 condition of the muscles or from a conscious- 
 ness of the degree of effort which was directed to 
 them in volition. It was with a view to eluci- 
 date this, that I made the observations which 
 terminated in the discovery that every muscle 
 had two nerves one for sensation, and one to 
 convey the mandate of the will and direct its 
 action. I had reasoned in this manner we 
 awake with a knowledge of the position of our 
 limbs : this cannot be from a recollection of the 
 action which placed them where they are; it 
 must, therefore, be a consciousness of their pre- 
 sent condition. When a person in these circum- 
 stances moves, he has a determined object ; and 
 he must be conscious of a previous condition be- 
 fore he can desire a change or direct a move- 
 ment. 
 
 After a limb has been removed by the sur- 
 geon, the person still feels pain, and heat, and 
 cold in it. Urging a patient to move who has 
 lost his limb, I have seen him catch at the limb 
 to guard it, forgetful that it was removed ; and 
 long after his loss, he experiences a sensation not 
 only as if the limb remained, but as if it were 
 placed or hanging in a particular position or 
 posture. I have asked a patient " Where do
 
 OF THE MUSCULAR SENSE. 221 
 
 " you feel your arm now ?" and he has said, " I 
 " feel it as if it lay across my breast," or that it 
 is " lying by my side." It seems also to change 
 with the change of posture of the body. These 
 are additional proofs of a muscular sense ; that 
 there is an internal sensibility corresponding 
 with the changing condition of the muscles ; and 
 that as the sensations of an organ of sense 
 remain after the destruction of the outward 
 organ, so here a deceptions sensibility to the 
 condition of the muscles, as well as to the con- 
 dition of the skin, is felt after the removal of the 
 limb. 
 
 By such arguments I have been in the habit 
 of showing that we possess a muscular sense, 
 and that without it we could have no guidance of 
 the frame. We could not command our muscles 
 in standing, far less in walking, leaping, or 
 running, had we not a perception of the con- 
 dition of the muscles previous to the exercise 
 of the will. And as for the hand, it is not more 
 the freedom of its action which constitutes its 
 perfection, than the knowledge which we have 
 of these motions, and our consequent ability to 
 direct it with the utmost precision. 
 
 The necessity for the combination of two 
 distinct properties of the nervous system in the 
 sense of touch becomes more obvious, if we 
 examine their operation in another but ana- 
 logous organ ; for example, in the palpa or
 
 222 OF THE MUSCULAR SENSE 
 
 tentacula of the lower animals. These animals 
 use those instruments to grope their way : and 
 they consist of a rigid tube containing a pulpy 
 matter, in which there is a branch of a nerve 
 that possesses, in an exquisite degree, the sense 
 of touch. Now when this instrument touches a 
 body and the vibration runs along the pulp of 
 the nerve, the animal can be sensible only of an 
 obstruction : but where is that obstruction, and 
 how is the creature's progress to be directed to 
 avoid it ? We must acknowledge that the instru- 
 ment moves about and feels on all sides, and 
 that it is the action of the muscles moving this 
 projecting instrument, and the sense of their 
 activity, which convey the knowledge of the 
 place or direction of the obstructing body. It 
 appears, therefore, that even in the very lowest 
 creatures, the sense of touch implies the compa- 
 rison of two distinct senses. 
 
 That insects have the most exquisite organs 
 of sense must be allowed : but we do not reflect 
 on the extraordinary accuracy with which in 
 their movements they measure distances. This 
 can only be an adaptation of the muscular exer- 
 tion to the sense of vision. The spider which I 
 have already alluded to in a former chapter the 
 aranea scenica, when about to leap, elevates itself 
 upon its fore legs, and lifting its head, seems to 
 survey the spot before it jumps. When this 
 insect spies a small gnat or fly upon the wall, it
 
 IN THE LOWER ANIMALS. 2*23 
 
 creeps very gently towards it, with short steps, 
 till it comes within a proper distance, and then 
 it springs suddenly like a tiger. It will jump 
 two feet to seize upon a bee.* 
 
 We have a more curious instance of the pre- 
 cision of the eye and of the adaptation of mus- 
 cular action, in the chcetodon rostratus.^ This 
 fish inhabits the Indian rivers, and lives on 
 
 the smaller aquatic flies. When it observes 
 one alighted on a twig, or flying near (for it 
 can shoot them on the wing) it darts a drop of 
 water with so steady an aim as to bring the fly 
 down into the water, when it falls an easy prey. 
 These fishes are kept in large vases for amuse- 
 ment, and if a fly be presented on the end of a 
 twig, they will shoot at it with surprising accu- 
 racy. In its natural state it will hit a fly at the 
 distance of from three to six feet. The zeus in- 
 sidiator\ has also the power of forming its mouth 
 into a tube and squirting at flies so as to en- 
 
 * Kirby. 
 
 t Choetodon, a genus of the Acanthopterygii. 
 
 % Belonging to another genus of the same Order.
 
 224 OF THE MUSCULAR SENSE. 
 
 cumber their wings and bring them to the sur- 
 face of the water. Whether led to admire the 
 wonderful power of instinct in these inferior 
 creatures, or the property acquired by our own 
 eye, we must acknowledge here a compound 
 operation.* 
 
 The impression of odours on the nerve of 
 smelling is exactly what some would have us to 
 believe the effect of light is on the nerve of 
 vision ; and yet, the impression on the nerve of 
 vision alone is sufficient, in their opinion, to 
 inform us of all that we know through the eye. 
 Now of the direction and distance from which 
 odours come we are quite ignorant, until by 
 turning the head and directing the nostrils, and 
 moving this way and that, we make comparison, 
 and discover on which side the smell is strongest 
 on the sense. 
 
 The property of motion in the body is, in 
 insects, rendered subservient to smelling, as 
 well as to vision. There can be nothing in the 
 mere exercise of the organ of smelling to direct 
 the insect in its flight. If a piece of carrion be 
 thrown out, the flies approach it, not hi 
 a direct line, but by coming in circles, towards 
 it ; and so do the bees, in a garden, when 
 
 * In these instances a difficulty will readily occur to the 
 reader; how does the fish judge of position, since the rays of 
 light are refracted at the surface of the water ? Does instinct 
 enable it to do this, or is it by experience ?
 
 OF THE MUSCULAR SENSE. 225 
 
 attracted to a flower. They may be seen, at 
 first, flying wide, and then each circle diminish- 
 ing as they come near, until they at last alight 
 upon the object. It is from the sense of the 
 odour being more acute in one part of the circle, 
 that the next wheel is made ; and thus they are 
 directed in their flight, as it were in a line 
 drawn through these circles. 
 
 We can judge of the direction of sounds with- 
 out turning the head, because the strength of vi- 
 bration is unequal on the two sides of the head, 
 and a comparison is thus made of the two im- 
 pressions. But when a person is deaf in one ear 
 the operation is difficult ; he is often mistaken 
 as to the direction of sounds, and he has more 
 necessity to turn the head and to compare the 
 position of the tube of the ear with the strength 
 of the impressions. Accordingly, in mixed com- 
 pany, where there are many speakers, he ap- 
 pears positively deaf, from the impossibility of 
 distinguishing minutely the direction of sounds. 
 
 The last proof of the necessity of the combi- 
 nation of the muscular sense with the sense of 
 contact will be conclusive. The following is not 
 a solitary instance : 
 
 A mother while nursing her infant was seized 
 with a paralysis, attended by the loss of power 
 on one side of her body and the loss of sensi- 
 bility on the other side. The surprising, and, 
 indeed, the alarming circumstance here was,
 
 220 THE LOSS OF SENSIBILITY AND 
 
 that she could hold her child to her bosom with 
 the arm which possessed muscular power, but 
 only as long as she looked to the infant. If sur- 
 rounding objects withdrew her attention from 
 the state of her arm, the flexor muscles gra- 
 dually relaxed and the child was in danger of 
 falling. The details of the case do not belong 
 to our present enquiry; but we see here, first, 
 that there are two properties in the arm : which 
 is shown by the loss of the one and the con- 
 tinuance of the other ; secondly, that these pro- 
 perties exist through different conditions of the 
 nervous system ; and, thirdly, we perceive how 
 ineffectual to the exercise of the limbs is the 
 continuance of the muscular power, without the 
 sensibility which should accompany and di- 
 rect it. 
 
 The property in the hand of ascertaining the 
 distance, the size, the weight, the form, the 
 hardness or softness, the roughness or smooth- 
 ness of objects, results from there being this 
 combined perception from the sensibility of the 
 proper organ of touch being combined with the 
 consciousness of the motion of the arm, hand, 
 and fingers. But the motion of the fingers is 
 especially necessary to the sense of touch. 
 These bend, extend, or expand, moving in all 
 directions like palpa, with the advantage of em- 
 bracing the object, and feeling it on all its sur-
 
 THE MUSCULAR POWER REMAINING. 227 
 
 faces, sensible to its solidity and to its resistance 
 when grasped, moving round it and gliding over 
 its surfaces, and, therefore, feeling every aspe- 
 rity, and every the slightest vibration. 
 
 THE PLEASURES ARISING FROM THE 
 MUSCULAR SENSE. 
 
 :.,;U>,^> *(H^ ftV 
 
 The exercise of the muscular frame is the 
 source of much of the knowledge which is 
 usually supposed to be obtained through the 
 organs of the senses ; and to this source, also, 
 we must trace some of our chief enjoyments. 
 We may, indeed, affirm that it is benevolently 
 provided that the vigorous circulation of the 
 blood, and, therefore, the healthful condition 
 both of the mind and the body shall result from 
 muscular exertion and the alternations of acti- 
 vity and repose. 
 
 The pleasure which arises from the activity of 
 the body is also attended by gratification from 
 the exercise of a species of power as that which 
 mere dexterity, successful pursuit in the field, or 
 the accomplishment of some work of art may 
 give. This activity is followed by weariness 
 and a desire for rest : and although unattended 
 with any describable pleasure or local sensation, 
 there is diffused through every part of the frame
 
 228 PLEASURES ARISING 
 
 after fatigue and whilst the active powers are 
 sinking into repose, a feeling almost voluptuous. 
 To this feeling the impatience of rest succeeds ; 
 and thus we are urged to the alternations which 
 are necessary to health, and are invited on from 
 stage to stage of our existence. 
 
 We owe other enjoyments to the muscular 
 sense. It would appear that in modern times 
 we know comparatively little of the pleasures 
 arising from motion. The Greeks, and even the 
 Romans, studied elegance of attitude and of 
 movement. Their apparel admitted of it, and 
 their exercises and games must have led to it. 
 Their dances were not the result of mere ex- 
 uberance of spirits and activity ; they combined 
 harmony in the motion of the body and limbs, 
 with majesty of gait. They consisted more of 
 the unfolding of the arms than of the play of 
 the feet, " Their arms sublime that floated on 
 the air." The Pyrrhic dances were elegant 
 movements, joined to the attitudes of combat, 
 and performed in correct coincidence with the 
 expression of the music. The spectators in their 
 theatres must have had very different associa- 
 tions from ours, to account for the national en- 
 thusiasm arising from music and their rage 
 excited by a mere error in the time. 
 
 This may remind us that the divisions in 
 music in some degree belong to the muscular 
 sense. A man will put down his staff in regu-
 
 FROM THE MUSCULAR SENSE. 229 
 
 lated time, and the sound of his steps will fall 
 into a measure, in his common walk. A boy 
 striking the railing in mere wantonness, will do 
 it with a regular succession of blows. This 
 disposition of the muscular frame to put itself 
 into motion with an accordance to time is the 
 source of much that is pleasing in music, and 
 aids the effect of melody. There is thus esta- 
 blished the closest connection between the enjoy- 
 ments of the sense of hearing and the exercise 
 of the muscular sense.* 
 
 * To learn how much the enjoyment of the sense of vision 
 belongs to motion, see the " Additional Illustrations," at the end 
 of the volume. 
 
 B. B B
 
 '230 
 
 CHAPTER X. 
 
 THE HAND NOT THE SOURCE OF INGENUITY OR 
 CONTRIVANCE, NOR CONSEQUENTLY OF MAN's 
 SUPERIORITY. 
 
 SEEING the perfection of the hand, we can 
 hardly be surprised that some philosophers 
 should have entertained the opinion with An- 
 axagoras, that the superiority of man is owing 
 to his hand. We have seen that the system of 
 bones, muscles, and nerves of this extremity is
 
 SOURCE OF SUPERIORITY. 231 
 
 suited to every form and condition of vertebrated 
 animals ; and we must confess that it is in the 
 human hand that we have the consummation of 
 all perfection as an instrument. This, we per- 
 ceive, consists in its power, which is a combi- 
 nation of strength with variety and extent of 
 motion ; we see it in the forms, relations, and 
 sensibility of the fingers and thumb ; in the 
 provisions for holding, pulling, spinning, weav- 
 ing, and constructing ; properties which may be 
 found in other animals, but which are combined 
 to form this more perfect instrument. 
 
 In these provisions, the instrument corresponds 
 with the superior mental capacities, the hand 
 being capable of executing whatever man's in- 
 genuity suggests. Nevertheless, the possession 
 of the ready instrument is not the cause of the 
 superiority of man, nor is its aptness the mea- 
 sure of his attainments. So, we rather say with 
 Galen that man had hands given to him be- 
 cause he was the wisest creature, than ascribe 
 his superiority and knowledge to the use of his 
 hands.* 
 
 This question has arisen from observing the 
 
 * Ita quidem sapientissimum animalium est homo : ita autem 
 et manus sunt organa sapient! animali convenientia. Non enim 
 quia manus habuit propterea est sapientissimum, ut Anaxagoras 
 dicebat : sed quia sapientissimum erat, propter hoc manus habuit, 
 ut rectissime censuit Aristoteles. Non enim manus ipsae homines 
 artes docuerunt, sed ratio. Manus autem ipsse sunt artium or- 
 gana : sicut lyra, musici, et forceps, fabri.
 
 232 THE HAND NOT THE 
 
 perfect correspondence between the propensities* 
 of animals and their forms and outward organi- 
 zation. When we see a heron standing by the 
 water side, still as a grey stone, and hardly dis- 
 tinguishable from it, we may ascribe this habit 
 to the acquired use of its feet, constructed for 
 wading, and to its long bill and flexible neck ; 
 for the neck and bill are as much suited to its 
 wants as the Hester is to the fisherman. But 
 there is nothing in the configuration of the 
 black-bear particularly adapted to catch fish ; 
 yet he will sit on his hinder extremities by the 
 side of a stream, in the morning or evening, like 
 a practised fisher ; there he will watch, so mo- 
 tionless as to deceive the eye of the Indian, who 
 mistakes him for the burnt trunk of a tree ; and 
 with his fore paw he will seize a fish with in- 
 credible celerity. The exterior organ is not, in 
 this instance, the cause of the habit or of the 
 propensity; and if we see the animal in pos- 
 session of the instinct without the appropriate 
 organ, we can the more readily believe that, in 
 other examples, the habit exists with the instru- 
 ment, although not through it. 
 
 The canine teeth are not given without the 
 carnivorous appetite, nor is the necessity of 
 living by carnage joined to a timid disposition ; 
 but boldness and fierceness, as well as cunning, 
 belong to the animal with retractile claws and
 
 SOURCE OF INGENUITY. 233 
 
 sharp teeth, and which prey on living animals.* 
 On the other hand, the propensities of the timid 
 vegetable feeder are not produced by the erect 
 ears and prominent eyes : though his suspicious- 
 ness and timidity correspond with them. The 
 boldness of the bison or buffalo may be as great 
 as that of the lion ; but the impulse is different 
 there is a direction given to them by instinct 
 to strike with their horns : and they will so push 
 whether they have horns or not. " The young 
 " calf will butt against you before he has horns," 
 says Galen : and the Scotch song has it, " the 
 " putting cow is ay a doddy," that is, the 
 humble cow (inermis), although wanting horns, 
 is always the most mischievous. When that 
 noble animal, the Brahmin bull, of the Zoolo- 
 gical Gardens, first put his hoof on the sod 
 and smelt the fresh grass after his voyage, 
 placid and easily managed before, he became 
 excited, plunged, and struck his horns into the 
 earth, and ploughed up the ground on alternate 
 sides, with a very remarkable precision. This 
 was his dangerous play ; just as the dog, in his 
 gambols, worries and fights : or the cat, though 
 pleased, puts out its claws. It would, indeed, 
 
 * In some of the quadrumana, the canine teeth are as long 
 and sharp as those of the tiger but in them they are only 
 instruments of defence, and have no relation to the appetite, or 
 mode of digestion, or internal organization. 
 
 B. C C
 
 234 INSTINCT OF THE 
 
 be strange, where all else is perfect, if the 
 instinctive character or disposition of the animal 
 were at variance with its arms or instruments. 
 
 But the idea may still be entertained that the 
 accidental use of the organ may conduce to its 
 more frequent exercise and to the production of 
 a corresponding disposition. Such an hypo- 
 thesis would not explain the facts. The late 
 Sir Joseph Banks, in his evening conversations, 
 told us that he had seen, what many perhaps 
 have seen, a chicken catch at a fly whilst the 
 shell stuck to its tail. Sir Humphrey Davy 
 relates that a friend of his, having discovered 
 under the burning sand of Ceylon the eggs of 
 an alligator, had the curiosity to break one 
 of them ; when a young alligator came forth, 
 perfect in its motions and in its passions; for 
 although hatched under the influence of the 
 sunbeams, in the sand, it made towards the 
 water, its proper element : when hindered, it 
 assumed a threatening aspect and bit the stick 
 presented to it. As propensities to certain mo- 
 tions, to which their external organs are subser- 
 vient, are implanted in animals, so are passions 
 given as the means of their defence or of obtain- 
 ing food. But this has been well said seventeen 
 hundred years ago. " Take," says Galen, " three 
 " eggs, one of an eagle, another of a goose, and 
 " a third of a viper ; and place them favourably
 
 YOUNG ANIMAL. 235 
 
 " for hatching. When the shells are broken, 
 " the eaglet and the gosling will attempt to fly ; 
 " while the young of the viper will coil and 
 " twist along the ground. If the experiment be 
 " protracted to a later period, the eagle will 
 " soar to the highest regions of the air, the goose 
 " betake itself to the marshy pool, and the viper 
 " will bury itself in the ground." 
 
 We have, daily, before us the proofs of inge- 
 nuity in the arts, not only surviving the loss of 
 the hand, but excited and exercised where there 
 were no such instruments from birth. What is 
 more surprising than to see the feet, in such indi- 
 viduals becoming substitutes for the hands, and 
 working minute and curious things? Unfortu- 
 nately too, the most diabolical passions will in 
 some natures be developed, and crimes com- 
 mitted where we might have supposed it impos- 
 sible, from the power of execution being denied. 
 Of this the most remarkable instance was in a 
 man who from birth had no arms, like the unfor- 
 tunate youth described in the early part of the 
 volume, but who, as if possessed of a devil, had 
 committed many murders before he was dis- 
 covered and executed. This wretch was a beg- 
 gar, who took his stand on the high way some 
 miles from Moscow, on the skirts of a wood. 
 His manner was to throw his head against the 
 stomach of the person who was in the act of
 
 23f> THE SUBJECT ILLUSTRATED 
 
 giving him charity, and having stunned him, to 
 seize him with his teeth and so drag him into the 
 wood ! 
 
 But to turn to a more agreeable part of our 
 subject. With the possession of an instrument 
 like the hand, there must be a great part of the 
 organization which strictly belongs to it, con- 
 cealed. The hand is not a thing appended, or 
 put on, like an additional movement in a watch ; 
 but a thousand intricate relations must be esta- 
 blished throughout the body in connection with 
 it ; such as nerves of motion and nerves of sensa- 
 tion : there must be an original part of the 
 composition of the brain which shall have re- 
 lation to these new parts, before they can be put 
 into activity : and even with all this superadded 
 organization, the hand would lie inactive, unless 
 there were created a propensity to put it into 
 operation. 
 
 Voltaire has said that Newton, with all his 
 science, knew not how his arm moved ! So true 
 it is that all such studies have their limits. 
 But, as he acknowledges, there is a wide 
 difference between the ignorance of the child 
 or of the peasant, and the consciousness of the 
 philosopher that he has arrived at a point 
 beyond which man's faculties do not carry him. 
 We may add, is it nothing to have the mind 
 awakened to the many proofs of design in the 
 hand to be brought to the conviction that every
 
 BY THE ORGANS OF SPEECH. 237 
 
 thing is orderly and systematic in its structure, 
 that the most perfect mechanism, the most 
 minute and curious apparatus, and sensibilities 
 the most delicate and appropriate, are all com- 
 bined in operation that we may move the hand ? 
 What the first impulse to motion is we do not 
 know, nor how the mind is related to the body ; 
 yet it is important to know with what extraordi- 
 nary contrivance and perfection of workmanship 
 the bodily apparatus is placed between that in- 
 ternal faculty which impels us to use it and the 
 exterior world. 
 
 I have been asked by men of the first educa- 
 tion and talents whether any thing really defi- 
 cient had been discovered in the organs of voice 
 in the orang-outang to prevent him from speak- 
 ing? The reader will give me leave to place 
 this matter correctly before him. In speaking, 
 there is first required a certain force of expired 
 air, or an action of the whole muscles of respira- 
 tion ; in the second place, the vocal chords, in 
 the top of the wind-pipe, must be drawn into 
 accordance by their muscles, else no vibration 
 will take place, and no sound issue ; thirdly, the 
 open passages of the throat must be expanded, 
 contracted, or extended by their numerous mus- 
 cles, in correspondence with the condition of the 
 vocal chords or glottis ; and these must all sym- 
 pathize before even a simple sound is produced. 
 But to articulate that sound, so that it may be-
 
 238 THE SUBJECT ILLUSTRATED 
 
 come a part of a conventional language, there 
 must be added an action of the pharynx, of the 
 palate, of the tongue and lips. The exquisite 
 organization for all this is not visible in the 
 organs of the voice, as they are called : it is to 
 be found in the nerves which combine all these 
 various parts in one simultaneous act. The 
 meshes of the spider's web, or the cordage of a 
 man-of-war, are few and simple compared with 
 the concealed filaments of nerves which move 
 these parts; and if but one be wanting, or its 
 tone or action disturbed in the slightest degree, 
 every body knows how a man will stand with 
 his mouth open, twisting his tongue and lips in 
 vain attempts to utter a word. 
 
 It will now appear that there must be distinct 
 lines of association suited to the organs of voice 
 different to combine them in the bark of a 
 dog, in the neighing of a horse, or in the shrill 
 whistle of the ape. That there are wide distinc- 
 tions in the structure of the different classes of 
 animals is most certain; but independently of 
 those which are apparent, there are secret and 
 minute varieties in the associating cords. The 
 ape, therefore, does not articulate First, be- 
 cause the organs are not perfect to this end. 
 Secondly, because the nerves do not associate 
 these organs in that variety of action which is 
 necessary to speech. And, lastly, were all the
 
 BY THE ORGANS OF SPEECH. 239 
 
 exterior apparatus perfect, there is no impulse 
 to that act of speaking. 
 
 Now I hope it appears, from this enumeration 
 of parts, that the main difference lies in the 
 internal faculty or propensity. As soon as a 
 child can distinguish and admire, then are its 
 features in action ; its voice begins to be modi- 
 fied into a variety of sounds; these are taken 
 up and repeated by the nurse, and already a 
 sort of convention is established between them. 
 The perfect correspondence is a contrivance ; 
 but the source of the articulation, that which 
 prompts to the first efforts, is in our intellectual 
 nature. We cannot, therefore, doubt that a 
 propensity is created in correspondence with the 
 outward organs, without which they would be 
 useless appendages. The aptness of the instru- 
 ment or external organ will undoubtedly im- 
 prove the faculty just as we find that giving 
 freedom to the expression of passion adds force 
 to the emotion in the mind.* 
 
 * One cannot but reflect here on that grand revolution which 
 took place when language, till then limited to its proper organ, 
 had its representation in the work of the hand. Now that a man 
 of mean estate can have a library of more intrinsic value than 
 that of Cicero, when the sentiments of past ages are as familiar 
 as those of the present, and the knowledge of different empires is 
 transmitted and common to all, we cannot expect to have our 
 sages followed, as of old, by their five thousand scholars. Na- 
 tions will not now record their acts by building pyramids, or by
 
 240 THE SUBJECT ILLUSTRATED. 
 
 On this, as upon many other occasions, there 
 may be an argument against the further multi- 
 plication of proofs in favour of natural religion. 
 It may be said that we vary the instances without 
 making the proofs stronger. Now certainly there 
 can be no higher argument in favour of the 
 perfection of design, than the simple fact, that 
 two intellectual beings can breathe out their 
 thoughts, and hold communion on the subject of 
 the ideas that arise in their minds. The know- 
 ledge of the means, and of the intricate organs by 
 which voice is produced, can indeed add nothing 
 to our wonder, or to the force of our Convic- 
 tion, that all that regards man's state is ordered 
 in perfection. So it may be a thing as admi- 
 rable, if philosophically considered, that we can 
 raise the arm by willing it, as when we know all 
 the relations of nerves arid muscles, and bones 
 and joints, through which it is accomplished. 
 But I would ask who thinks of this, or who 
 feels emotion, while he speaks or moves his 
 hand? Do these actions excite either admira- 
 tion or gratitude, and do we not require to be 
 brought to consider these operations anew? Is 
 
 consecrating temples and raising statues, once the only means of 
 perpetuating great deeds or extraordinary virtues. It is in vain 
 that our artists complain that patronage is withheld : for the 
 ingenuity of the hand has at length subdued the arts of design 
 printing has made all other records barbarous, and great men 
 build for themselves a " livelong monument."
 
 EXPRESSION IN THE HAND. 241 
 
 it not agreeable to know how the actions are 
 performed, and is it not important that the emo- 
 tions of surprise and gratitude thus excited 
 should be repeated and enforced, until they be- 
 come an enduring devotional feeling? In fine, 
 whilst it is pleasing to reflect that the great 
 authorities in natural science in times past have 
 entertained the belief of the great Architect, 
 and of the continuance of his government, it 
 cannot be without its use to add strength to the 
 same belief, from the improvements that are 
 daily making in all departments of knowledge. 
 
 We must not omit to speak of the hand as an 
 instrument of expression. Formal dissertations 
 have been written on this. But were we con- 
 strained to seek authorities, we might take the 
 great painters in evidence ; since by the position 
 of the hands, in conformity with the figure, they 
 have expressed every sentiment. Who, for 
 example, can deny the eloquence of the hands 
 in the Magdalens of Guido : their expression in 
 the cartoons of Raphael : or in the Last Supper, 
 by Leonardo da Vinci ? We see there expressed 
 all that Quintilian says the hand is capable of 
 expressing. " For other parts of the body, says 
 he, assist the speaker, but these, I may say, 
 speak themselves. By them we ask, we pro- 
 mise, we invoke, we dismiss, we threaten, we 
 intreat, we deprecate, we express fear, joy, grief,
 
 242 OPINION OF BUFFON. 
 
 our doubts, our assent, our penitence : we show 
 moderation, profusion, we mark number and 
 time. " Nam ceterae partes loquentem adju- 
 " vant, hre, prope est ut dicam, ipsoe loquuntur. 
 " His poscimus, pollicemur, vocamus, dimitti- 
 " mus, minamur, supplicamus, abominamur, 
 "timemus; gaudium, tristitiam, dubitationem, 
 " confessionem, penitentiam, modum, copiam, 
 " numerum, tempus, ostendimus, &c." 
 
 Buffon has attempted to convey to us the 
 mode in which knowledge may have been origi- 
 nally acquired, by watching (in fancy) the newly 
 awakened senses in the first created Man. But, 
 for that which is consistent and splendid in our 
 great poet who makes Man raise his wondering 
 eyes to Heaven and spring up by quick instinc- 
 tive motion as " thitherward endeavouring," 
 Buffon substitutes a bad combination of philo- 
 sophy with eloquence. 
 
 " To place the subject more distinctly before 
 us," says Buffon, " the first created man shall 
 speak for himself." The sentence which he is 
 made to utter is to the effect, " that he remem- 
 bers the moment of his creation that time, so 
 full of joy and trouble, when he first looked 
 round on the verdant lawns and crystal foun- 
 tains, and saw the vault of Heaven over his 
 head ;" and he proceeds to declare, " that he
 
 CHANGES IN THE GLOBE. 243 
 
 knew not what he was or whence he came, and 
 believed that all he saw was part of himself." 
 He is thus represented to be conscious of objects, 
 which even to see implies experience, and to 
 enjoy, supposes a thousand agreeable associa- 
 tions already formed : but from this blissful 
 state he is awakened by striking his head against 
 a palm tree, which he had not yet learned could 
 hurt him ! 
 
 Men are diffident of their first notions, and 
 conceive that philosophy must lead to something 
 very different from what they have been early 
 taught. Hence the absurdity of this combina- 
 tion of philosophy and poetry. 
 
 Later writers have argued that we have no 
 right to suppose that there has been, at any 
 time, an interruption to the uniform course of 
 nature. What they term the uniformity of 
 nature, is the prevalence of the same laws which 
 are now in operation. If, say they, it were 
 found that on the arrival of a colony in a new 
 country, fruits were produced spontaneously 
 around them, and flowers sprung up under 
 their feet, then, we might suppose that our first 
 parents were placed in a scene of profusion and 
 beauty suited to their helpless condition and 
 unlike what we see now in the course of nature. 
 It is not very wise to entertain the subject at 
 all ; but if it is to be argued, this is starting 
 altogether wide of the question. We do not
 
 244 CHANGES IN THE GLOBE 
 
 desire to know how a whole tribe migrating 
 westward could find sustenance, but in what 
 state man could be created to live without a 
 deviation from what is called the course of 
 nature. 
 
 If man had been formed helpless as an infant, 
 he must have perished. And if mature in body, 
 he must have been created with faculties suited 
 to his condition. A human being, pure from 
 the Maker's hands, with desires and passions 
 implanted in him, adapted to his state, and 
 with a suitable theatre of existence, implies 
 something very near what we have been early 
 taught to believe. 
 
 In every change which the globe has under- 
 gone, we see an established relation between the 
 animal created, and the elements around. It is 
 idle to suppose this a matter of chance. Either 
 the structure and functions of the animal must 
 have been formed to correspond with the con- 
 dition of the elements, or the elements must 
 have been controlled to minister to the neces- 
 sities of the animal ; and if the most careful 
 investigation lead us to this conclusion, in con- 
 templating all the inferior gradations of animal 
 existence, what is it that makes us so unwilling 
 to admit such an influence in the last grand 
 work of creation ? 
 
 We cannot resist those proofs of a beginning, 
 or of design prevailing every where, or of a First
 
 AND SUCCESSIVE EPOCHS. 245 
 
 Cause. When we are boM enough to extend 
 our enquiries into the great revolutions which 
 have taken place, whether in the condition of 
 the earth or in the structure of the animals 
 which have inhabited it, our notions of the 
 " uniformity" of the course of nature must suffer 
 some modification. Changes must, at certain 
 epochs, have been wrought, and new beings 
 brought into existence, different from the order 
 of things previously existing, or now existing. 
 Such interference is not contrary to the great 
 scheme of creation. It is not contrary to that 
 scheme, but only to our present state. For the 
 most wise and benevolent purposes, a convic- 
 tion is implanted in our nature that we should 
 rely on the course of events, as permanent and 
 necessary. We belong to a certain epoch ; and 
 it is when our ambitious thoughts carry us 
 beyond our natural condition, that we feel how 
 much our faculties are constrained, and our con- 
 ceptions, as well as our language, imperfect. 
 We must either abandon these speculations alto- 
 gether, or cease to argue purely from our present 
 situation. 
 
 It has been made manifest that man and the 
 animals inhabiting the earth have been created 
 with reference to the magnitude of the globe ; 
 that their living endowments bear a relation 
 to their state of existence and to the elements 
 around them. We have learnt that the system
 
 240 CHANGES IN THE GLOBE 
 
 of animal bodies is simple and universal, not- 
 withstanding the amazing diversity of forms 
 that meet the eye and that this system not 
 only embraces all living creatures, but that it 
 has been continued from periods of great anti- 
 quity, before the last revolution of the earth's 
 surface had been accomplished. The most 
 obvious appearances and the labours of the geo- 
 logist give us reason to believe that the earth 
 has not always been in the state in which 
 it is now presented to us. Every substance 
 which we see is compound ; we nowhere obtain 
 the elements of things : the most solid materials 
 of the globe are formed of decompounded and 
 reunited parts. Changes have been wrought on 
 the general surface, and the proofs of these 
 changes are as distinct as the furrows on a field 
 are indicative that the plough has passed over 
 it. The deeper parts of the crust of the 
 earth and the animal remains imbedded, also 
 give proofs that in the course of these revolu- 
 tions there have been long periods or epochs. 
 In short, progressive changes, from the lowest to 
 the highest state of existence, of organization 
 and of enjoyment, point to the great truth that 
 there was a beginning. 
 
 When the geologist sees a succession of stra- 
 tified rocks the lowest simple, or perhaps che- 
 mical; the strata above these, compound; and 
 others more conglomerated, or more distinctly
 
 AND SUCCESSIVE EPOCHS. 247 
 
 composed of the fragments of the former it is 
 not easy to contradict the hypothesis of an eter- 
 nal succession of causes. But there is nothing 
 like this in the animal body ; the material is the 
 same in all, the general design too is the same: 
 but each family, as it is created, is submitted to 
 such new and fundamental arrangements in its 
 construction as implies the presence of the hand 
 of the Creator. 
 
 There is nothing in the inspection of the spe- 
 cies of animals, which countenances the notion 
 of a return of the world to any former condition. 
 When we acknowledge that animals have been 
 created in succession and with an increasing 
 complexity of parts, we are not to be understood 
 as admitting that there is here proof of a grow- 
 ing maturity of power, or an increasing effort in 
 the Creator: and for this very plain reason, 
 which we have stated before, that the bestowing 
 of life or the union of the vital principle with 
 the material body, is the manifestation of a 
 power superior to that displayed in the formation 
 of an organ or the combination of many organs, 
 or construction of the most complex animal me- 
 chanism. It is not, therefore, a greater power 
 that we see in operation, but a power manifest- 
 ing itself in the perfect and successive adapta- 
 tion of one thing to another of vitality and 
 organization to inorganic matter. 
 
 In contemplating the chain of animal creation,
 
 248 COMPARISON OF SOME PARTS OF THE 
 
 we observe that even now there are parts of the 
 earth's surface which are marshy, and insalu- 
 brious ; and that these are the places inhabited 
 by amphibious and web-footed animals, such 
 as are suited to the oozy margins of swamps, 
 lakes, or estuaries. It is most interesting to 
 find that when the remains of animals, of similar 
 construction, are found in the solid rocks, the 
 geologist discovers, by other signs, that at the 
 period of the formation of these rocks, the sur- 
 face was flat, and that it produced such plants 
 as imply a similar state of the earth to these 
 swampy and unhealthy regions. 
 
 We thus mark changes in the earth's surface, 
 and observe, at the same time, corresponding 
 changes in the animal creation. We remark 
 varieties in the outward form, size, and general 
 condition of animals, and corresponding varieties 
 in the internal organization, until we find Man 
 created, of undoubted pre-eminence over all, and 
 placed suitably in a bounteous condition of the 
 earth. 
 
 Most certainly the original crust of the earth 
 has been fractured and burst up, that its con- 
 tents might be exposed ; that they might be 
 resolved and washed away, by the vicissitudes 
 of heat, cold, and rain : mountains and valleys 
 have been formed ; the changes of temperature 
 in the atmosphere have ensured continual motion
 
 EARTH WITH A FORMER CONDITION. 249 
 
 and healthful circulation : the plains have been 
 made salubrious, and the damps which hung on 
 the low grounds have gathered on the moun- 
 tains in clouds, so that refreshing showers have 
 brought down the soil to fertilize the plain. In 
 this manner have been supplied the means ne- 
 cessary for man's existence, and objects suited 
 to excite his ingenuity, and to reward it, and 
 fitted to develope all the various properties both 
 of his body and of his mind. And thus it is 
 " that the invisible things from the creation of 
 the world are perceived by what we do see." 
 
 There is extreme grandeur in the thought of 
 an anticipating or prospective intelligence : in 
 reflecting that what was finally accomplished in 
 man, was begun in times incalculably remote, 
 and antecedent to the great revolutions which 
 the earth's surface has undergone. Nor are 
 these conclusions too vast to be drawn from the 
 examination of a part so small as the bones of 
 the hand ; since we have shown that the same 
 system of parts which constitutes the perfection 
 of that instrument adapted to our condition, had 
 its type in the members of those vast animals 
 which inhabited the bays, and inland lakes of a 
 former world. If we seek to discover the rela- 
 tions of things, how sublime is the relation 
 established between that state of the earth's 
 surface, which has resulted from a long succes- 
 
 B. D D
 
 250 CONCLUDING REMARKS. 
 
 sion of revolutions, and the final condition of its 
 inhabitants as created in accordance with these 
 changes. 
 
 Nothing is more surprising to our measure of 
 time, than the slowness with which the designs 
 of Providence have been fulfilled. But as far 
 as we can penetrate by the light of natural 
 knowledge, the condition of the earth, and with 
 it of man's destinies, have hitherto been accom- 
 plished in great epochs. 
 
 We have been engaged in comparing the 
 structure, organs, and capacity of man and of 
 animals ; we have traced a relation ; but we 
 have also observed a broad line of separation 
 between them man alone capable of reason, 
 affection, gratitude, and religion : sensible to the 
 progress of time, conscious of the decay of his 
 strength and faculties, of the loss of friends, and 
 the approach of death. 
 
 One who was the idol of his day has recorded 
 his feelings on the loss of his son, in nearly these 
 words, " We are as well as those can be who 
 have nothing further to hope or fear in this 
 world. We go in and out, but without the sen- 
 timents that can create attachment to any spot. 
 We are in a state of quiet, but it is the tran- 
 quillity of the grave, in which all that could 
 make life interesting to us is laid." If in such 
 a state, there were no refuge for the mind, then 
 were there something wanting in the scheme of
 
 CONCLUDING REMARKS. 251 
 
 nature : an imperfection in man's condition at 
 variance with the benevolence which is mani- 
 fested in all other parts of animated nature. 
 
 tfi? ': ;* /:,*'! ',!* Jv ' /' -</U- ' 
 
 I have sometimes thought it possible, that a 
 greatly extended survey of nature may humble 
 too much our conceptions of ourselves ; and that 
 this requires to be corrected by the study of 
 things more minute, and in which we are more 
 directly concerned : by dwelling on the perfec- 
 tion of the frame of the animal body and the 
 marvellous endowments of the living properties. 
 When we have formed some estimate of the 
 immensity of the heavenly bodies, we are struck 
 with admiration in following the successive 
 advances made in the science : an improve- 
 ment in the curves of the glasses of the telescope, 
 a new mode of polishing the reflecting sur- 
 faces, a change in the chemical composition of 
 the glasses, or a more perfect adjustment of their 
 dispersive powers leads to the discovery of 
 circle beyond circle of worlds interminably. 
 We fan the imagination and labour to com- 
 prehend the immensity of the creation, and fall 
 back with the impression of the littleness of all 
 that belongs to us : our lives seem but a point of 
 time, compared with the astronomical and geolo- 
 gical periods, and we ourselves, as atoms, driven 
 about, amidst unceasing changes of the material 
 world.
 
 252 CONCLUDING REMARKS. 
 
 But it has been shown, that whether we take 
 the animal body as a single machine, or embrace 
 in the survey the successive creation of animals, 
 conforming always to the improving condition of 
 the earth, there is nothing like chance or irre- 
 gularity in the composition of the system. In 
 proportion indeed as we comprehend the prin- 
 ciples of mechanics, or of hydraulics, as appli- 
 cable to the animal machinery, we shall be 
 satisfied of the perfection of the design. If any- 
 thing appear disjointed or thrown in by chance, 
 let the student mark that for contemplation and 
 experiment, and most certainly, when it comes 
 to be understood, other parts will receive the 
 illumination, and the whole design stand more 
 fully disclosed. 
 
 The extension of knowledge has not neces- 
 sarily the effect of raising the mind to more con- 
 solatory contemplations. We may quote the 
 ancient philosopher in contrast with the modern. 
 The former, having nothing in his mind to draw 
 him from observing the just relations of human 
 beings to the world, but, on the contrary, seeing 
 every thing suited to man or subordinate, thinks 
 of him " as a little God harboured in a humane 
 body." But when by science, and the aid of 
 instruments, or " the ingenuity of the hand," 
 vision is extended to things too remote perhaps, 
 or too minute, to fall within our natural sphere ; 
 when instead of the extended plane, and visible
 
 CONCLUDING REMARKS. 253 
 
 horizon of the stable earth, our globe is thought 
 of as a ball rolling through space, amidst 
 myriads besides, greater than it : the expression 
 is excusable that " the earth with man upon it 
 does not seem much other than an ant-hill, 
 where some ants carry corn, and some carry 
 their young, and some go empty, and all to and 
 fro, a little heap of dust." 
 
 We may consider man, before the lights of 
 modern philosophy had their influence on his 
 thoughts, as in a state more natural ; in as much, 
 as he yielded unresistingly to those sentiments 
 which directly flow from the objects and phe- 
 nomena around him. But when that period 
 of society arrived, in which he made natural 
 phenomena the subjects of experiment or of phi- 
 losophical enquiry, then was there some danger 
 of a change of opinion, not always beneficial to 
 his state of mind. This danger does not touch 
 the philosopher so much as the scholar. He 
 who has strength of mind and ingenuity to make 
 investigations into nature, will not be satisfied 
 with the discovery of secondary causes his 
 mind will be enlarged, and the objects of 
 his thoughts and aspirations become more 
 elevated. But it is otherwise with those not 
 themselves habituated to investigation, and who 
 learn, at second hand, the result of those en- 
 quiries. If such a one sees the fire of heaven 
 brought down into a phial, and materials com-
 
 254 CONCLUDING REMARKS. 
 
 pounded, to produce an explosion louder than 
 the thunder, and ten times more destructive, the 
 storm will no longer speak an impressive lan- 
 guage to him. When in watching the booming 
 waves of a tempestuous sea along the coast, he 
 marks the line at which the utmost violence of 
 the ocean is stemmed, and by an unseen in- 
 fluence thrown back, he is more disposed to feel 
 the providence extended to man, than when the 
 theory of the moon's action is, as it were, inter- 
 posed between the scene which he contem- 
 plates, and the sentiments naturally arising in 
 his breast. Those influences on the mind which 
 are natural and just, and beneficently provided, 
 and have served to develope the sentiments of 
 millions before him, are dismissed as things 
 vulgar and to be despised. With all the pride 
 of newly acquired knowledge, his conceptions 
 embarrass, if they do not mislead him ; in short, 
 he has not had that intellectual discipline, 
 which should precede and accompany the acqui- 
 sition of knowledge. 
 
 But a man, possessed of genius of the highest 
 order, may lose the just estimate of himself, 
 from another cause. The sublime nature of his 
 studies may consign him to depressing thoughts. 
 He may forget the very attributes of his mind, 
 which have privileged these high contempla- 
 tions, and the ingenuity of the hand, which has 
 so extended the sphere of his observation.
 
 CONCLUDING REMARKS. 
 
 The remedy, to such a mind, is in the studies 
 which we are enforcing. The heavenly bodies, 
 in their motions through space, are held in their 
 orbits by the continuance of a power, not more 
 wonderful or more deserving of admiration, than 
 that by which a globule of blood is suspended 
 in the mass of fluids or by which, in due 
 season, it is attracted and resolved : than that, 
 by which a molecule entering into the composi- 
 tion of the body, is driven through a circle of 
 revolutions and made to undergo different states 
 of aggregation : becoming sometime, a part of a 
 fluid, sometime, an ingredient of a solid, and 
 finally cast out again, from the influence of the 
 living forces. 
 
 Our argument, in the early part of the vo- 
 lume, has shown man, by the power of the hand 
 (as the ready instrument of the mind) accommo- 
 dated to every condition through which his des- 
 tinies promise to be accomplished. We first see 
 the hand ministering to his necessities, and sus- 
 taining the life of the individual. In a second 
 stage of his progress, we see it adapted to the 
 wants of society, when man becomes a labourer 
 and an artificer. In a state still more advanced, 
 science is brought in aid of mechanical inge- 
 nuity, and the elements which seemed adverse 
 to the progress of society, become the means 
 conducing to it. The seas, which at first set
 
 250 CONCLUDING REMARKS. 
 
 limits to nations, and grouped mankind into 
 families, are now the means by which they are 
 associated. Philosophical chemistry has sub- 
 jected the elements to man's use ; and all tend 
 to the final accomplishment of the great objects 
 to which every thing, from the beginning, has 
 pointed the multiplication and distribution of 
 mankind, and the enlargement of the sources of 
 man's comfort and enjoyment the relief from 
 too incessant toil, and the consequent improve- 
 ment of the higher faculties of his nature. In- 
 stinct has directed animals, until they are spread 
 to the utmost verge of their destined places 
 of abode. Man too is borne onwards; and 
 although, on consulting his reason, much is dark 
 and doubtful, yet does his genius operate to 
 fulfil the same design, enlarging the sphere of 
 life and enjoyment. 
 
 Whilst we have before us the course of human 
 advancement, as in a map, we are recalled to 
 a nearer and more important consideration : for 
 what to us avail all these proofs of divine power 
 of harmony in nature of design the pre- 
 destined accommodation of the earth, and the 
 creation of man's frame and faculties, if we are 
 stopped here? If we perceive no more direct 
 relation between the individual and the Creator ? 
 But we are not so precluded from advancement. 
 On the contrary, reasons accumulate at every 
 step, for a higher estimate of the living soul, and
 
 CONCLUDING REMARKS. 257 
 
 give us assurance that its condition is the final 
 object and end of all this machinery, and of 
 these successive revolutions. 
 
 To this, must be referred the weakness of the 
 frame, and its liability to injury, the helpless- 
 ness of infancy, the infirmities of age, the pains, 
 diseases, distresses, and afflictions of life for by 
 such means is man to be disciplined his facul- 
 ties and virtues unfolded, and his affections 
 drawn to a spiritual Protector.
 
 ADDITIONAL ILLUSTRATIONS.
 
 ADDITIONAL ILLUSTRATIONS. 
 
 THE MECHANICAL PROPERTIES OF THE SOLID STRUC- 
 TURE OF THE ANIMAL BODY CONSIDERED. 
 
 IT has been shown in the first chapter that so- 
 lidity and gravity are qualities necessary to 
 every inhabitant of the earth ; the first to pro- 
 tect it ; the second, that the animal may stand, 
 and possess that resistance, which shall make 
 the muscles available for action. 
 
 The first material to be taken notice of, which 
 bestows this necessary firmness on the animal 
 textures, is the cellular substance. This consists 
 of delicate membranes, which form cells ; these 
 cells communicate with each other, and the 
 tissue thus composed enters every where into 
 the structure of the animal frame. It con- 
 stitutes the principal part of the medusa, which 
 floats like a bubble on the water; and it is 
 found in every texture of the human body. 
 It forms the most delicate coats of the eye ; 
 and gives toughness and firmness to the skin. 
 It is twisted into ligaments, and knits the 
 largest bones : it is the medium between bone, 
 muscle, and blood-vessel: it produces a certain
 
 262 ADDITIONAL ILLUSTRATIONS. 
 
 firmness and union of the various component 
 parts of the body while it admits of their easy 
 motion. Without it, we should be rigid, not- 
 withstanding the proper organs for motion ; and 
 the cavities could not be distended or contracted, 
 nor could the vessels pulsate. 
 
 But the cellular texture is not sufficient on all 
 occasions, either for giving strength or protec- 
 tion : nor does it serve to sustain the weight, 
 unless the animal lives suspended in water, or 
 creeps upon the ground. We see, therefore, the 
 necessity for some harder and more resisting 
 material being added, if the weight is to rest on 
 points or extremities ; or if the muscular activity 
 is to be concentrated. 
 
 Nature has other means of supplying the 
 fulcrum and lever, besides the bones, or true 
 skeleton, which we have been examining in the 
 first part of this volume : and perhaps we shall 
 find that there may be a system of solid parts 
 superior to what we have been studying in the 
 vertebrata. 
 
 The larvae of proper insects and the annelides 
 have no exterior members for walking or flying : 
 but to enable them to creep, they must have 
 points of resistance, or their muscles would be 
 useless. Their skins suffice ; and they are har- 
 dened by a deposit within them, for this purpose. 
 But if this skin were not further provided, it 
 would be rigid and unyielding, and be no sub-
 
 ADDITIONAL ILLUSTRATIONS. 263 
 
 stitute for bone. These hardened integuments 
 are, therefore, divided into rings ; to these the 
 muscles are attached ; and as the cellular mem- 
 brane between the rings is pliant, these anne- 
 lides can creep and turn in every direction. 
 
 Without further argument, we perceive how 
 the skin, by having a hard matter deposited 
 in it, is adapted to all the purposes of the 
 skeleton. It is worthy of notice that some 
 animals, still lower in the scale, the tubipores, 
 sertularia, cellularia, &c. exhibit something like 
 a skeleton. They are contained within a strong 
 case, from which they can extend themselves; 
 whilst the corals and madrepores, on the other 
 hand, have a central axis of hard material, the 
 soft animal substance being, in a manner, seated 
 upon it. But these substitutes for the skeleton 
 are, like shell, foreign to the living animal; 
 although in office they may resemble bone, in 
 sustaining the softer substance and giving form. 
 
 In the proper insect I should say that there is 
 a nearer approach to a skeleton, were it not 
 that the apparatus is more perfect than in some 
 of the animals which have a true skeleton. The 
 resisting material is here deposited externally : 
 and is converted to every purpose which we have 
 seen attained by means of the skeleton. Dis- 
 tinct members are formed, with the power of 
 walking, leaping, flying, holding, spinning, and 
 weaving. The hardened integuments, thus arti-
 
 2()4 ADDITIONAL ILLUSTRATIONS. 
 
 culated and performing the office of bones, have, 
 like them, spines and processes ; with this differ- 
 ence, that their aspect is towards the centre, in- 
 stead of projecting exteriorly. Were we to 
 compare the system of " resisting parts" in man 
 and in the insect, we should he forced to acknow- 
 ledge the mechanical provisions to be superior in 
 the lower animal ! The first advantage of the 
 skeleton (as we may be permitted to call the 
 system of hard parts in the insect) being exter- 
 nal and lifeless, is, that it is capable of having 
 greater hardness and strength bestowed upon it, 
 according to the necessities of the animal, than 
 can be bestowed upon bone ; true bone, being 
 internal and growing with the animal, is pene- 
 trated with blood vessels ; and therefore must be 
 porous and soft. The next advantage in the ex- 
 terior crust or skeleton is mechanical. The 
 hard material is strong to resist fracture, and to 
 bear the action of muscles, in proportion to its 
 distance from the centre : for the muscles in the 
 insect, instead of surrounding the bones, as in 
 the higher animals, are contained within the shell, 
 and the shell is, consequently, so much the fur- 
 ther thrown off from the axis of the limb. 
 
 When considering the larger vertebral ani- 
 mals, we had reason to say that there is a 
 correspondence between the resistance of the 
 bones and the power of the muscles; and we 
 may indulge the same reflection here. As the
 
 ADDITIONAL ILLUSTRATIONS. 265 
 
 integument covering the insect is much harder 
 than bone, so are the muscles stronger, compared 
 with the muscles of the vertebrata. From the 
 time of Socrates, comparisons have been made 
 between the strength of the horse and of the 
 insect ; to the obvious superiority of the latter. 
 
 As goodly a volume has been written on the 
 muscles of a caterpillar as has ever been dedi- 
 cated to the human myology. A very minute 
 anatomical description has been made of the 
 caterpillar which feeds upon the willow ; and 
 here we see that the annular construction of the 
 hard integument determines the plan of the 
 whole anatomy : the arrangement of the muscles, 
 and the distribution of the nerves. Each ring 
 has its three sets of muscles; direct, oblique, 
 traversing and interweaving, but yet distinct 
 and symmetrical ; and all as capable of being 
 minutely described as those of the human body 
 have been by Albinus.* Corresponding with 
 these muscles, the system of nerves is delicately 
 laid down. In short, we allow ourselves to be 
 misled in supposing that animals, either of 
 minute size or low in the scale of arrangement,- 
 exhibit any neglect or imperfection. Even if 
 they were more simple in structure, the admira- 
 tion should be the greater: since they have all 
 
 * The work referred to is by Lyonnet, who reckons four thou- 
 sand and sixty one muscles in this caterpillar. 
 B. E E
 
 ADDITIONAL ILLUSTRATIONS. 
 
 the functions in full operation which are neces- 
 sary to life. 
 
 We may perceive that a certain substance 
 calculated to sustain the more strictly living 
 part, and to give strength, may be traced through 
 all living bodies. In the vegetable it is the 
 woody fibre; and there, sometimes, as if to 
 mark the analogy, we may find silicious earth 
 deposited instead of the phosphate and car- 
 bonate of lime of the animal structure. In the 
 lower animals we find membranes capable of 
 secreting a solid material, and although in some 
 instances the substance is like leather or carti- 
 lage, it is in general earthy, and for the most 
 part, carbonate of lime. But when elasticity is 
 necessary, as well as general resistance, cartilage 
 is employed, which is a highly compressible and 
 elastic substance. Thus, fishes have a large 
 proportion of cartilage in their bones ; and from 
 this greater quantity, some have been called 
 cartilaginous in distinction to the osseous or true 
 fishes. The cartilaginous and elastic skeleton 
 comes into use in an unexpected manner in the 
 fish : when the salmon or trout leaps from the 
 water, the muscles bend the elastic spine ; this 
 recoils in aid of the muscles of the opposite 
 class : and thus these two forces combine to give 
 a powerful stroke with the tail on the water.
 
 267 
 
 MECHANICAL PROPERTIES OF BONE OR OF THE 
 TRUE SKELETON. 
 
 These considerations lead us the more readily 
 to understand the composition of bone. It is 
 combined of three parts having different proper- 
 ties, membrane, phosphate of lime, and carti- 
 lage. By these various substances being united 
 in its texture, it is enabled to resist stretching, 
 compression, and tortion. If bone had a super- 
 abundance of the earthy parts, it would break 
 like a piece of porcelain ; and if it did not pos- 
 sess toughness and some degree of elasticity, it 
 would not enable a man to pull and push and 
 twist. 
 
 Looking to the dense bone, we should hardly 
 suppose that it was elastic. But if ivory be pos- 
 sessed of elasticity, it cannot be denied to bone. 
 Now if a billiard ball be put upon a marble slab 
 which has been painted, a very small spot will 
 mark where the contact has been ; but if we let 
 the ball drop upon the marble from a height, we 
 shall find the spot much larger, and that the 
 elasticity of the ivory has permitted the ball to 
 yield and momentarily to assume an oblate 
 spheroidal form. 
 
 When a new principle is admitted into a com- 
 plex fabric, the utmost ingenuity can hardly
 
 ILLUSTRATIONS OF THK 
 
 anticipate all the results. Elasticity is exten- 
 sively employed in the machinery of the animal 
 body; and to show how finely it must be appor- 
 tioned, we shall take the illustration of a bridge 
 built with iron instead of stone, and having a 
 certain swing and elasticity. It lately happened 
 that a bridge of this kind fell, in very curious 
 circumstances, by the marching of a body of 
 soldiers over it. Now the bridge was calculated 
 to sustain a greater weight than this body of 
 men : and had they walked tumultuously over 
 it, it would have withstood the pressure. But 
 the soldiers marching to time, accumulated a 
 motion, aided by the elasticity of the material, 
 which broke it down. This leads us to form a 
 conception of the necessity of the fine adjustment 
 of the solid material in the animal fabric ; not 
 merely to enable it to sustain the incumbent 
 weight, or to resist transverse or oblique im- 
 pulses, but to withstand the frequent, and regu- 
 larly repeated forces to which it may be subject 
 in the various actions of the body. It gives 
 interest to this fact, that there is hardly a bone 
 which has not a constitution of its own, adjusted 
 to its place and use: the heel bone, the shin 
 bone, the vertebrae, and the bones of the head, 
 all differ in mechanical construction. 
 
 Let us compare the machinery of some com- 
 plicated engine with the mechanical properties 
 in an animal body, that we may comprehend
 
 MECHANICAL PROPERTIES OF BONE. *260 
 
 what is most truly admirable. Suppose the 
 engineer has contrived a steam carriage. He 
 has with the utmost possible precision calculated 
 the power of the steam, the pressure of the 
 atmosphere, the strength of the tubes and cy- 
 linder, the weight to be moved, and the friction 
 of the whole machinery. The engine is de- 
 signed, every thing is proportioned, and at length 
 it is constructed ; but it remains immoveable. 
 After much thought, the impediment is disco- 
 vered, the pressure is eased, or the friction is 
 diminished, and to the admiration of the be- 
 holders the carriage actually moves, till a pipe 
 bursts : but, this is mended, the whole is im- 
 proved, and a day is appointed for a great trial ; 
 the engine now runs for half a mile, and first, a 
 bolt is shaken loose, then a spring snaps ; but, 
 at length, with renewed ingenuity and labour 
 and much correction, after a few months, it 
 actually runs a stage. We have here, by com- 
 parison, a sort of proof how much there is to 
 admire in the mere machinery of an animal 
 frame, and before the powers of life are mea- 
 sured out to it : such for example as the force of 
 the heart to propel the blood, the resistance of 
 the tubes to the circulating fluids, the strength 
 of the limbs proportioned to the weight of the 
 body, the action of the muscles adapted to the 
 length of the bones, as levers, the flexibility of 
 the joints, the firmness of the bones to resist
 
 270 ILLUSTRATIONS OF THE 
 
 pressure or weight; their elasticity to prevent 
 concussion and fracture. In the animal body 
 there is no accident occurring from dispropor- 
 tioned forces, the active and resisting powers 
 are finely balanced* no second trial is wanted 
 to increase the power, or strengthen the levers, 
 or add to the elasticity of the springs it is at 
 once perfect ; perfect to its end. But to under- 
 stand this fully, and the adaptations in the 
 constitution of the bones, we must proceed a little 
 deeper in our investigation* 
 
 Perfect security against accidents in the ani- 
 mal body, and in man especially, is not con- 
 sistent with the scheme of nature. Without the 
 precautions and the continued calls to exertion, 
 which danger and the uncertainty of life pro- 
 duce, many of the faculties of the mind would 
 remain unexercised. Whence else would come 
 courage, resolution, and all the manly virtues? 
 Take away the influence of the uncertain dura- 
 tion of life, and we must suppose also a change 
 in the whole moral constitution of man. Whe- 
 ther we consider the bones as formed to protect 
 important organs, as in the skull : or to be levers 
 to which the muscles are attached, as in the 
 limbs : or in both capacities, as in the texture of 
 the chest : while they are perfectly adapted to 
 their function, they are yet subject to derange- 
 ments from accident. The mechanical adapta- 
 tions are perfectly sufficient to their ends ; and
 
 MECHANICAL PROPERTIES OF BONE. 271 
 
 afford safety in the natural exercises of the 
 body. To these exercises there is an intuitive 
 impulse, ordered with a relation to the frame of 
 the body ; whilst, on the other hand, we are 
 deterred from the excessive or dangerous use of 
 the limbs by the admonitions of pain. Without 
 such considerations, the reader would fall into 
 the mistake that weakness and liability to frac- 
 ture implied imperfection in the frame of the 
 body : whereas a deeper contemplation of the 
 subject will convince him of the incomparable 
 perfection both of the plan and of the execution. 
 The body is intended to be subject to derange- 
 ment and accident; and to become, in the 
 course of life, more and more fragile, until by 
 some failure in the frame-work or vital actions, 
 life terminates. 
 
 The bones of the extremities are called hollow 
 cylinders. Now, after having convinced our- 
 selves of the necessity of this formation, which 
 combines strength with lightness, we may find, 
 upon a more particular examination, that these 
 bones are extremely varied in their shapes : and 
 we are, at least, prone to believe that there is 
 much of chance or irregularity in their forms. 
 But such a conception is quite inconsistent with 
 a correct knowledge of the skeleton. As this 
 notion, however, is very commonly entertained 
 and leads to further mistakes, we shall take 
 pains to show, first, why the bones are hollow
 
 27*2 ILLUSTRATIONS OF THE 
 
 cylinders ; and, in the second place, why they 
 vary in their shape, so as to appear to the super- 
 ficial observer irregular. 
 
 The reasoning that applies to the hollow cylin- 
 drical bone serves equally to explain the admi- 
 rable structure of many other natural forms, as 
 that of a quill, a reed, or a straw. The last 
 example reminds us of the unfortunate man who 
 was drawn from his cell before the Inquisition, 
 and accused of having denied that there was a 
 God ; when, picking up a straw that had stuck 
 to his garments, he said, " If there were nothing 
 " else in nature to teach me the existence of a 
 " Deity, this straw would be sufficient." 
 
 It hardly requires demonstration to prove that, 
 with a given mass of material to make a pillar 
 or column, the hollow cylinder will be the form 
 of strength. The experiments of Du Hamei on 
 the strength of beams afford us the best illus- 
 tration how the material should be arranged 
 to resist transverse fracture. When a beam 
 rests on its extremities, bearing a weight upon 
 its centre, it admits of being divided into three 
 portions ; for these three parts are in a different 
 condition with regard to the weight. The lower 
 part resists fracture by its toughness : the upper 
 part, by its density and resistance to compres- 
 sion : but there is a portion between these which 
 is not acted upon at all ; which might be taken 
 away without any considerable weakening of the
 
 MECHANICAL PROPERTIES OF BONE. 273 
 
 beam : and which might be added to the upper 
 or the lower part with great advantage. It can 
 readily be understood how a tougher substance 
 added to the lower part would strengthen the 
 beam. We see it in the skin which islaid along 
 the back part of the Indian's bow ; or in the 
 leather of a carriage spring. The following is 
 a beautiful experiment to demonstrate what is 
 the quality in the timber which resists, at the 
 upper portion of the beam. If a portion, 
 amounting to nearly a third part, of the beam 
 be cut away, and a harder piece of wood be 
 nicely let into the space, the strength will be 
 increased ; because the hardness of this piece of 
 wood resists compression. This experiment I 
 like the better because it explains a very in- 
 teresting peculiarity in the different densities of 
 the several parts or sides of the bones. 
 
 In reading anatomical books, we are. led to 
 suppose that the various forms of the bones 
 result from the pressure of the muscles which 
 surround them. This is a mistake. Were we 
 to consider this as the true explanation, it would 
 not only be admitting an imperfection, but we 
 should expect to find, if the bones yielded in 
 any degree to the force of the muscles, that they 
 would yield more and more, and be ultimately 
 destroyed. There is nothing more admirable in 
 the living frame than the relation established 
 between the muscular power and the strength or
 
 274 ILLUSTRATIONS OF THE 
 
 capacity of passive resistance in the bones. The 
 deviations from the cylindrical forms are not 
 irregularities ; and if we take that bone which 
 deviates the furthest from the cylindrical shape, 
 the tibia, or shin bone, we shall have demonstra- 
 tion of the correspondence between the shape of 
 the bone and the force which it has to sustain. 
 
 If we consider the direction of the force in 
 walking, running, or leaping, and in all the 
 powerful exertions where the weight of the body 
 is thrown forwards on the ball of the great toe, 
 it must appear that the pressure against the shin 
 bone is chiefly on the anterior part : and there 
 is no doubt that if the tibia were a perfect cylin- 
 der, it would be subject to fracture even from 
 the mere force of the body itself being thrown 
 upon it. But if the column be stronger in pro- 
 portion as the material is distant from the centre, 
 we readily perceive how an anterior spine, or 
 ridge, should be thrown out : and if we attend 
 to the internal structure of that spine, we shall 
 find that it is much denser and stronger than 
 the rest of the bone. We cannot, here, deem 
 either the form or the density of this ridge, a 
 thing of accident; since it so perfectly corre- 
 sponds with the experiment of Du Hamel which 
 we have described, where the dense piece of 
 wood being let into the piece of timber, was 
 found to be a means of resisting transverse 
 fracture. If we proceed, with the knowledge
 
 MECHANICAL PROPERTIES OF BONE. 275 
 
 of these facts, to the examination of the different 
 bones of the skeleton, we shall find that every 
 where the form has a strict relation either to the 
 motion to be performed, or the strain to which 
 the bone is most exposed. 
 
 In comparing the true bones with the cover- 
 ings of the insects, we observed the necessity for 
 the porous structure of the former. If it be 
 necessary that the bone shall be very dense, it 
 will, in that case, no longer be possessed of the 
 power of re-union or re-production when it 
 breaks : it will not re-unite upon being frac- 
 tured, and if exposed, it will die. Here, then, is 
 an obvious imperfection. The bones of animals 
 cannot, in this manner, be made capable of sus- 
 taining great weight, without losing a property 
 which is necessary to their existence that of 
 restoration on their being injured. And even 
 were the material very much condensed, it does 
 not appear that the phosphate of lime, united as 
 it is with the animal matter, is capable of sustain- 
 ing any great weight. This accordingly limits the 
 size of animals. It may, perhaps, countenance 
 the belief that animals bear a relation in their 
 size and duration of life to the powers and life of 
 man that the larger animals have existed in a 
 former condition of the world. We allude only 
 to such animals as have extremities : for with 
 respect to the whale, its huge bulk lies out sup- 
 ported in the water. Some of the great fossil
 
 270 ILLUSTRATIONS OF THE 
 
 animals found in the secondary strata are esti- 
 mated to have been seventy feet in length, and 
 they had extremities. But the thigh and leg 
 did not exceed eight feet in length, while the 
 foot extended to six feet; a proportion, alto- 
 gether, which implies that the extremities as- 
 sisted the animal to crawl, rather than that they 
 were capable of bearing its weight, as the extre- 
 mities of the mammalia. However, we find that 
 in the larger terrestrial animals, the material of 
 the bones is dense, and that their cavities are 
 filled up ; the diameters of the bones of the ex- 
 tremities, with their spines and processes, being 
 remarkably large. Nothing can be conceived 
 more clumsy than the bones of the megatherium. 
 Hence it really appears that nature has ex- 
 hausted her resources with respect to this mate- 
 rial ; and that living and vascular bone could 
 not be moulded into a form to sustain the bulk 
 and weight of an animal much superior to the 
 elephant, mastodon, and megatherium.* 
 
 f * The subject may be illustrated in this manner : "A soft 
 " stone projecting from a wall, may make a stile strong enough 
 " to bear a person's weight ; but if it were necessary to double the 
 " length of the stile, the thickness must be more than doubled, 
 " or a freestone substituted ; and were it necessary to make this 
 " freestone project twice as far from the wall, it would not 
 " be strong enough to bear a proportioned increase of weight, 
 " even if it were doubled in thickness : granite must be placed 
 " in its stead ; and even the granite would not be capable of sus- 
 " taining four times the weight which the soft stone bore in the
 
 MECHANICAL PROPERTIES OF BONE. 277 
 
 With regard to the articulation of the bones, 
 we cannot mistake the reason of the surfaces 
 of contact being enlarged. Now the advantage 
 which is obtained from this expansion of the 
 ends of the bones, is gained without the motion 
 of the joint being impeded. In machinery it is 
 found that, if the pressure be the same, the ex- 
 tension of the surfaces in contact does not in- 
 crease the friction. If, for example, a stone or 
 a piece of timber, of the shape of a book or a 
 brick, be laid upon a flat surface, it may be 
 drawn across it with equal facility, whether 
 it rests upon its edge or upon its side. The 
 friction of the bones, which enter into the struc- 
 ture of the knee joint, is not increased by their 
 greater diameter : while obvious advantages are 
 gained by their additional breadth ; the liga- 
 ments which knit these bones give more strength 
 than they otherwise would, and the tendons 
 which run over them, being removed to a dis- 
 tance from the centre, have more power. 
 
 " first instance. In the same way the stones which form an arch, 
 *' of a large span, must be of the hardest granite, or their own 
 " weight will crush them. The same principle is applicable to 
 " the bones of animals. The material of bone is too soft to 
 " admit an indefinite increase of weight ; and it is another illus- 
 " tration of what was before stated, that there is a relation 
 " established through all nature : that the structure of the very 
 41 animals which move upon the surface of the earth is propor- 
 44 tioned to its magnitude, and the gravitation to its centre." 
 Animal Mechanics.
 
 278 
 
 OF THE MUSCULAR AND ELASTIC FORCES. 
 
 The muscular power is contrasted with the 
 elastic, as possessing a living property of mo- 
 tion. We acquiesce in the distinction, since 
 the muscular fibre ceases to have irritability or 
 power in death, while elasticity continues in 
 the dead part. But yet there is a property in 
 the elasticity of the living body which cannot 
 be retained after death. To illustrate this, we 
 shall take the instance of the elasticity in the 
 catgut string of a harp. Suppose that the string 
 is screwed tight, so as to vibrate in a given 
 time, and to sound the note correctly ; if that 
 string be struck rudely, it is put out of tune ; 
 that is, it is stretched and somewhat relaxed, 
 and no longer vibrates in time. This does not 
 take place in the living fibre ; for here there is 
 a property of restoration. If we see the tuner 
 screwing up the harp string, and with difficulty, 
 and after repeated attempts, bringing it to its 
 due tension, trying it with the tuning fork, 
 and with his utmost acquired skill restoring it to 
 its former elasticity, we have a demonstration of 
 how much life is performing in the fibres of the 
 animal frame, after every effort or exertion ; and 
 the more powerful the mechanical parts of the
 
 OF ELASTIC PARTS. 279 
 
 body are, the more carefully is the proper ten- 
 sion of the tendons, ligaments, and heart-cords 
 preserved. 
 
 Or we may take the example of a steel spring. 
 A piece of steel, heated to a white heat, and 
 plunged into cold water, acquires certain pro- 
 perties ; and if heated again to 500 of Fahren- 
 heit, it is very elastic ; possessing what is called 
 a " spring temper," so that it will recoil and 
 vibrate. But if this spring be bent in a degree 
 too much, it will lose part of its elasticity. 
 Should the parts of the living body, on the other 
 hand, be thus used, they have a power of resto- 
 ration which the steel has not. 
 
 If a piece of fine mechanism be made perfect 
 by the workman, it may be laid by and pre- 
 served : but it is very different with the animal 
 body. The mechanical properties of the living 
 frame, like the endowments of the mind, must 
 not lie idle, or they will suffer deterioration. If, 
 by some misfortune, a limb be put out of use, 
 not only is the power of the muscles rapidly 
 diminished, which every one will acknowledge, 
 but the property of resistance is destroyed ; and 
 bones, and tendons, and ligaments quickly 
 degenerate.* 
 
 * This subject is illustrated in the Essay on Animal Mechanics, 
 Part II.
 
 On the Position of the Head of Animals and its 
 Relation to the Spine : in Illustration of the 
 Statement made in the body of the Work, Unit 
 
 ALL PARTS OF THE SKELETON CORRESPOND WITH 
 EACH OTHER, AND THAT THE VARIATIONS IN 
 THEIR FORM DEPEND SOLELY ON THE FUNC- 
 TIONS. 
 
 IN the text, in speaking of the upper or anterior 
 extremity, it has been shown that the changes 
 which we see in the forms of different animals 
 are referable to one principle the adaptation 
 of the parts to their proper uses. We may, in 
 some measure, consider the head in animals as 
 performing the office of hands : and if we take 
 it in this view, we shall see how far it holds true 
 that the centre of the skeleton remains perma- 
 nent in its form, compared with the variations 
 in the extreme parts. It has been stated as the 
 opinion of some naturalists, that the varieties in 
 the conformation of the skeleton are to be ac- 
 counted for by a law which preserves the central 
 parts permanent, whilst the extremities are inci- 
 dent to change. I shall controvert that opinion, 
 and show that the spine and head, whilst they 
 retain their offices of protecting the brain and 
 spinal marrow, and are permanent in regard to
 
 OF THE HEADS OF ANIMALS. 281 
 
 them, vary in their processes or shapes, and in 
 their relations. Pursuing this idea, we shall be 
 able to account for the characteristic forms of 
 the larger quadrupeds. 
 
 The principle, then, which will guide us here, 
 as it will, indeed, in a more universal survey of 
 animal nature, is, that the organization varies 
 with the condition or the circumstances in which 
 the animals are placed that they may feed and 
 multiply. If we take into consideration any of 
 the great functions on which life depends, we 
 shall perceive that the apparatus, or the mode 
 of action of the parts is altered and adapted to 
 every changing circumstance. Digestion, for 
 example, is the same in all animals ; but there 
 is an interesting variety in the organization : 
 and the stomach will vary in its form and in the 
 number of its cavities, according to the food 
 received, in the quadruped, or bird, or fish, or 
 insect a variation not depending upon the size 
 or form of the animal, but adapted purely to the 
 conversion of its particular food into nourish- 
 ment. We shall find the gizzard in a fish or in 
 an insect, as perfect as in the fowl. So the 
 decarbonization of the blood is the same process 
 in all living animals : but the mode in which 
 the respiration is performed varies according to 
 circumstances ; and the apparatus is especially 
 modified and adjusted to the atmosphere or to 
 the water. 
 
 B. F F
 
 iJ82 VARIATIONS IN THE CENTRE 
 
 But although the organs subservient to the 
 grand functions, the heart and blood vessels, 
 the lungs, the stomach, be variously adapted to 
 the different classes of animals, they change 
 much less than the parts by which animals are 
 enabled to pursue their prey or obtain their food. 
 Their extremities, by which they walk, or run, 
 or creep, or cling, must vary infinitely. And so 
 their teeth and horns and the position of their 
 head and the strength of their neck exhibit 
 nearly as much variety as their proper extremi- 
 ties ; because they likewise must be adapted to 
 their different modes of obtaining food, or of com- 
 bating their enemies. Let us then, in pursuing 
 this principle, observe the meaning of the forms 
 of the more remarkably shaped animals. 
 
 When we look upon the boar's head,* we 
 
 * This is a sketch of the dried head of the Sus Ethiopicus
 
 AND IN THE EXTREMITIES. 283 
 
 comprehend something of his habits; and see 
 what must be the direction of his strength. He 
 feeds by digging up roots, and the instruments 
 by which he does this, are also those of his 
 defence. The position of the tusk defends the 
 eye in rushing through the underwood ; and the 
 formation of the skull and of the spine and the 
 mass of muscle in the neck, all show the inten- 
 tion that he shall drive onward with his whole 
 weight and strength, so that he may rend with 
 his tusks. Accordingly, we see that the back 
 part of the skull rises in remarkable spines or 
 ridges for the attachment of muscles, and that 
 corresponding with these, the spinous processes 
 of the vertebra of the neck and back are of 
 extraordinary length and strength. These pro- 
 cesses distinctly indicate the power of the 
 muscles which pass from the neck to the head. 
 We now understand the reason of the shortness 
 and inflexibility of the neck : because the power 
 of the shoulders is directed to the head, and, we 
 
 with part of the skull exposed. The tusks show what a 
 formidable animal it has been. That which rises out of the 
 upper jaw is of great size, and we must admire the manner in 
 which the tusk of the lower jaw closes upon that of the upper 
 one so as to strengthen it near its root. The great size and 
 sharpness of these tusks illustrate what is offered in the text 
 that the main strength of the animal must be directed towards 
 them. The rising of the back of the head will be seen to cor- 
 respond with the great height and strength of the spinous pro- 
 cesses of the back exhibited in the next figure, of the wild boar 
 of Germany.
 
 284 
 
 VARIATIONS IN THE CENTRE 
 
 may say, to these large tusks. An elongated 
 and flexible neck would have rendered these 
 provisions useless. The characteristic form of 
 the wild boar, then, consists in the height of the 
 back, the shortness and thickness of the neck, 
 the wedge shape of the head, the projection of 
 the tusk, and the shortness of the fore legs, which 
 must always be in proportion to the neck. 
 
 Thus we perceive that the skull, unaffected in 
 its office for containing and protecting the brain, 
 is yet subject to variations in its form and place 
 in reference to its other functions; because it 
 must be adapted, just as the extremities are, to 
 the animal's mode of life. In the same manner, 
 we see that the spine is permanent in its office as 
 a tube to protect the spinal marrow, but that it
 
 AND IN THE EXTREMITIES. 
 
 285 
 
 varies in its processes and articulations as they 
 bear a reference to the skull : and that although 
 this be the very central part of all, it varies in 
 due degree, and is accommodated to the whole 
 skeleton . 
 
 What a complete contrast, then, there is 
 between this animal and any of the feline tribe 
 a contrast of form and motion at once referrible 
 to their spine. In the tiger or leopard, we see 
 the perfect flexibility of the body, and a motion 
 of the spine, almost vermicular, corresponding 
 with the teeth and jaws and the free motion of 
 the paws. 
 
 The peculiarity of form in the elephant has
 
 2:\(i VAUIATIONS IN THE CENTRE 
 
 been happily illustrated by the celebrated Cu- 
 vier: and the principle may be pursued in ;i 
 manner interesting both to the Naturalist and 
 Geologist. 
 
 We may feel in ourselves a projection of the 
 spine between the shoulders which marks the 
 process of the " vertebra prominens" When we 
 stoop forward, as in reading a book which lies 
 upon the table, we may feel a ligament extending 
 from this process to the back of the head. It 
 suspends the head and relieves the muscles. 
 But as, for the most part, man carries his head 
 balanced upon the extremity of the spine, or can 
 vary its relation under fatigue, that suspensory 
 ligament is not to be compared in strength with 
 the corresponding part in quadrupeds ; where 
 from the horizontal position of the spine, the 
 head always hangs : and there would be a great 
 waste of muscular exertion were there not the 
 interposition of this elastic ligament, and were 
 it not of proportionate power.* It is long and 
 strong in the horse ; and the admirable thing is 
 the accurate adjustment of the elasticity of this 
 ligament to the weight and position of the head. 
 The head is balanced by it as on a steel-yard. 
 With this circumstance in our mind, let us ob- 
 serve the peculiar form of the elephant. 
 
 1. We begin, again, as in treating of the boar, 
 
 * See " On the Muscular and Elastic Forces," p. 278.
 
 AND IN THE EXTREMITIES. 287 
 
 by observing the teeth. We find that one of 
 the grinders of the elephant weighs seventeen 
 pounds ;* and of these there are four in the 
 skull, besides the rudiments of others. 2. We 
 next observe how admirably these grinding 
 teeth are suited to sustain great pressure and 
 attrition. 3. The jaws must be provided to 
 give deep socketing to such teeth : and they 
 must have space and strength to give lodgement 
 and attachment to muscles sufficient for moving 
 this grinding machine. 4. The animal must 
 have its defence too. Now each of the tusks 
 sometimes weighs as much as one hundred and 
 thirteen pounds : and being projected, they may 
 be considered as if placed at the end of a lever. 
 5. If this enormous and heavy head had hung 
 on the end of a neck having anything like the 
 proportion, in its length, which we see, for ex- 
 ample, in the horse, it would have inordinately 
 increased the pressure on the anterior extre- 
 mities ; and more than four times the expen- 
 diture of muscular power would have been ne- 
 cessary to the motion of the head. 6. What 
 has been the resource of nature? There are 
 seven vertebrae of the neck in this animal, the 
 same number that we find in the giraffe ; but 
 they are compressed in a very remarkable 
 manner, so as to bring the head close upon the 
 
 * The natural tooth weighed seventeen pounds, the fossil 
 tooth sixteen and a-half pounds.
 
 288 
 
 VARIATIONS IN THE CENTRE 
 
 body : and thus the head is, as it were, a part 
 of the body, without the interposition of the 
 
 neck. 7.' But the animal must feed : and as its 
 head cannot reach- the ground, it must possess 
 an instrument like a hand in the proboscis, to 
 minister to the mouth, to grasp the herbage and 
 lift it to its lips. Thus we perceive that the 
 form of the elephant, as far as regards the pecu- 
 liar character in the shoulders and head, the 
 closeness of the head to the body, the possession 
 of the proboscis, and the defence of that pro- 
 boscis by the projecting tusks, is a necessary 
 consequence of the weight of the head, and, 
 indeed, of the great size of the animal. 
 
 We may carry the inquiry a little further to
 
 AND IN THE EXTREMITIES. 289 
 
 the effect of elucidating a very curious part of 
 natural history. The mastodon is the name of 
 an extinct animal, which must have been nearly 
 of the same size as the elephant. It has re- 
 ceived that name from the early familiarity of 
 Naturalists with the teeth ; which have upon 
 their surfaces of contact mammillary-shaped 
 projections: and it was supposed, at one time, 
 that they might have belonged to a carnivorous 
 animal. But on a portion of the upper jaw 
 being found with the teeth, it admitted of this 
 course of reasoning. 1 . In the upper maxillary 
 bone of all vertebrated animals, there is a hole 
 which transmits a branch of the fifth pair of 
 nerves (see p. 149). This nerve goes to the 
 upper lip. But when, as in the elephant, there 
 is the addition of a great proboscis, since that 
 organ possesses sensibility through this nerve, 
 the nerve will be proportion ably large, and the 
 hole, consequently, through which it is trans- 
 mitted. Hence it follows that when we possess 
 a portion of the bones of the face, with the at- 
 tached tooth of the mastodon, we can infer, by 
 the greater size of this hole or foramen, that the 
 nerve supplied more than the lips that the 
 animal had a proboscis, and was a species of 
 elephant. 
 
 It has been more lately discovered by our 
 conservator in the College of Surgeons, Mr. Clift, 
 that judging by the teeth, and including in the 
 
 B. G G
 
 2UO VARIATIONS IN THE CENTRE 
 
 survey the extinct as well as the living animals, 
 there was a regular series, from the Asiatic ele- 
 phant to the mastodon of the Ohio. If we con- 
 sider that tooth to be the most perfect, which is 
 most capable of resisting attrition, either from 
 the mode of its growth or its structure, we shall 
 begin with the great Asiatic elephant. The 
 grinding tooth of this animal consists of alter- 
 nate layers of the ivory and enamel, and, from 
 the closeness with which these parts are laid 
 together, of a third portion, called crusta petrosa. 
 The tooth of the African elephant is easily dis- 
 tinguished, by the wide interstices between the 
 layers of enamel. On the banks of the Irawadi, 
 the tooth of a new species of mastodon is found, 
 where the mammillary processes are so high, 
 and the interstices are so deep that if a section 
 be made of it, it resembles the tooth of the 
 African elephant, and stands intermediate be- 
 tween that and the mastodon giganteum of North 
 America. 
 
 Let us consider this principle in another light, 
 and see how the neck and head are accommo- 
 dated for feeding, when there is no trunk or 
 proboscis, and when the animal has a short 
 neck. The elk is a strange, uncouth animal, 
 from the setting on of its head. The weight of 
 the horns is enormous : and if the head and 
 horns w r ere extended forwards from the body of 
 the animal on an elongated neck, it would be
 
 AND IN THE EXTREMITIES. 
 
 291 
 
 preposterous and, in fact, they would over- 
 balance the body. Therefore it is, we must 
 
 presume, that the head is so curiously approxi- 
 mated to the trunk. When we observe, in the 
 next place, the want of relation between the 
 length of the fore legs and that of the neck, it 
 becomes an interesting circumstance to find 
 that the animal feeds off the sides of the rocks, 
 and does not browse upon the herbage at its 
 feet. A very remarkable proof of the incapacity 
 of this animal to feed in the common way was 
 afforded by an accident which befell a fine male 
 specimen confined in the Zoological Gardens. 
 To reach the ground on which his food was
 
 292 VARIATIONS IN THE CENTRE 
 
 unintentionally scattered, he had to extend out 
 his fore legs laterally ; in this position his foot 
 slipped, he dislocated his shoulder, and died of 
 the accident. 
 
 Contrasted with the elk in a most remarkable 
 manner, we have the giraffe ; which feeds upon 
 the branches of lofty trees. The whole con- 
 stitution and form of this animal is provided to 
 enable it to reach high the fore legs are long, 
 the neck still longer, the head is remarkably 
 small and light, and the tongue has a power 
 of elongation which no other quadruped pos- 
 sesses. The tongue is, indeed, not inaptly com- 
 pared with the trunk of the elephant; he can 
 extend it seventeen inches, and he twists it 
 about, so that it resembles a long black worm ; 
 and it is used with extraordinary dexterity in 
 picking up a straw as well as pulling down a 
 branch. The anatomy of the bones of the giraffe 
 is full of interest too, as showing the accommo- 
 dation in the structure to the necessities of the 
 animal's condition. And, first, of the head : if 
 we have the skulls of the giraffe and of the 
 camel or horse before us, we are struck with the 
 delicacy of the former : it is cellular, and thin 
 and light as a paper case. Can there be any 
 thing more obvious than that this is provided in 
 consequence of the extraordinary length of the 
 neck, or on the consideration (if we may use the 
 expression) that, if the skull of the giraffe had
 
 AND IN THE EXTREMITIES. 293 
 
 been as strong and heavy as that of the horse or 
 camel, it would have preponderated too much at 
 the extremity of such a neck. 
 
 There is an accommodation also in the posi- 
 tion of the spine. In most quadrupeds the 
 spine lies horizontally. If it had been so placed 
 in the giraffe, the whole weight of the shoulders, 
 neck, and head would have been thrown on 
 the anterior extremities. But from the shortness 
 of the hind legs, and the oblique position of the 
 trunk, the hind legs bear a portion of the weight 
 of the neck and head, parts which, in other crea- 
 tures, are sustained altogether by the fore legs.* 
 When we look to the ribs, we see another pecu- 
 liarity that may be accounted for on the same 
 consideration of the length and consequent weight 
 of the neck and head. The chest or thorax 
 rests, of course, upon the anterior extremities: 
 and we shall find that those ribs which bear 
 the pressure are of great comparative strength, 
 while the ribs posterior to these are singularly 
 contrasted with them, by their delicacy and 
 weakness, and by their mobility in breathing. 
 In short, it appears that the fore part of the 
 chest, which, in a manner, intervenes between 
 the neck and the anterior extremities, requires 
 its compages to be particularly firm and strong, 
 
 * The ligamentum nuchee in this animal extends the whole 
 length of the spine, from the os sacrum to the skull.
 
 294 VARIATIONS IN THE CENTRE 
 
 and that the motions of respiration belong more 
 to the posterior ribs.* Although in this creature 
 
 there seems to be a due proportion between the 
 
 * We have here a sketch of the skeletons of the hippopotamus 
 and of the camel, as they stood accidentally contrasted. The 
 head of the hippopotamus is of great strength and weight, and it 
 is appended to a short neck ; in the shortness of the legs also 
 we see the correspondence that we have had occasion to remark 
 between the position of the head and the height of the trunk from 
 the ground. The camel is, in every respect, a contrast. It must
 
 AND IN THE EXTREMITIES. 295 
 
 legs and the neck, yet he is not suited to browse 
 the grass, but to feed on the high branches of 
 trees. In the attempt to reach the ground with 
 his mouth the limbs appear to be in danger of 
 suffering dislocation. He extends his feet late- 
 rally, elevates the scapulae, draws in the crupper, 
 and stretches the neck, so as to present a very 
 ludicrous figure. 
 
 OF THE HORSE'S HEAD. It is perhaps better 
 to draw our argument from something familiar 
 and constantly before us : let us, then, take it 
 from the form of the horse. It has been affirmed 
 that the sound of neighing in the horse results 
 from two cavities in the head, called the Eusta- 
 chian cavities, because they communicate with 
 the tubes of that name which lead from the ear 
 to the throat : but this is a very unsatisfactory 
 account of these cavities. We are of opinion 
 that they are connected with this subject, the 
 weight of the head, the power of mastication, 
 and the length of the neck. It is a very re- 
 markable circumstance that a horse, whose 
 " points" are approved of by the jockeys, will 
 
 have rapidity and ease of motion ; that is secured by the length 
 of the extremities ; and according with the extremities, are the 
 length of the neck and the lightness of the head. Here is a 
 skeleton, then, of an animal which is properly terrestrial, accom- 
 modated to all the other peculiarities of its organization, and 
 adapted for a rapid and long continued course: the hippopotamus, 
 on the other hand, seeks its safety in the water, and its un- 
 couth form and weight are suited to that element.
 
 "296 VARIATIONS IN THE CENTRE 
 
 starve in a grass field ; for by breeding and 
 crossing they contrive, in a manner one would 
 almost say artificially, to combine the inci- 
 dental defects of nature, so as to make the pro- 
 portions of the animal correspond with their 
 ideas of perfection ; for they have got a notion 
 that a short neck and a small head are excel- 
 lencies, as diminishing the weight upon the fore 
 feet. They observe that the splints, corns, sand- 
 cracks, whitters, inflammations, and other dis- 
 eases of the horse's foot, are almost exclusively 
 found in the anterior extremity, and they at- 
 tribute these to the weight of the head and neck 
 in conjunction with the artificial condition of the 
 horse. Were it the shoeing and the hard roads, 
 the effect would be equally perceptible on the 
 hind feet. Such considerations tend to show 
 the importance of the peculiarity now to be 
 pointed out in the horse's skull. 
 
 On looking to the horse's head in profile, we 
 see that its peculiar form, and especially the 
 great depth of jaws, posteriorly, is a necessary 
 consequence of the length of the grinding teeth. 
 We have already noticed the magnitude and 
 weight of the elephant's head, corresponding 
 with the enormous teeth, formed for attrition. 
 If we apply the same rule to the head of the 
 horse, we shall see how curiously it accounts for 
 the peculiar shape of its skull. Like the ele- 
 phant, it is graminivorous ; and the structure of
 
 AND IN THE EXTREMITIES. 297 
 
 the teeth evinces how well they are calculated to 
 masticate without wasting. To enable them to 
 bear great pressure they are socketted deeply in 
 the jaw ; and as the strength of the muscles 
 is not provided merely for closing the jaws, as in 
 the carnivorous animals, but for grinding or 
 drawing the jaw laterally, there is extraordinary 
 space given for the lodgement of the muscle 
 called masseter, which has the double action of 
 closing the teeth and of drawing the lower jaw 
 across the upper, as in mastication. Here then, 
 we have the reason for that large square portion 
 of the jaw under the ear, which peculiarly dis- 
 tinguishes the horse's head. 
 
 The maxillary and nasal cavities are very 
 large, but the space which they occupy does not 
 suffice to correspond with the remarkable depth 
 of the lower jaw. In fact, the larynx and pha- 
 rynx, the contained parts, cannot fill up the 
 whole depth of the head here, so that above these 
 tubes there is a great space, neither required for 
 the lodgement of the brain, nor for the bony 
 cavities of the nose, nor for the pharynx, nor the 
 trachea, but solely resulting from the great size 
 of the jaws. Had this been occupied by solid 
 bone, it would have added materially to the 
 weight of the head ; the space, therefore, betwixt 
 the upper part of the spine, the jaw, and the 
 base of the skull, is filled up by two great mem- 
 branous cells, which have a communication with
 
 298 VARIATIONS IN THE CENTRE 
 
 the cavities of the nose. On the whole, then, we 
 may consider these great cells in the horse's 
 head as permitting the enlargement of the jaw 
 bone at its back part, so as to afford a deep socket- 
 ting for the grinding teeth, and to give a sufficient 
 lodgement for the powerful muscles employed in 
 mastication, without very considerably increasing 
 the solid material of the head. Advantage is 
 here taken of the admission of air to increase 
 the volume and strength of the parts, as in birds, 
 without adding to the weight. 
 
 We have said that jockeys observe the effect 
 of a large and heavy head in a horse ; we now 
 perceive that if the horse's skull had been formed 
 without this provision, the head must have greatly 
 exceeded in weight, and in the running horse 
 especially, this would have been a positive de- 
 fect; for in running, the horse would not have 
 l>een properly balanced upon its extremities, 
 and the weight upon the fore-feet would have 
 been so much increased as to have rendered 
 him still more liable to those diseases of the 
 foot which artificial condition subjects it to. 
 
 This provision, by which the head of the horse 
 is made lighter, has a parallel in the head of the 
 spermaceti whale. The spermaceti whale is a 
 species of the physeter or cachelot whale, which 
 has a very large head, and is remarkable for 
 having teeth ; the common whale having only 
 whale bone in its mouth. It is probable that 
 the length of the head thus loaded as it is, throws
 
 AND IN THE EXTREMITIES. 299 
 
 the lungs too far behind the centre of gravity, to 
 permit the head to be buoyant; therefore, the 
 large cavities about the head, (twelve feet long, 
 and four feet deep) are filled with a material 
 lighter than the water, and thus the equilibrium 
 is maintained. 
 
 Although the changes in the shape of the 
 skulls of animals are principally forwards, yet 
 the slighter deviations in the back part may in- 
 dicate much, if minutely scanned. For example, 
 a portion of a skull was found, among other inte- 
 resting specimens of fossil bones, in the caves 
 of the limestone rocks, near Plymouth. It con- 
 sisted merely of the condyles or articulating pro- 
 cesses of the skull which join it to the vertebra 
 of the neck, and a portion of the occipital and 
 temporal bones. Yet from these it could be 
 ascertained that the fragment belonged to an 
 hyaena : although its proportions were double 
 those of the corresponding parts of the largest of 
 the recent species. First, the high spine showed 
 the strength of the neck ; secondly, the depth 
 and extent of the fossa or hollow for the lodge- 
 ment of the temporal muscle proved that there 
 was a remarkable mass, and consequent strength 
 of muscle for closing the jaws ; thirdly, it 
 belonged neither to the bear nor to the tiger, 
 which was shown by the extraordinary thickness 
 and density of the whole bone. In this last 
 respect, the portion of bone corresponded with
 
 300 VARIATIONS IN THE CENTRE 
 
 no animal but the hyaena ; for the skull of the 
 hyaena participates in the strength which is so 
 remarkable in its teeth ; these being capable of 
 breaking the strongest bones.* 
 
 On this subject, Dr. Buckland has given an 
 example of deduction, founded on the structure 
 of the teeth of the hyaena, not inferior to the 
 best specimen of Cuvier's reasoning on the 
 fossil bones. In lecturing on the comparative 
 anatomy of the skeleton, I put the subject in 
 this light : " We have seen that all nature is 
 full of life ; and where food is to be obtained, 
 there are animals in structure suited to reach it. 
 Suppose that the horse is run down by the wolf, 
 and fed upon by the lesser carnivorous animals 
 and birds of prey: in these large cylindrical 
 bones which are left, there is abundance of 
 nutriment, and yet these animals cannot get 
 at it. Turn your attention, then, to the skull 
 of the hyaena. It has a clumsiness and weight, 
 in contrast with that of the dog, or the wolf, 
 or the bear : and observing the teeth, you see 
 them conical which is the very form of strength, 
 and they are, indeed, as if case-hardened, com- 
 pared with those of other animals. Proportioned 
 to the power of resistance of the teeth are the 
 
 * This specimen is in the Museum of the College of Surgeons, 
 and is beautifully drawn in Mr. Clift's paper in the Philosophical 
 Transactions.
 
 AND IN THE EXTREMITIES. 301 
 
 size and density of the jaws. This hollow for 
 the lodgement of the temporal muscle, which 
 closes the jaws, and this prominence of the 
 zygomatic arch, which gives attachment to an- 
 other muscle of the same class, produce the 
 extraordinary breadth of face of this very ugly 
 animal ; and corresponding with the strength of 
 its teeth, jaws, and muscles, you see that the 
 whole skull is thicker and denser in its texture, 
 as if to show, by the supporting frame-work, the 
 strength of the engine ; an engine capable of 
 breaking these powerful cylindrical bones of 
 larger animals, and of disclosing a rich repast in 
 the marrow." 
 
 In the earlier part of the volume, we have 
 noticed the most remarkable peculiarities of the 
 skeletons of birds ; and we may take this op- 
 portunity of observing the relation between the 
 form of the bird and some of the principal 
 functions. Putting digestion and respiration for 
 the present, out of the question, the continuation 
 of the species is the next in importance. Now 
 a bird, to be buoyant and capable of flying, 
 could not have been viviparous. If we have 
 seen that a full stomach impeded the flight of a 
 carnivorous bird, it is evident that it could not 
 have carried its young within it. Is it not cu- 
 riously provided, then, that the bird shall pro- 
 duce its offspring by a succession of small eggs, 
 which shall accumulate in the nest, instead of
 
 302 VARIATIONS IN THE CENTRE 
 
 growing in the body ? In short, it requires no 
 argument to prove that the hollow bones of the 
 skeleton, the extension of the breast-bone, the 
 air-cells, the quill-feathers, the bill, and the 
 laying of eggs, are all in necessary relation to 
 each other. 
 
 Since we have spoken of the relation of the 
 form of the skeleton to the continuation of the 
 species, in the bird, we may for the same object 
 revert to the quadrupeds. In all the mammalia, 
 there is nothing more extraordinary than the 
 deviation in the skeleton of the kangaroo from 
 the general form. Joined to this, there is a 
 remarkable peculiarity in the manner in which 
 this animal produces its young. Instead of re- 
 maining within the mother for the usual period 
 of gestation, the young, by some peculiar mode 
 not perfectly understood, are excluded from 
 within the belly, and are found attached to the 
 teats ; where they hang by the mouth, covered 
 by an exterior pouch, formed of the skin, until 
 from minute and shapeless things, they are ma- 
 tured to the degree in which the young of other 
 animals are usually brought forth. 
 
 Now we think that the upright position of this 
 animal (for it is the only creature except man 
 which rests in the perpendicular), and the dis- 
 proportioned magnitude of the lower part of its 
 body, are the reasons of the peculiarity in its 
 mode of gestation. Without entering far into
 
 AND IN THE EXTREMITIES. 303 
 
 this subject, we may observe that there must be 
 an accurate correspondence between the form of 
 the young offspring and the bones of the mother 
 through which it must be expelled. The head 
 and anterior part of the young animal must be 
 large : but in the kangaroo, the anterior part 
 bears no proportion to the magnitude of the parts 
 behind. Again, the bones called pelvis are ne- 
 cessarily formed to sustain the viscera, if the 
 animal be provided for the perpendicular po- 
 sition ; and this is the case with the kangaroo. 
 Nature has, therefore, accomplished the produc- 
 tion of the young safely and by the simplest 
 means, that of anticipating the period of the 
 separation of the young animal, and providing 
 for its growth exteriorly, after it has passed 
 through the circle of bones called the pelvis. 
 For these reasons we conclude that there is a 
 relation between the mode of producing the 
 offspring and the form of the skeleton. 
 
 I hope that I have gone far enough to prove 
 that where there is uniformity in the shape of 
 any part of the skeleton, it depends on the per- 
 manence of the function of the organ to which 
 it stands related. The head and spine are, in 
 certain respects, permanent in their forms ; 
 because the brain and spinal marrow vary only 
 in size : but as far as regards their application 
 as instruments for obtaining food, for attack, or 
 defence, they are very curiously changed in
 
 304 IMAGINARY ANIMALS. 
 
 their processes and articulations, and suited to 
 the varying uses of the parts; and we may 
 observe that there is no change in any part of 
 the body whether in the spine, or the occiput, 
 or the jaws, or the teeth, or the pelvis, or the ex- 
 tremities without a corresponding adaptation 
 extending through the whole skeleton. 
 
 IMAGINARY ANIMALS. 
 
 ARCHDEACON PALEY has said, " no doubt we can 
 imagine a greater variety of animals than do 
 actually exist." But what is the fact? If we 
 look to the fabled animals of antiquity, not one 
 of them could have existed ; and it may serve to 
 show the imperfection of man's ingenuity com- 
 pared with nature, and at the same time demon- 
 strate the perfection of the system of the animal 
 body, if for a moment, we survey these imagi- 
 nary animals and enquire whether they could 
 have fed, or breathed, or moved, or flown. 
 
 What, in fact, are these monstrous fancies, but 
 the incongruous union of parts, which, patched 
 together without order or system, could not have 
 belonged to a living creature. Nor is there any 
 real invention here ; as when the head of a lion is 
 joined to the belly of a goat, or the head of a 
 woman to the body of a bird, or to the tail of a 
 serpent. Of the Centaurs, the Satyrs of the
 
 IMAGINARY ANIMALS. 305 
 
 Indian mountains, the Sphynxes of Egypt, the 
 Griffins among the one-eyed nations, not one 
 could have stood, run, or flown. It may be al- 
 leged that these figures are but allusive repre- 
 sentations mystical types of some country or 
 element ; but it is sufficient to our argument, 
 that they are the only imaginary animals, and 
 are acquiesced in by the classical reader as 
 having a fanciful existence. 
 
 Let us take for our example the Centaur. 
 When we look to the representation in the an- 
 tique marble, the merit of the sculptor is shown 
 in the attempt to reconcile our fancy to the un- 
 natural union of the members. The expansion 
 of the nostrils and the coltish wildness of the 
 expression are indicative of the artist's design, 
 to join the human form to that of the horse. 
 But this could never succeed with him who has 
 been narrowly inspecting the proportions of the 
 horse. If he see in a horse a fore-quarter too 
 heavy, or a long neck and a large head, and 
 observe that these are incompatible with wind 
 and speed, and safe going, and conclude that 
 such an animal must founder in the feet, what 
 would he say to the Centaur, where an addi- 
 tional body, head and shoulders, are made to 
 rest upon the fore-feet ? The subject is classical, 
 at least Galen takes it up, and wonders if Pindar 
 could believe in the Centaurs. " For," says he, 
 " if such an animal were to have existence, is 
 
 B. H H
 
 30(J IMAGINARY ANIMALS. 
 
 ought to have two mouths ; one to correspond 
 with the stomach of man, and the other to masti- 
 cate for the stomach of the horse. If it could 
 run upon the plain, it could not climb the hill, 
 or make its way in rocky places. Though 
 possessed of human faculties, it could not build 
 for itself an habitation, or navigate ships and 
 man the sails;" and more particular still in his 
 objections, he adds, "that it could neither 
 sit like the tailor, nor make shoes like the 
 cobbler." 
 
 But to return to our own argument, we may 
 observe how nature manages to rear a superior 
 incumbent weight upon the fore-quarters, by 
 examining the structure of the skeleton of a 
 Giraffe. There, we see how the pressure is 
 taken off the fore-quarters, by the obliquity of 
 the spine, and the shortness of the hind-legs. 
 However beautiful as works of art, the figures of 
 the Centaurs upon antique gems may be, they 
 are yet monsters, their construction, a joining 
 of inconsistent parts together. 
 
 As a trial of skill, there are few designs more 
 difficult to execute than the representation of 
 a Fawn or Satyr ; because the artist has incon- 
 gruities to reconcile the human form and face, 
 to the limbs of a brute. If we have attended to 
 the size and shape of the human extremities, we 
 see the impossibility of rearing the human trunk 
 upon the legs of a goat the bones are too 
 small, the masses of muscle are displaced. The
 
 IMAGINARY ANIMALS. 307 
 
 painter and the sculptor do not think of this, 
 when they represent their Fawns dancing and 
 piping ; but an instant's thought of the position 
 of the bones, and the action of the muscles must 
 show that they are incapable of such activity. 
 Were such forms actually in being, they must 
 creep weakly on the ground. 
 
 And so of the Griffin : the eagle's wings could 
 never raise the body of a lion. To raise a crea- 
 ture on the wing, there must be a mass of 
 muscle proportioned to the extended wing and 
 a surface of bony texture for the lodgement and 
 attachment of these muscles for flight. The 
 bones of a lion are dense and heavy, and propor- 
 tioned to its muscular strength : and to extend 
 the skeleton, composed of such bones, would 
 never form a creature buoyant in the air. By 
 which we see that, were the external forms con- 
 sistent, there is wanting that internal conforma- 
 tion necessary to the real existence of the animal. 
 The lion's tail, again, would be a very useless 
 appendage, compared with the fine rudder which 
 enables the eagle to direct his swoop. 
 
 These instances might be multiplied ; but we 
 venture to say that every animal form, not ac- 
 tually existing in nature, but the invention of 
 the poet, would be deficient in some balance of 
 the exterior members, or some relation of parts 
 necessary for motion ; and were the exterior and 
 moving parts duly balanced, some internal organ 
 would be found not conformable, or displaced
 
 308 IMAGINARY ANIMALS. 
 
 too much developed, or too much compressed. 
 In short, man's imagination is more limited than 
 we, at first, may have believed ; our inventions 
 are the incongruous union of things seen in 
 nature. It is, indeed, far beyond our power to 
 accomplish what Paley has supposed possible ; 
 for he has said, " that multitudes of conforma- 
 tions, both of vegetables and animals, may be 
 conceived capable of existence and succession, 
 which yet do not exist." This manner of view- 
 ing the subject serves only to confirm us in the 
 belief of the perfection of that natural system of 
 parts which admits the changes necessary to the 
 walking, running, flying, and swimming, of such 
 an infinite variety of creatures, and at the same 
 time accommodates the internal functions, which 
 minister to life, so that they are consistent with 
 every variety of condition to which the animal 
 may be destined.
 
 309 
 
 A COMPARISON OF THE EYE WITH THE HAND. 
 
 IF we are in search of an object which shall 
 excite the highest interest, and at the same time 
 afford proofs of design, we naturally turn to the 
 eye as the most delicate of all the organs of the 
 body : and this suits our present purpose the 
 better, that we have to show how much of 
 the sense of vision depends on the hand, and 
 how strict the analogy is between these two 
 organs. 
 
 From the time of Sir Henry Wotton to the 
 latest writer on light, the eye has been a subject 
 of admiration and eulogy. But I have ventured, 
 on a former occasion,* to say, that this admira- 
 tion is misplaced, while it is given to the ball of 
 the eye and the optic nerve exclusively ; since 
 the high endowments of this organ belong to the 
 exercise of the whole eye, to its exterior appa- 
 ratus, as much as to its humours and the proper 
 nerve of vision. It is to the muscular apparatus, 
 and to the conclusions which we are enabled to 
 draw from the consciousness of muscular effort, 
 
 * See Philosophical Transactions.
 
 310 COMPARISON OF THE EYE 
 
 that we owe that sense by which we become 
 familiar with the form, magnitude, and relations 
 of objects. One might as well imagine that he 
 understood the effect and uses of a theodolite by 
 estimating the optical powers of the glasses, 
 without looking to the quadrant, level, or plumb- 
 line, as suppose that he had learnt the whole 
 powers of the eye by confining his study to the 
 naked ball. 
 
 We must begin our observations by a minute 
 attention to the structure and sensibility of the 
 retina. The retina is the internal coat of the 
 eye ; it consists of a delicate, pulpy, nervous 
 matter, which is contained between two mem- 
 branes of extreme fineness, * and these mem- 
 branes both support it and give to its surfaces a 
 smoothness mathematically correct. The matter 
 of the nerve, as well as these supporting mem- 
 branes, are perfectly transparent during life. In 
 the axis of the eye, there is a small portion which 
 remains transparent, when the rest of the mem- 
 brane becomes opaque, and which has been mis- 
 taken for a foramen,* or hole in the retina. It 
 is surprising, that with all the industry which 
 has been employed to demonstrate the structure 
 of the eye, it is only in the present day that a 
 most essential part of the retina has been dis- 
 covered the membrane of Mr. Jacob. From 
 
 * It is this part which is called the foramen of Soemmerring.
 
 WITH THE HAND. 311 
 
 observing the phenomena of vision, and especially 
 the extreme minuteness of the image cast upon 
 the retina, I had conceived that the whole nerve 
 was not the seat of vision, but only one or other 
 of its surfaces. This could not be well illustrated 
 until the exterior membrane of the retina was 
 demonstrated. But now we see that this mem- 
 brane, when floated in water and under a mag- 
 nifying glass, is of extreme tenuity, and its 
 smooth surface is well calculated to correspond 
 with the exterior surface of that layer of nervous 
 matter which is the seat of the sense. 
 
 The term retina would imply that the nerve 
 constitutes a network : and the expressions of 
 some of our first modern authorities would induce 
 us to believe that they view it in this light, as 
 corresponding with their hypothesis. But there 
 is no fibrous texture in the matter of the nerve ; 
 although, when the retina is floated and torn 
 with the point of a needle, the innermost of the 
 membranes which support the nerve, the tunica 
 vasculosa retince, presents something of this ap- 
 pearance. 
 
 Vision is not excited by light unless the rays 
 penetrate through the transparent retina and 
 reach the exterior surface from within. 
 
 It is well known, that if we press upon the 
 eye-ball with a key or the end of a pencil-case, 
 zones of light are excited. The perception of 
 that light is, as if the rays came in a direction
 
 312 COMPARISON OF THE EYE 
 
 opposite to the pressure. We may say that, in 
 this case, the effect of the pressure is assimilated 
 to that of light ; and as light can strike the part 
 of the nerve which is pressed, only by coining 
 in an opposite direction, the zones of light pro- 
 duced by the mechanical impulse appear in the 
 usual direction of rays impinging upon this part : 
 and consequently, they give the impression of 
 their source being in the opposite quarter. Let 
 us contrast this phenomenon with the following 
 experiment. Let the eyelids be closed, and co- 
 vered with a piece of black cloth or paper which 
 has a small hole in it ; place this hole, not oppo- 
 site to the pupil, but to the white of the eye : 
 then direct a beam of light upon the whole, and 
 this light will be seen in its true direction. Why 
 is there, in these two cases, a difference in the 
 apparent place from which the light is derived ? 
 Is it not that the rays directed upon the eyeball, 
 after striking upon the retina, pierce through it 
 and through the humours of the eye, and im- 
 pinge upon the retina on the opposite side. 
 This explains why the light excited in the 
 eye shall appear to come from different quar- 
 ters : but it does not explain why there should 
 not be a double impression why the beam 
 of light should not influence the retina while 
 penetrating it in the first instance, that is, 
 in passing through it from without inwards, 
 as well as when it has penetrated the humours
 
 WITH THE HAND. 313 
 
 and strikes upon the opposite part of the retina 
 from within outwards. 
 
 Another fact, which has surprised philoso- 
 phers, is the insensibility of the optic nerve 
 itself to light. If it be so contrived that the 
 strongest beam of light shall fall upon the end 
 of the nerve in the bottom of the eye, where it 
 begins to expand into the delicate retina, no 
 sensation of light will be produced. This ought 
 not to surprise us, if I am correct in my state- 
 ment that the gross matter of the nerve is not 
 the organ of vision, but the exterior surface of it 
 only. In the extremity of the optic nerve there 
 is, of course, no posterior surface ; and, indeed, 
 nothing can bettei*prove the distinct office of the 
 nerve itself as contrasted with the expanded 
 retina, than this circumstance, that when the 
 strongest ray of light strikes into the nerve, the 
 impression is not received. It seems to imply, 
 that the capacity of receiving the impression, 
 and of conveying it to the sensorium are two 
 distinct functions. 
 
 Is not this opinion more consistent with the 
 phenomena than what is expressed by one of 
 our first philosophers, that the nerve, at its 
 extremity towards the eye, is insensible, and 
 forms what has been called the punctum ccecum, 
 because it is not yet divided into those almost 
 infinitely minute fibres, which are fine enough 
 to be thrown into tremors by the rays of light.
 
 314 COMPARISON OF THE EYE 
 
 Independently of this punctum coecum, we 
 have to observe that the whole surface of the 
 retina is not equally sensible to light. There is 
 a small spot, opposite to the pupil and in the 
 axis of the eye, which is more peculiarly sen- 
 sible to visual impressions. An attempt has 
 been made to ascertain the diameter of this 
 spot; and it is said, that a ray at an angle of 
 five degrees from the optic axis, strikes exterior 
 to this sensible part. But we shall, on the con- 
 trary, see reason to conclude, that the sensible 
 spot is not limited to an exact circle, that it is 
 not regularly defined, and that the sensibility, in 
 fact, increases to the very centre. 
 
 Some have denied the existence of this ex- 
 treme sensibility in the centre of the retina, 
 attributing the distinctness of vision to the cir- 
 cumstance of the light being made to converge, 
 through the influence of the humours, more 
 correctly to this point. I shall, therefore, show 
 how impossible vision would be, were it not that 
 the sensibility of the retina increases gradually, 
 from its utmost circumference, to the point 
 which forms the axis of the eye. 
 
 We see objects by reflected light, at the very 
 instant that direct light enters the eye. As the 
 impression by the direct light is many times 
 stronger than the reflected rays from the object, 
 the vision of the object would be destroyed by 
 the contrast, were there not this admirable pro-
 
 WITH THE HAND. 315 
 
 vision in the retina, that the direct light shall 
 fall upon a part less sensible, the reflected light 
 upon a part more sensible. If, in full day, and 
 in the open field, the eye be directed southward, 
 the rays from the sun enter the eye at the time 
 that we are looking to certain objects : and it is 
 perfectly clear, that if the sun's rays struck a 
 part of the retina as sensible as the spot in the 
 centre or axis, they would extinguish all se- 
 condary impressions : the glare would be pain- 
 fully powerful, as when we look directly to the 
 sun. If a momentary glance towards the sun 
 produce a sensation so acute that we see nothing 
 for some time after, would not the same happen 
 were the retina equally sensible in all its surface? 
 A similar effect takes place in a chamber lighted 
 with candles ; we do not see the person immedi- 
 ately on the other side of the candle : for there 
 the direct light interferes with the reflected light, 
 effacing the slighter impression of the latter. 
 
 We perceive, therefore, that if the retina were 
 equally sensible over its whole surface, we could 
 not see. Let us, then, observe how we do ac- 
 tually see, and how the organ is exercised. 
 There is a continual desire of exercising the 
 sensible spot, the proper seat of vision. When 
 an impression is made upon the retina, in that 
 unsatisfactory degree which is the effect of its 
 striking any part but the centre, there is an 
 effort made to direct the axis towards it, or, in
 
 310 COMPARISON OF THE EYE 
 
 other words, to receive the rays from it upon the 
 more sensible centre. It is this sensibility, 
 therefore, conjoined with the action of the 
 muscles of the eye-ball, which produces the 
 constant searching motion of the eye ; so that, in 
 effect, from the lesser sensibility of the retina 
 generally, arises the necessity for this exercise 
 of the organ ; and to this may be attributed its 
 high perfections. 
 
 This faculty of searching for the object is 
 slowly acquired in the child ; and, in truth, the 
 motions of the eye are made perfect, like those 
 of the hand, by slow degrees. In both organs 
 there is a compound operation : the impression 
 on the nerve of sense is accompanied with an 
 effort of the will, to accommodate the muscular 
 action to it. It is no contradiction to this, that 
 the faculty of vision is made perfect in the 
 young of some animals from the beginning ; no 
 more than that the instinct of the duck, when it 
 runs to the water the moment that the shell is 
 broken, should contradict the fact that the child 
 learns to stand and walk after a thousand re- 
 peated efforts. 
 
 Let us now see how essential this searching 
 motion of the eye is to vision. On coming into 
 a room, we see the whole side of it at once the 
 mirror, the pictures, the cornice, the chairs ; 
 but we are deceived : being unconscious of the 
 motions of the eye, and that each object is
 
 WITH THE HAND. 317 
 
 rapidly, but successively, presented to it. It is 
 easy to show, that if the eye were steady, vision 
 would be quickly lost : that all these objects, 
 which are distinct and brilliant, are so from the 
 motion of the eye : that they would disappear if 
 it were otherwise. For example, let us fix the 
 eye on one point, a thing difficult to do, owing 
 to the very disposition to motion in the eye : but 
 by repeated attempts we may at length acquire 
 the power of fixing the eye to a point. When 
 we have done so, we shall find, that the whole 
 scene becomes more and more obscure, and 
 finally vanishes. Let us fix the eye on the 
 corner of the frame of the principal picture in 
 the room. At first, every thing around it is dis- 
 tinct ; in a very little time, however, the impres- 
 sion becomes weaker, objects appear dim, and 
 then the eye has an almost incontrollable desire 
 to wander ; if this be resisted, the impressions 
 of the figures in the picture first fade : for a 
 time, we see the gilded frame : but this also be- 
 comes dim. When we have thus far ascertained 
 the fact, if we change the direction of the eye 
 but ever so little, at once the whole scene will be 
 again perfect before us. 
 
 These phenomena are consequent upon the 
 retina being subject to exhaustion. When a 
 coloured ray of light impinges continuously on 
 the same part of the retina, it becomes less 
 sensible to it, but more sensible to a ray of the
 
 COMPARISON OF THE EYE 
 
 opposite colour. When the eye is fixed upon a 
 point, the lights, shades and colours of objects 
 continuing to strike upon the same relative parts 
 of the retina, the nerve is exhausted : but when 
 the eye shifts, there is a new exercise of the 
 nerve : the part of the retina that was opposed 
 to the lights, is now opposed to the shades, and 
 what was opposed to the different colours is now 
 opposed to other colours, and the variation in 
 the exciting cause produces a renewed sensation. 
 From this it appears, how essential the incessant 
 searching motion of the eye is to the continued 
 exercise of the organ. 
 
 Before dismissing this subject, we may give 
 another instance. If we are looking upon an 
 extensive prospect, and have the eye caught by 
 an object at a distance, or when, in expectation 
 of a friend, we see a figure advancing on the 
 distant road, and we endeavour to scrutinize the 
 object, fixing the eye intently upon it, it dis- 
 appears ; in our disappointment we rub the eyes, 
 cast them about, look again, and once more we 
 see the object. The reason of this is very ob- 
 vious : the retina is exhausted, but becomes re- 
 cruited by looking on the other objects of dif- 
 ferent shades and colours. The sportsman on 
 the moor or the hill side, feels this a hundred 
 times when he marks down his covey, fixing his 
 eye and travelling towards the spot.
 
 WITH THE HAND. 319 
 
 Here we may interrupt our inquiry to observe 
 how inconsistent these phenomena are with the 
 favourite hypothesis that light produces vision 
 by exciting vibration in the fibres of the nerve. 
 By all the laws of motion from which this hypo- 
 thesis is borrowed, we know that if a body be 
 set in motion, it is easily kept in motion ; and 
 that if a chord vibrate, that vibration will be kept 
 up by a motion in the same time. It appears 
 to me natural to suppose, that if these fibres of 
 the nerve (which, be it remembered, are also 
 imaginary) were moved like the chords of a 
 musical instrument, they would be most easily 
 continued in motion by undulations in the same 
 time : that if the red ray oscillated or vibrated 
 in a certain proportion of time, it would keep 
 the fibres of the nerve in action more easily, than 
 a green ray, which vibrates in a different time ; 
 and if the colour of a ray depended upon the 
 peculiar undulation or vibration, before the green 
 ray could produce a motion corresponding with 
 itself, it must encounter a certain opposition, in 
 interrupting the motion already begun.* 
 
 * " Although any kind of impulse or motions regulated by any 
 " law may be transferred from molecule to molecule in an elastic 
 " medium, yet in the theory of light it is supposed that only such 
 " primary impulses, as recur according to regular periodical laws, 
 " at equal intervals of time and repeated many times in succession, 
 " can affect our organs with the sensation of light. To put in 
 " motion the molecules of the nerves of our retina with sufficient
 
 320 COMPARISON OF THE EYE 
 
 Reverting to the sensible spot in the retina, 
 it does not appear that we are authorised to 
 term it a spot. The same law governs vision 
 when we look to a fine point of a needle, or 
 to an object in an extensive landscape. We 
 look to the point of a pen, and we can rest 
 the attention on the point upon the one side 
 of the slit, to the exclusion of the other, just 
 as we can select and intently survey a house or 
 a tree. If the sensible spot were regularly 
 
 " efficacy, it is necessary that the almost infinitely minute impulse 
 " of the adjacent ethereal molecules should be often and regularly 
 " repeated, so as to multiply and concentrate their effect. Thus, 
 " as a great pendulum may be set in swing by a very minute 
 " force, often applied at intervals exactly equal to its time of 
 " oscillation, or as one elastic body can be set in vibration, by the 
 " vibration of another at a distance propagated through the air, 
 " if in exact unison, even so we may conceive the gross fibres of 
 " the nerves of the retina to be thrown into motion by the conti- 
 " nual repetition of the ethereal pulses : and such only will be thus 
 " agitated, as from their size, shape, or elasticity, are susceptible 
 " of vibrating in times exactly equal to those at which the impulses 
 " are repeated. Thus it is easy to conceive how the limits of visible 
 " colour may be established : for if there be no nervous fibres in 
 " unison with vibrations more or less frequent than certain limits, 
 " such vibrations, though they reach the retina, will produce no 
 " sensation. Thus, too, a single impulse, or an irregularly re- 
 " peated one, produces no light. And thus also may the vibrations 
 " excited in the retina continue a sensible time after the exciting 
 " cause has ceased, prolonging the sensation of light (especially 
 " if a vivid one) for an instant in the eye in the manner des- 
 cribed." Sir J. F. W. Herschel, Art. Light. Enc. Met. 
 
 Now it does appear to me that this reasoning is inconsistent 
 with the phenomena above noticed.
 
 WITH THE HAND. 321 
 
 defined, it must be very small : and were it, 
 indeed, so defined, we should be sensible of it ; 
 which we are not. The law, therefore, seems to 
 be, at all times, that the nearer to the centre of 
 the eye, the greater is the sensibility to impres- 
 sion ; and this holds whether we are looking 
 abroad on the country, or are microscopically 
 intent upon objects very minute. 
 
 When men deny the fine muscular adaptation 
 of the eye to the sensation on the retina, how do 
 they account for the obvious fact that the eye- 
 ball does move in such just degrees? how is the 
 one eye adjusted to the other with such marvel- 
 lous precision? and how do the eyes move to- 
 gether in pursuit of an object, never failing to 
 accompany it correctly, be it the flight of a bird, 
 or the course of a tennis-ball, or even of a bomb- 
 shell ? Is it not an irresistible conclusion that 
 if we so follow an object, adjusting the muscles 
 of the eye so as to present the axis of vision suc- 
 cessively to it, as it changes place, we must be 
 sensible of these motions ? for how can we direct 
 the muscles unless we be sensible to their action ? 
 The question then comes, to be whether being 
 sensible to the condition of the muscles, and 
 being capable of directing them with this extra- 
 ordinary minuteness, this action of the muscles 
 does not enter into our computation of the place 
 of an object? But is not this exactly the same 
 question recurring as when we asked whether 
 
 B. I I
 
 322 COMPARISON OF THE EYE 
 
 we can direct the hand without knowing where 
 the hand is? Must there not be a feeling or 
 knowledge of the position of the hand, before 
 we can give it direction to an object? And 
 must we not have a conception of the relation 
 of the muscles and of the position of the axis of 
 the eye, before we can alter its direction to fix it 
 upon a new object? 
 
 It surprises me to find ingenious men refusing 
 their assent to the opinion, that the operation of 
 the muscles of the eye is necessary to perfect 
 vision, when the gradual acquisition of the 
 power may be seen in observing the awakening 
 sense in the infant. When a bright object 
 is withdrawn from the infant's eye, there is 
 a blank expression in the features; and an 
 excitement when the object is again presented. 
 For a time, the shifting of the object is not 
 attended with the searching action of the eye : 
 but, by and by, the eye follows it and looks 
 around for it, when it is lost. In this gradual 
 acquisition of power in the eye, there is an exact 
 parallel to the acquisition of motion in the hand ; 
 and in both instances, we seek to join the ex- 
 perience obtained by means of the muscular 
 motion with the impression on the proper nerve 
 of sense. 
 
 Some maintain that our idea of the position of 
 an object is implanted in the mind and inde- 
 pendent of experience. We must acknowledge
 
 WITH THE HAND. 323 
 
 the possibility of this, had it been so provided. 
 We see the young of some creatures with their 
 vision thus perfect at the moment of their birth. 
 But in these animals, every corresponding fa- 
 culty is, in the same manner, perfect from the 
 beginning : the dropped foal, or the lamb, rises 
 and follows its mother. We must no more com- 
 pare the helpless human offspring with the 
 young of these animals than with a fly, the 
 existence of which is limited to an hour at 
 noon, which breaking from its confinement, 
 knows its mate and deposits its eggs on the 
 appropriate tree the willow or the thorn, and 
 dies. But this is foreign to our enquiry ; since 
 it is obvious that the human eye has no such 
 original power of vision bestowed upon it, and 
 that it is acquired, as the exercise of the other 
 senses, and the faculties of the mind itself are, 
 by repeated efforts, or experience. 
 
 If it be admitted that the ideas which we 
 receive through the eye come by experience, 
 we must allow that the mind must be exercised 
 in the act of comparison, before we can have a 
 conception of any thing being exterior to the 
 eye, or of an object being placed in a parti- 
 cular direction. Authors make the matter 
 complex by conceiving a picture to be drawn 
 at the bottom of the eye, and presenting to us 
 the mind contemplating this inverted picture, 
 and comparing the parts of it. But this leaves
 
 324 COMPARISON OF THE EYE 
 
 the subject without any explanation at all, and 
 does not show how it is that the mind looks into 
 this camera. The question will be, at least, 
 more simple, if we consider the vision of a point ; 
 and ask ourselves how we know the direction 
 in which that point comes to the eye. Suppose 
 it is a star in the heavens, or a beacon, seen by 
 the mariner. Must he not, in order to ascertain 
 the position of the star, find out some other object 
 of comparison, some other star, which shall dis- 
 close to him the constellation to which the one 
 that he is examining belongs : or to ascertain 
 the position of the beacon, must he not look to 
 his compass and card, and so trace the direction 
 of the lighthouse in relation to them ? This is, 
 in fact, the process that is followed in every 
 thing which we see. A single point is directly 
 in the axis of the eye, but we cannot judge of 
 its position, without turning to some other point, 
 and becoming sensible of the traversing of the 
 eye-ball and the angle to which the eye is moved : 
 or if we do not see another point to compare the 
 first with, we must judge of its place by means 
 of a comparison with the motion of the eye 
 itself. We are sensible that the eye is directed 
 to the right or to the left ; and we compare the 
 visible impression on the nerve with the motion, 
 its direction, and its extent. 
 
 We find even mathematicians affirming that 
 we judge of the direction of an object by the
 
 WITH THE HAND. 325 
 
 ray that falls upon the retina, and the line in 
 which it comes to the eye. But the ray 
 which is here spoken of strikes a mere point of 
 the retina : this point can have no direction ; 
 the obliquity of the incidence of the ray can 
 inform us of nothing : rays of all degrees of ob- 
 liquity are converging to form that point ; and 
 do not the same mathematicians give us, in the 
 first lessons of their science, as the definition of 
 a line that which is drawn through two points 
 at the least ? Where are the two points here to 
 indicate the direction of the line, since the 
 cornea, or the humours of the eye,* are not 
 sensible to the passage of the ray ? Or is this 
 an error which has crept in from inaccurate 
 conceptions of the anatomy ? Has the idea that 
 the direction of the ray can afford this know- 
 ledge, arisen from the notion that the ray passes 
 through the thick and turbid matter of the 
 retina? I would ask for what reason is the 
 " finder" attached to the great telescope? is it 
 not because the larger instrument, from mag- 
 nifying one object in a high degree, cannot be 
 directed in the heavens the observer seeing 
 with it nothing but that one object? Accord- 
 ingly, to remedy this there is mounted on the 
 greater telescope a smaller one exactly parallel, 
 of lesser power, but commanding a wider field ; 
 
 * See a paper by Mr. Alexander Shaw, who has explained 
 this subject very happily. Journal of the Royal Institution, 1832.
 
 3-26 COMPARISON OF THE EYE 
 
 this " finder" the astronomer directs to the con- 
 stellation, and moves from star to star until the 
 one which he desires to examine is in the centre 
 of the field : and it is by this means that he 
 adjusts the larger telescope to his object. Is 
 this not a correct illustration of the operation of 
 the eye? Is the eye not imperfectly exercised 
 when it sees but one point : on the other hand, 
 is it not in the full performance of its function 
 when it moves from one object to another, 
 judges of the degree and the direction of that 
 motion, and thus enables us, by comparison, to 
 form our judgment ? 
 
 It has been stated by a most ingenious philo- 
 sopher of our time, in opposing these views of 
 the compound nature of the sense of vision, 
 that the forms and relations of objects are 
 known to us by the unassisted operation of 
 the eye-ball itself by the transmission of the 
 rays through the humours of the eye, and 
 by their effect upon the retina ; and he has 
 also affirmed that we should know the position 
 of objects even if the muscles of the eye were 
 paralytic. But I hope that it has been under- 
 stood, when I give so much importance to the 
 motions of the eye, that I do not neglect the 
 movements of the body, and, more especially, the 
 motions of the hand : that, in truth, the measure 
 of objects which we take through the eye, is in 
 correspondence with the experience which we
 
 WITH THE HAND. 327 
 
 have had through the motions of the whole frame ; 
 and that, without such experience, we should 
 have no knowledge of matter, or of position, or 
 of distance, or of form. Were the eye fixed in 
 the head, or paralytic, we should lose a great 
 part of the exercise of the organ, as well as 
 all the appliances which are necessary for its 
 protection : but we should still be capable of 
 comparing the visual impression with the experi- 
 ence of the body. As long as we know the right 
 hand from the left, or must raise our head to 
 see what is above us, or stoop to see a man's 
 foot, there can be no want of materials to form a 
 comparison between the impression on the nerve 
 of sight and the experience of the body. 
 
 Against this view of the compound operation 
 of the eye, the matter is thus argued : if a 
 man receive the impression of a luminous body 
 upon his eye, so that the spectrum shall remain 
 when the eye-lids are shut, and if he be seated 
 upon a stool that turns round, and be whirled 
 round by the hand of a friend, without his own 
 effort, the motion of the spectrum will corres- 
 pond with his own. No doubt it will : because 
 he is conscious of being turned round : a man 
 cannot sit upon a stool that is turning without 
 an effort to keep his place, without a conscious- 
 ness of being turned round ; and feeling, at 
 the same time, that the impression is still 
 before his eye, he will see the spectrum before
 
 328 COMPARISON OF THE EYE 
 
 him, and in that aspect to which he has been 
 revolved. 
 
 Were I not conscious that I am right, I should 
 feel it necessary to make an apology for arguing 
 against the opinions of eminent men on this 
 matter ; but I conceive the explanation of this 
 discrepancy to be, that we are very much influ- 
 enced by the manner in which we approach the 
 examination of such a subject. A man lost in 
 admiration of the properties of light, and of the 
 effect of the humours of the eye as an optical 
 instrument, may be blinded to those inferences, 
 which to me seem so undeniable, accustomed as 
 I have been to compare the properties of the eye 
 with the living endowments of the frame. When 
 instead of looking upon the eye as a mere 
 camera or show -box, with the picture inverted 
 on the bottom, we determine the value of mus- 
 cular activity ; mark the sensations attending the 
 balancing of the body ; that fine property which 
 we possess of adjusting the muscular frame to 
 its various inclinations ; how it is acquired in 
 the child ; how it is lost in the paralytic and 
 drunkard ; how motion and sensation are com- 
 bined in the hand ; how, in this way, the hand 
 guides the finest instruments : when we consider 
 how the eye and the hand correspond ; how the 
 motions of the eye, combining with the impres- 
 sion on the retina, become the means of measur- 
 ing and estimating the place, form, and distance
 
 WITH THE HAND. 329 
 
 of objects the sign in the eye of what is known 
 to the hand : finally, when, by attention to the 
 motions of the eye, we are aware of their extreme 
 minuteness, and how we are sensible to them 
 in the finest degree the conviction irresistibly 
 follows, that without the power of directing the 
 eye, (a motion holding relation to the action of 
 the whole body) our finest organ of sense, which 
 so largely contributes to the developement of the 
 powers of the mind, would lie unexercised.
 
 330 COMPARISON OF THE EYE 
 
 
 
 THE MOTION OF THE EYE CONSIDERED IN RE- 
 GARD TO THE EFFECT OF SHADE AND COLOUR 
 IN A PICTURE. 
 
 A QUESTION naturally arises whether it be pos- 
 sible, from this part of philosophy, to suggest 
 some principles for the amateur and painter. 
 The ideas and language of the amateur, when 
 he attempts to establish rules for the disposition 
 of colours or shades in a picture, are certainly 
 very vague. 
 
 We have to remark, in the first place, that the 
 colours of nature, and those of objects when re- 
 presented in a painting, differ in most essential 
 circumstances. Bodies of various colours, when 
 placed together, have their colours reflected from 
 the one to the other ; and so they come to the 
 eye. This is one mode in which the hues of 
 nature are harmonized ; but the colours upon the 
 flat surface of the canvass cannot be thus re- 
 flected and mingled. The next difference results 
 from the atmosphere, through which the rays 
 from distant objects proceed to the eye and are 
 softened ; the canvass being near the eye, the
 
 WITH THE HAND. 331 
 
 effect which the atmosphere produces on colours 
 amounts to nothing in the picture. The third 
 mode in which colours are affected, is common 
 to natural objects and to paintings, and is con- 
 nected with the law of vision which we have 
 been considering, and to which we must now 
 revert. 
 
 When we make experiments by looking upon 
 coloured spots, the effect on the sensibility of the 
 retina is remarkable ; and as this does not occur 
 incidentally, but takes place more or less, when- 
 ever we exercise the eye, it must have its in- 
 fluence when we look to works of art. The 
 familiar fact which we have to carry with us into 
 this inquiry, is, that if we throw a silver coin 
 upon a dark table and fix the eye upon the 
 centre of it, when we remove the coin there is, 
 for a moment, a white spot in its place, wJiich 
 presently becomes deep black. If we put a red 
 wafer upon a sheet of paper and look upon it, and 
 continue to keep the eye fixed on the same point, 
 upon removing the wafer, the spot where it lay 
 on the white paper will appear green. If we 
 look upon a green wafer in the same manner and 
 remove it, the spot will be red ; if upon blue or 
 indigo, the paper will seem yellow. These 
 phenomena are to be explained by considering 
 that the nerve is exhausted by the continuance 
 of the impression, and becomes more apt to
 
 332 COMPARISON OF THE EYE 
 
 receive sensation from an opposite colour. All 
 the colours of the prism come into the eye from 
 the surface of the white paper when the wafer 
 is removed ; but if the nerve has been ex- 
 hausted by the incidence of the red rays upon 
 it, it will be insensible to these red rays when 
 they are thus reflected from the paper; the 
 effect of the rays of an opposite kind will be 
 increased, and consequently the spot will be 
 no longer white, but of the prevailing green 
 colour. 
 
 Let us see how the loss of sensibility produces 
 an effect in engraving, where there is no colour, 
 and only light and shade. 
 
 Is it possible that a high tower, in a cloudless 
 sky, can be less illuminated at the top than at the 
 bottom ? Yet if we turn to a book of engravings, 
 where an old steeple or tower is represented 
 standing up against the clear sky, we shall find 
 that all the higher part is dark, and that the effect 
 is picturesque and pleasing. Now this is per- 
 fectly correct, for although the highest part of the 
 tower be in the brightest illumination, it is not 
 seen so it never appears so to the eye. The 
 reason is, that when we look to the steeple, a 
 great part of the retina is opposed to the light of 
 the sky ; and on shifting the eye to look at the 
 particular parts of the steeple, the reflected light 
 from that object falls upon the retina, where it is 
 exhausted by the direct light of the sky. If we
 
 WITH THE HAND. 
 
 333 
 
 look to the top of the tower, and then drop the 
 eye to some of the lower architectural ornaments, 
 the effect infallibly is that the upper half of the 
 tower is dark. For example, if looking to the 
 
 point A we drop the eye to B : the tower from A 
 to B is seen by that part of the retina which was 
 opposed to the clear sky from A to C ; and it is 
 dark not by contrast, as it would be thoughtlessly 
 said, but by the nerve being somewhat exhausted 
 of its sensibility. This, then, is the first effect 
 we shall remark as arising from the searching 
 motion of the eye. 
 
 The refreshing colours of the natural landscape 
 are at no time so pleasing as, when reading on 
 a journey, we turn the eye from the book to the 
 fields and woods ; the shadows are then deeper
 
 .'J34 COMPARISON OF THE EYE 
 
 the greens more soothing, and the whole 
 colours are softened. Reynolds observed to Sir 
 George Beaumont that the pictures of Rubens 
 appeared different to him, and less brilliant, on 
 his second visit to the continent ; and the reason 
 of the difference he discovered to be that, on the 
 first visit, he had taken notes, and on the second 
 he did not. The alleged reason is quite equal 
 to the effect ; but I cannot help imagining that 
 there is some incorrectness in the use of the 
 term brilliant, unless warmth and depth of co- 
 louring is meant : for when the eye turns from 
 the white paper to the painting, the reds and 
 yellows must necessarily be deeper. If we look 
 out from the window, and then turn towards a 
 picture, the whole effect is gone the reflected 
 rays from the picture are too feeble to produce 
 their impression ; and if we look upon a sheet of 
 paper, and then upon a picture, the tone will be 
 deeper, and the warm tints stronger, but the 
 lights and shades less distinct. If we place an 
 oil painting, without the frame, upon a large 
 sheet of paper, or against a white plastered wall, 
 it is offensively yellow. Here the eye alternately, 
 though insensibly, moving from the white paper 
 or wall to the painting, which is of a deep tone, 
 the browns and yellows are unnaturally strong. 
 We see the necessity or the effect of the gilt 
 frame for such a picture : it does not merely cut 
 off surrounding objects, but it prepares the eye
 
 WITH THE HAND. 335 
 
 for the colours of the painting it allows, if I 
 may so express it, the painter to use his art 
 more boldly, and to exaggerate the colours of 
 nature. 
 
 Painters proceed by experiment. If they are 
 painting a portrait, they may represent the fea- 
 tures by contrasts of lights and shadows with 
 very little colour ; but such a portrait is never 
 popular. If they are to represent the features 
 without much contrast of light and shade, they 
 must raise the features by contrasts of colours, 
 and the carnations are necessarily exaggerated ; 
 but all this is softened down by throwing a piece 
 of drapery into the picture, and its colours so 
 prepare the eye, that now looking on the fea- 
 tures, that appears natural, which, but for this 
 art, would have represented an inflamed counte- 
 nance. The common resource of the painter is to 
 throw in a crimson curtain, or to introduce some 
 flower or piece of dress that shall lead the eye, 
 by a succession of tints, or, more accurately 
 speaking, shall prepare the eye to receive the 
 otherwise exaggerated colours of the portrait. 
 The eye first surveying the red curtain, and then 
 the countenance, sees it as if coloured only with 
 the modesty of nature. 
 
 Those who hang pictures, do not place an his- 
 torical picture, painted after the manner of the 
 Bolognese school with distinct and abrupt co- 
 loured draperies, by the side of a landscape ; for
 
 3.'M5 COMPARISON OF THE EYE 
 
 the colours of a landscape, to be at all consonant 
 with nature, are weak and reduced to a low 
 tone, by representing that effect, which we ob- 
 served, of the intervention of the atmosphere ; 
 its colours, therefore, would be destroyed by too 
 powerful a contrast. It is difficult to decide 
 what the colour of the walls of a gallery should 
 be, because the pictures are, for the most part, 
 painted on different principles; but generally 
 speaking, the dark subdued red or morone 
 brings out the colours of paintings ; in other 
 words, if we look on a wall of this hue, and then 
 turn to the picture, the prevailing green and 
 yellow tints will appear brighter. 
 
 The word " contrast" is used without a defini- 
 tion, or without an exact comprehension of its 
 meaning. Now the effect of colours, on being 
 placed together, is produced through the motion 
 of the eye, combined with the law of the sensi- 
 bility of the retina, to which we have been ad- 
 verting. When we imagine that we are com- 
 paring colours, we are really experiencing the 
 effect of the nerve being exhausted by dwelling 
 on one colour, and becoming more susceptible 
 of the opposite colour. In coloured drapery, for 
 example, there is such a mixture of all colours 
 reflected from it, although one prevails, that the 
 impression may be greatly modified by what the 
 eye has previously experienced. If the colour- 
 ing of the flesh be, as the painter terms it, too 
 " warm," it may be made " cold" by rendering
 
 WITH THE HAND. 337 
 
 the eye insensible to the red and yellow rays, 
 and more than usually susceptible of the blue 
 and purple rays. Every coloured ray from the 
 flesh is transmitted to the eye ; but if the eye 
 has moved to it from a yellow or crimson dra- 
 pery, then the rays of that kind will be, for the 
 moment, lost to the vision, and the colour of the 
 flesh will appear less warm, in consequence of 
 the prevalence of the opposite rays of colour. 
 
 It ought to be unsatisfactory to the philoso- 
 phical student to make use of a term without 
 knowing its full meaning. There has been a 
 great deal said about contrast and harmony in 
 painting, as resulting from certain colours placed 
 together the idea being that we see these co- 
 lours at the same time whereas, the effect, of 
 which we are all sensible, results from alter- 
 nately looking at the one and at the other. The 
 subject might be pleasantly pursued, but I 
 mean only to vindicate the importance of the 
 motions of the eye to our enjoyment, whether of 
 the colours of art or of nature. 
 
 There is another subject of some interest, 
 namely, the effect produced upon the retina when 
 the eye is intently fixed upon an object, and is 
 not permitted to wander from point to point. 
 This touches on the chiaroscuro of painting ; 
 which is not merely the managing of the lights 
 and shadows, but the preserving of the parts of a 
 scene subordinate to the principal object. There 
 
 B. K K
 
 338 COMPARISON OF THE EYE 
 
 is something unpleasant and imperfect, even to 
 the least experienced eye, in a picture where 
 every thing is made out the drapery of every 
 figure, the carving or ornament of all the objects 
 minutely represented : for these things were 
 never so seen in nature. The true picture, 
 on the other hand, is effective and felt to be 
 natural, when the eye is at once led to dwell 
 on that principal group, or principal figure, 
 with which it is the artist's intention to occupy 
 the imagination. By fine mastery of his art, 
 and by insensible degrees, the painter keeps 
 down the parts which are removed from the 
 centre ; and thus he represents the scene as 
 when, looking intently upon an object, we see 
 that which is near the axis of the eye distinctly 
 the other objects retreating, as it were, or rising 
 out less and less distinctly, in proportion as they 
 recede from the centre. In the one instance, the 
 artist paints a panorama, where on turning round 
 we have presented before the eye the several 
 divisions of the circle, in each of w r hich the 
 objects are equally distinct ; in the other, he 
 paints a picture representing things, not as when 
 the eye, wanders from the one part to the other, 
 but where it is fixed with higher interest upon 
 some central object, while the others fall off 
 subordinately. 
 
 Looking to our main argument, the proofs of 
 beneficence in the capacities of the living 
 frame, we revert naturally to the pleasures
 
 WITH THE HAND. 339 
 
 received through this double property of the 
 eye motion and sensibility ; and whilst we 
 perceive that the varieties of light and shade 
 are necessary to vision, we find that the co- 
 loured rays are also, by their variety, suited to 
 the higher exercise of this sense. They do not 
 all equally illuminate objects, nor are they 
 all equally agreeable to the eye. The yellow, 
 pale green, or Isabella colours, illuminate in 
 the highest degree, and are the most agreeable 
 to the sense ; and we cannot but observe, looking 
 out on the face of nature, whether to the country, 
 the sea, or the sky, that they are the prevailing 
 colours.* The red ray illuminates the least, 
 but it irritates the most ; and it is this variety 
 in the influence of these rays upon the nerve, 
 that continues its exercise, and adds so much 
 to our enjoyment. We have pleasure from the 
 succession and contrast of colours, independently 
 of that higher gratification which the mind 
 enjoys through the influence of association. 
 
 OF EXPRESSION IN THE EYE. 
 
 In the conclusion of the volume I took occa- 
 sion to remark that natural philosophy some- 
 times disturbed the mind of a weak person. 
 I recollect a student who objected to the direc- 
 
 * The Astronomer selects for his telescope a glass which re- 
 fracts the pale yellow light in the greatest proportion, because it 
 illuminates in the highest degree and irritates the least.
 
 340 OF EXPRESSION IN THE EYE. 
 
 tion of the eyes upwards, and the attitude of 
 prayer : " For," said he, " it is unmeaning ; 
 the globe on which we stand is round, and the 
 inhabitants in every degree or division of the 
 sphere have their eyes directed differently, di- 
 verging from the earth, and concentrated to 
 nothing." This foolish observation leads us 
 once more to notice the relations between the 
 mind and the body, and external nature. 
 
 The posture and the expression of reverence 
 are universally the same in every period of 
 life, in all stages of society, and in every clime. 
 On first consideration of this subject, it seems 
 merely natural that, when pious thoughts pre- 
 vail, man's countenance should be turned from 
 things earthly to the purer objects above. But 
 there is a link in this relation every way worthy 
 of attention, and the eye is raised, whether the 
 canopy over us be shrouded in darkness, or 
 display all the splendour of noon. 
 
 The muscles which move the eye-ball are 
 powerfully affected in certain conditions of the 
 mind : independently altogether of the will, the 
 eyes are rolled upwards during mental agony, 
 and whilst strong emotions of reverence and piety 
 are felt. This is a natural sign stamped upon 
 the human countenance, and is as peculiar 
 to man, as any thing which distinguishes him 
 from the brute. The posture of the body fol- 
 lows necessarily, and forms one of those many
 
 OF EXPRESSION IN THE EYE. 341 
 
 traits of expression which hold mankind in 
 sympathy. 
 
 We might bring forward the same evidence 
 here, that we did on a somewhat similar question 
 regarding the expression of the hand, that is to 
 say, the works of the great painters who have 
 made the sublimer passions of man the subjects 
 of their art ; for by the direction of the eyes and 
 the correspondence of feature and attitude, they 
 speak to all mankind. Thus we must admit 
 that the reverential posture, and the upward 
 direction of the eyes are natural to man whether 
 in the darkened chamber or under the canopy 
 of heaven. They result from the very constitu- 
 tion of the mind and body, and are too powerful 
 to be effaced or altered ; no sooner does pain or 
 misfortune subdue a man, or move him to sup- 
 plication, than the same universal expression 
 prevails. Here is the correspondence of the 
 mind, the frame, and external nature, by which 
 man is directed to look for aid from above.
 
 APPENDIX. 
 
 THE 
 
 CLASSIFICATION OF ANIMALS. 
 
 IN EXPLANATION OF THE TERMS INCIDENTALLY USED IN THE 
 VOLUME. 
 
 THE ANIMAL KINGTJOM is arranged in four Divisions: 
 
 Division I. Vertebral Animals : so called from their pos- 
 sessing a vertebral column or spine. 
 
 Division II. Molluscous Animals : such as shell-fish, which 
 are of a soft structure, and without a skeleton. Etym. mollis, 
 soft. 
 
 Division III. Articulated Animals : like the worm or 
 insect : they are without a skeleton, but their skins or cover- 
 ings are divided and jointed. Etym. Articulus, dim. a joint. 
 
 Division IV. Zoophytes : animals believed to be composed 
 very nearly of a homogeneous pulp, which is moveable and 
 sensible, apd resembles the form of a plant. Etym. wov t 
 zoon, a living creature ; <fvrov t phyton, a plant. 
 
 DIVISION I. 
 
 The division of vertebral animals is composed of four Classes : 
 viz., 1. Mammalia, animals which suckle their young. Etym. 
 mamma, a teat. 2. Aves. Etym. avis, a bird. 3. Reptilia, 
 animals that crawl. Etym. from a part of th word repo, to 
 creep. 4. Pisces. Etym. piscis. a fish. 
 
 The first Class Mammalia, is divided into Orders, which are 
 subdivided into Genera, and these are further divided into Species. 
 
 We present the principal Orders with familiar examples. 
 
 Bimana, man. Etym. bis, double; manus, hand.
 
 344 APPENDIX. 
 
 Quadrumana. Etym. quatuor, four ; manus, hand. Mon- 
 keys, makis or lemurs (Etym. lemures, ghosts). The 
 loris tardigradus (tardus, slow ; gradior, to walk) is a 
 species of lemur. 
 
 Cheiroptera. Etym. xf>, cheir, the hand; vripov, pteron, 
 a wing. The Bats. 
 
 Insectivora. Etym. insecta, insects ; voro, to eat. Hedge- 
 hog; shrew; mole. 
 
 Plantigrade. Etym. planta, the sole of the foot ; gradior, 
 to walk. Bear ; racoon. 
 
 Digitigrade. Etym. digitus, the toe, or finger ; gradior, to 
 walk. Lion; wolf; dog; weasel. 
 
 Amphibia. Etym. a/x^>t, amphi, both ; /Stoc, bios, life. 
 Walrus; seal. 
 
 Marsupialia. Etym. marsupium, a pouch. Kangaroo ; 
 
 Rodentia. Etym. rodo, to gnaw. Squirrel ; beaver ; rat ; 
 hare. 
 
 Edentata. Etym. edentulus, toothless: animals without the 
 front teeth. Ai; unau ; armadillo; ant-eater; tamandua; 
 megatherium (^teyae, megas, great ; Stpiov, therion, a 
 wild beast ;) megalonyx (/ueyac, megas, great ; ovv, onyx, 
 a claw) ; ornithorhynchus (opviOoQ, ornithos, of a bird ; 
 pvvxpQ, rhynchos, a beak.) 
 
 Pachydermata. Etym. Tra-)(ye,pachys, thick; dtp^a, derma, 
 skin. Rhinoceros ; elephant ; mammoth ; mastodon 
 (y^aoroe, mastos, a nipple ; oSwv, odon, a tooth) ; Ano- 
 pletherium (avoTrXoc, anoplos, unarmed : dripiov, therion, 
 wild animal) ; Palseotherium (TraXcuoe, palaios, ancient : 
 Orjpiov) ; tapir ; solidungula, as the horse ; couagga. 
 
 Ruminantia. Etym. ruminatio, chewing the cud. Camel ; 
 giraffe ; deer ; goat ; cow ; sheep. 
 
 Cetacea. Etym. cetus, a whale. Dolphin; whale; dugong. 
 
 SECOND CLASS. Aves, or Birds. 
 
 Accipitres. Etym. accipiter, a hawk. Vulture ; eagle ; owl. 
 Passeres. Etym. passer, a sparrow. Lark ; thrush ; swal- 
 low ; crow ; wren.
 
 APPENDIX. 345 
 
 Scansores. Etym. scando, to climb. Parrot; wood-pecker; 
 
 toucan. 
 Gallinee. Etym. gallina, a hen. Peacock ; pheasant ; 
 
 pigeon. 
 
 Grallse. Etym. grallae, stilts. Ostrich ; stork ; ibis ; flamingo. 
 Palmipedes. Etym. palma, the palm of the hand ; pes, 
 
 foot. Swan ; pelican ; gull. 
 
 THIRD CLASS. Reptiles. 
 
 Chelonia. Etym. x^Xvc, chelys, a tortoise. Tortoise; turtle. 
 
 Sauria. Etym. aavpa, saura, a lizard. Crocodile ; alli- 
 gator ; chameleon ; dragon ; pterodactyle (irrepor, pteron, 
 a wing ; SaKrvXoQ, dactylus, a finger) ; ichthyosaurus 
 (i\Qvg, ichthys, a fish ; aavpa, saura, a lizard) ; plesio- 
 saurus (jrXeaiov, plesion, near to ; aavpa, saura, a reptile, 
 resembling a reptile more than a fish) ; megalosaurus 
 (jutyaX?;, megale, great ; aavpa, saura, a reptile) ; iguan- 
 odon ; hylseosaurus (vXrj, hyle, wood or weald, aavpa). 
 
 Ophidia. Etym. <xj>ie, ophis, a serpent. Boa ; viper. 
 
 Batrachia. Etym. ftarpa-^ps, batrachos, a frog. Frog ; 
 salamander ; proteus. 
 
 FOURTH CLASS. Fishes. 
 
 Chondropterygii. Etym. ^ov^pos, chondros, gristle ; Trrepv'6, 
 
 pteryx, the ray of a fin. Ray ; sturgeon ; shark ; lamprey ; 
 
 ammocete (ap,p.og, ammos, sand ; KETOS, cetos, a fish.) 
 Plectognathi. Etym. Tr\tKd),pleco, to join ; yvaQog,gnathos, 
 
 the jaw. Sun-fish; trunk-fish. 
 Lophobranchi. Etym. Xofyos, lopkos, a loop ; fipay%ta, 
 
 branchia, the gills. Pipe-fish ; pegasus. 
 Malacopterygii. Etym. p.a\aKog, malakos, soft; TrrepvZ, 
 
 pteryx, the ray of a fin. Salmon ; trout; cod ; herring; 
 
 remora. 
 Acanthopterygii. Etym. aicavQa, acantha, a thorn ; 7n-pv, 
 
 pteryx, the ray of a fin. Perch ; sword-fish ; mackarel ; 
 
 lophius piscatorius (Xo^ta, lophia, a pennant ; piscator, a 
 
 fisher) ; chaetodon rostratus (^atrr/, chcete, hair ; t>2wv, 
 
 odon, a tooth ; rostratus, beaked) ; zeus ciliaris (cilium, 
 
 an eye-lash).
 
 Al'lM-'.MMX. 
 
 DIVISION II. 
 
 MOLLUSCOUS ANIMALS. 
 
 1st Class. Cephalopoda. Etym. ice^aXi/, cephale, the head ; 
 TroSa, poda, the feet. Animals which have their organs of motion 
 arranged round their head. 
 
 This Class includes Sepia, or Cuttle-fish. Argonauts (Apyw, 
 the ship Argo, vavrijc, nautes, a sailor). Nautilus 
 (vai/rqe, nautes, a sailor). Ammonite, an extinct Cepha- 
 lopode which inhabited a shell resembling that of the Nau- 
 tilus; coiled like the horns of a ram or those on the statues 
 of Jupiter Ammon ; whence the name. Belemnites : also 
 extinct: the shell is long, straight, and conical (pfXtpvov, 
 belemnon, a dart). Nummulites : likewise extinct; whole 
 chains of rocks are formed of its shells ; the pyramids of 
 Egypt are built of these rocks (nummus, a coin). 
 2nd Class. Pteropoda. Etym. irrepov, pteron, a wing ; TroSa, 
 poda, feet ; having fins or processes resembling wings on each 
 side of the mouth. 
 
 The Clio Borealis, which abounds in the North Seas, and is 
 
 the principal food of the whale. 
 
 3rd Class. Gasteropoda. Etym. yam-rip, gaster, the sto- 
 mach ; TroSa, poda, the feet. Animals which move by means of 
 a fleshy apparatus placed under the belly. 
 
 The snail ; slug ; limpet. 
 
 4th Class. Acephala. Etym. a, a, without ; Ke^aXrj, 
 cephale, the head. Molluscous animals without a head. 
 
 The oyster ; muscle. 
 
 5th Class. Brachiopoda. Etym. fipa%iov, brachion, the 
 arm ; irola, poda, the feet. Animals which move by means of 
 processes like arms. 
 
 Lingula ; terebratula. 
 
 6th Class. Cirrhopoda. Etym. cirrus, a lock or tuft of hair ; 
 TroSa, poda, the feet. 
 
 Balanus; barnacle; anatifera (anas, a duck, fero, to bring 
 forth).
 
 APPENDIX. 347 
 
 DIVISION III. 
 
 ARTICULATA. 
 
 1st Class. Annelides, or Vermes. Etym. Annellus, a little 
 ring ; vermis, a worm. 
 
 Leech ; sea-mouse ; earth-worm ; sand-worm ; tubicolae, 
 (tubus, a tube, colo, to inhabit) ; worms which cover 
 themselves, by means of a slimy secretion that exudes from 
 their surfaces, with a case of small shells and pebbles, 
 like the caddis-worm, or with sand and mud. 
 2nd Class. Crustacea. Animals which have a shelly crust, 
 covering their bodies. 
 
 The crabs ; shrimps ; lobsters. 
 
 3rd Class. Arachnida. Etym. apa-%vT)Q, arachnes, a spider. 
 Spiders ; aranea scenica, or saltica, the leaping spider ; the 
 
 scorpion spider ; the mite. 
 
 4th Class. Insecta. They are divided into insects which are 
 without wings and those which have them : and these are further 
 subdivided according to the peculiarities of the wings. 
 
 Aptera (a, a, without ; Trrtpov, pteron, a wing). Centipede 
 
 (having a hundred feet) ; louse ; flea. 
 Coleoptera (/coXtog, coleos, a sheath or scabbard, irrtpov, 
 a wing), insects which have their wings protected by a cover, 
 as the beetle, corn-weevil. Orthoptera (opdoe, orthos, 
 straight, Trrepov), as the locust, grass-hopper. Hemiptera 
 (tl^ttrv, hemisu, half, irrepov}, insects which have one half 
 of their wings thick and coriaceous, and the other mem- 
 branous ; such as a bug, tick, fire-fly. Neuroptera (vtvpov, 
 neuron, a nerve, Trrepov), dragon-fly ; ant-lion ; ephemera. 
 Hymenoptera (v^iev, hymen, a membrane, Trrepov), the 
 bee ; wasp ; ant. Lepidoptera (XeTrte, lepis, a scale, 
 Tn-epov), moth ; butter-fly. Rhipiptera (pnrtg, ripis, a 
 fan, Trrepov), xenos ; stylops. Diptera (<>te, dis, double, 
 , house-fly ; gnat.
 
 348 APPENDIX. 
 
 DIVISION IV. 
 
 ZOOPHYTES. 
 
 Echinodermata (Etym. cxtvoc, echinos, a hedgehog ; tep/m, 
 derma, the skin), the star-fish ; sea urchin. Entozoa 
 (ttroc, entos, within; aw, zao, to live), teenia; hydatid. 
 Acalephce (<z;aX>^i?, acalephe, a nettle), medusa ; polypi 
 (containing much sap) ; sea-anemone ; hydra ; tubipora 
 (inhabiting tubes) ; sertularia ; cellularia ; flustra ; coral- 
 line, sponge. Infusoria (found in infusions or stagnant 
 water), monas ; vibrio ; proteus. 
 
 THE END. 
 
 C. WH1TTINOHAM, TOO IS col RT, ( HA.Nt Kl( V LAM
 
 
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