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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-
doms ; the effect of digestion, and thereby of conversion ;
the construction of the hand of man, and an injinite variety
of other arguments ; as also by discoveries ancient and
modern, in arts, sciences, and the whole extent of literature.
He desired, moreover, that the profits arising from the sale
of the works so published should be paid to the authors of
the works.

The late President of the Royal Society, Davies Gilbert,
Esq. requested the assistance of his Grace the Archbishop
of Canterbury and of the Bishop of London, in determining
upon the best mode of carrying into effect the intentions of
the Testator. Acting with their advice, and with the con-
currence of a nobleman immediately connected with the
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.

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.

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.

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.

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

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.

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.

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.

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.

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

lANTA (AltSAHA *

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