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THE HAND,
ITS MECHANISM AND VITAL ENDOWMENTS,
AS EVINCING DESIGN.
BY
SIR CHARLES BELL, K. G. H.
F.R.S. L. & E.
NEW-YORK:
"UBLISED BY HARPER & BROTHERS,
NO. 82 CLIFF-STRIET.
1840,


Phil 4581.10.4.5
MANDARD COLLEGE LIBRARY
Dei
1852 Soki 18


THE BRIDGEWATER TREATISES
ON THE POWER, WISDOM, AND GOODNESS OF GOD
AS MANIFESTED IN THE CREATION.
TREATISE IV.
THE HAND, ITS MECHANISM AND VITAL ENDOWMENTS,
AS EVINCING DESIGN.
BY SIR CHARLES BELL, K. G. 8. F. R. S. L. & E.





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, bearing date the 25th of February, 1825,
be directed certain Trustees therein named to invest in the public funds
the sum of Eight thousand pounds sterling : this sum, with the ac-
cruing 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
Or the Power, Wizdo:n, and Goodness of Gol, as manifeste:t in the
Creation ; illustrating such work by all reasonable arguments, as for in-
stance the rariety an:formation of God's creatures in the animal, vege-
table, and mineral kingdoms; the effect of digestion, and thereby of con-
version ; the construction of the hand of man, and an infinite variety of
other argumen!s ; as also by discoveries ancient and modern, in arts,
sciences, and the rohole 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 concurrence of a nobleman immediately con.
nected with the deceased, Mr. Davies Gilbert appointed the follow-
ing 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 THE UNIVERSITY OF EDINBURGH.
ON THE ADAPTATION OF EXTERNAL NATURE TO THE MORAL
AND INTELLECTUAL CONSTITUTION OF MAN.
JOHN KIDD, M. D. F. R. S.
REGIUS PROFESSOR OF MEDICINE IN THE UNIVERSITY OF OXFORD.
ON THE ADAPTATION OF EXTERNAL NATURE TO THE
PHYSICAL CONDITION OF MAN.


viií
PREFACE.
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 fur-
ther honour of asking him to join with him in illustra-
ting the “ Natural Theology” of Dr. Paley.
That request was especially important, as showing,
that the conclusions, to which the author had arriv-
ed, were not the peculiar or accidental suggestions of
professional feeling, nor of solitary study, which is so
apt to lead to enthusiasm, but that the powerful and
masculine mind of Lord Brougham was directed to
the same object : that he, who in early life was dis-
tinguished for his successful prosecution of science,
and who has never forgotten her interests amidst
the most arduous 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 gradually drawn the au.
thor to support these opinions more ostentatiously and
elaborately than was his original wish.
The author cannot conceal from himself the disad-
vantages to which he is exposed in coming before the
public, not only with a work, in some measure extra.
professional, but with associates, distinguished by


PREFACE.
classical elegance of style, as well as by science. He
must entreat the reader to remember that he was, ear-
ly 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 negligent 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
unfavourably contrasted with what comes of the
learned leisure of a College.
The author has to acknowledge his obligation to
Davies Gilbert, Esq. late President of the Royal Socie-
ty, for having assigned to him a task of so much inter-
est. 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.
CHAP. I. INTRODUCTORY
.
.
.
.
.
Caap. II. DEFINITION OF THE HAND .
..
Its Mechanism
. . . . .
Conformity of the Skeleton to the Extremity . .
Bones of the Extremity not adapted to Man alone .
Fossil Bones exhibit the Extent of the System . .
Animals the most uncouth, in every Respect adapted to
their Condition or . . . . .
Mistaken Compassion for Animals
Animals suited to the progressive Changes of the Earth
and Elements. .
Succession and Grouping of Animals . . .
32
39
Chap. III. The Comparative Anatomy OF THE HAND .
Comparative View of the Anatomy of the Shoulder .
The Arms wanting in a Boy
The Structure of the Horse's Shoulder .
In the Chelonian Order
The Humerus. Spirit in which the Demonstration should
be given . . . . . .
Peculiarities in the Mole
Bat . . . . . .
Ant-Eater .
Adaptation of the Anatomy in Birds
The Anatomy of the Fore Arm .
The Action of the Splint Bone in the Horse ..
Horse's Foot
........


CONTENTS.
The Hoofs of Animals and their Sensibility
.
Pago
140
145
CHAP. IX. OF THE MUSCULAR SENSE.
· Of the Sensibility of the Infant to Impressions, and gra-
dual Improvement of the Sense of Touch .
Of the same in Insects and Fishes . . .
Loss of the Sense. . .
Pleasures arising from the Muscular Sense
146
152
153
154
157
Chap. X. THE HAND NOT THE SOURCE OF INGENUITY
OR CONTRIVANCE, NOR CONSEQUENTLY OF Man's
SUPERIORITY
The Subject illustrated by the Organs of Speech :
The Ingenuity of the Hand has made a Revolution in
- the Arts
Changes in the Globe and successive Epochs . .
CONCLUSION . . . . . . .
161
162
164
168
ADDITIONAL ILLUSTRATIONS.
171
THE MECHANICAL PROPERTIES OF THE SOLID STRUCTURE OF
THE ANIMAL BODY CONSIDERED
Substitute for the Skeleton in the lower Animals .
Mechanical Properties in Bone, or in the true Skeleton.
The Muscular and Elastic Forces . . .
172
175
181
183
COMPARISON OF THE EYE WITH THE HAND .
The Motion of the Eye considered in regard to the Ef-
fect of Light and Shade in a Picture
197
ADDITION TO THE CONCLUDING
PTER
.
.
204
ADDITION TO THE CONCLUDING CHAPTER
APPENDIX,
Explanation of Terms . .
.
.
..
10





THE HAND,
ITS MECHANISM AND VITAL ENDOW.
MENTS, AS EVINCING DESIGN.
CHAPTER I.
If we contemplate any natural object, especially
any part of animated nature, fully and in all its bear.
ings, we can arrive only at this conclusion: that there
is design in the mechanical construction, benevolence
shown in the living properties, and that good predo-
minates: we shall perceive that the sensibilities of
the body have a relation to the qualities of things
external, and that delicacy of texture is a necessary
consequence of this relation.
Wonderful, and exquisitely constructed, as the me.
chanical appliances are for the protection of this deli-
cate structure, they are altogether insufficient; and
ą protection of a very different kind, which shall ani.
mate the body to the utmost 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 us onward, through
the developement and improvement of the mind itself,
to higher aspirations,


16
INTRODUCTORY CHAPTER.
Such is the course of reasoning which I propose to
follow in giving an account of the hand and arm, con-
trasting them with the corresponding parts of living
creatures, through all the divisions of the chain of
vertebrated animals.
When I first thought of extending my notes on this
subject, it appeared to me that I might have many
other topics more prolific in proofs of design, and more
interesting; but I now find that there is no end to
illustration, and that the subject branches out inter-
minably.'
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 consider-
ing it in that light. I embark fearlessly in the inves-
tigation, 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 me-
chanism of the animal body.
Let us for a moment think what is the natural re-
sult of examining the human body as a piece of ma-
chinery, 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 machine
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 multiply-
ing 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 power of the hand; and if the mechani-
cian 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


18
INTRODUCTORY CHAPTER.
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-powerful Being
should manifest his will in this manner; that mecha-
nical contrivance implies difficulties overcome : and
how strange it is, they add, that the perceptions of the
mind, which might have been produced by some di-
rect 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 tó con-
template 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 en-
titled 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 form-
ation of the aromatic and volatile principles, and to
fructification, its influence on the animal surface by
invigorating the circulation, and imparting health.
In relation to our present subject, it seems more ra-
tional to consider light as second only to attraction,
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 suffi-
cient to say that it moves 200,000 miles in a second ;
for we can comprehend no such degree of velocity.
If we are 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 1-8th, it is but


20
INTRODUCTORY CHAPTER.
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, ,'.
Something, then, we observe to be common to our
planet and to others, to our system and to other sys-
tems; 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 himself at home in any other, that
he would be like a traveller only, for a moment per-
plexed by diversity of climate and strangeness of man-
ners, 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 mecha.
nical construction of animals, as in their endowments
of life, they are created in relation to the whole, planned
together and fashioned by one Mind.
The passiveness which is natural in infancy, and
the want of reflection as to the sources of enjoyment
which is excusable in youth, become insensibility and
ingratitude in riper years. In the early stages of life,
before our minds have the full power of comprehen-
sion, 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 contem-
plate them; that mind which is now strengthened by
experience to comprehend them, and to entertain
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


INTRODUCTORY CHAPTER.
21
continue, become the sources of all the endearing re-
lations of life, and the very bonds by which society is
connected."
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 universally con-
demned 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 provide,
but which he can hardly comprehend, while he pro-
fits 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 provisions
are made. If the vital actions of a man's frame were
directed by his will, they are necessarily 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 functions are governed through means
and by laws which are not dependant on his will, and
to which the powers of his mind are altogether inade-
quate. For had they been under the influence of his
will, a doubt, a moment's pause of irresolution, a for-
getfulness 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


22
INTRODUCTORY CHAPTER.
! 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 pas-
sion, we perceive the benevolent design in withdraw-
ing the vital motions from the influence of such capri-
cious 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 or
As some superintendant intelligent being, for what else
“should put the diaphragm and the muscles serving
“ respiration in motion all of a sudden so soon as ever
56 the fætus is brought forth? Why could they not
6 have rested as well as they did in the womb ?
6 What aileth them that they must needs bestir them-
“selves to get in air to maintain the creature's life?
"Why could they not patiently suffer it to die? You
s will say the spirits do at this time flow to the or-
“gans of respiration, the diaphragm, and other mus-
“cles which concur to that action and move them.
“But what raises the spirits which were quiescent,
66&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 endowments worse than ingrati-
tude? In a rational creature, ignorance of his condi-
tion becomes a species of ingratitude ; it dulls his sense


INTRODUCTORY CHAPTER.
23
of benefits, 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 inattention,
and lost to all sense of the benevolence of the Crea-
tor, he is roused to reflection only by overwhelming
calamities, which appear to him magnified and dis-
proportioned ; and hence arises à 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 themselves 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 unwillingness to contemplate the superiority
or dignity 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 an-
swered so instantly, as if the hand itself were the seat
of that will ; its actions are so 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 sub-
servient to the mind; we use it as we draw our breath,
unconsciously, 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 pero
fection of the instrument which makes us insensiblo


24
INTRODUCTORY CHAPTER.
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 obser-
vations, 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 con-
scious, or, at least, without any conception of the thou-
sand 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 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 essay, I shall take up the subject
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 properties, I shall advance to the subject of
sensibility, leading to that of touch; afterwards, I shall
show the necessity of combining the muscular 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 corre.
spondence between the capacities and endowments
of the mind, in comparison with the external organs,


INTRODUCTORY CHAPTER.
25
and more especially with the properties 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 all animated nature, and which
has prevailed in the earliest condition of the world ;
and that, finally, in the most minute or most comprè-
hensive study of those things we every where see
prospective design.


NOT ADAPTED TO MAN ALONE.
29
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 comprehensive 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 per-
ceptible, the same bones are adjusted to every condi-
tion of animal existence.
We recognize the bones which form the upper ex-
tremity 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 mo-
tion in the hoof of the horse, or in the foot of the camel,
or adjusted for climbing or digging in the long clawed
feet of the sloth or bear. i
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 present-
ing the most perfect combination of parts: as exhibit-
ing the parts, which in different animals are suited to
particular purposes, so combined in the hand, as to
perform actions the most minute and complicated,
consistently with powerful exertion.
The wonder still is, that whether we examine this
system in man, or in any of the inferior species of ani-
mals, nothing can be more curiously adjusted or ap-
propriated; and we should be inclined to say, what-
ever 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 un-
bounded. The curous synthesis by which we ascer.
tain the nature, condition, and habits of an extinct
animal, from the examination of its fossil remains, is
grounded on a knowledge of the system of which we
are speaking. A bone consists of many parts; but
for our present purpose it is only necessary to observe


30
FOSSILIZED BONES SHOW
that the hard substance, the phosphate of lime, which
we familiarly recognize as bone, is every where pene-
trated by membranes and vessels as delicate as those
which belong to any other part of the body. Some
bones are found with their animal part remaining,
others are fossilized. The phosphate of lime loses its
phosphoric acid, and the earth of bone remains incor-
ruptible, while the softer animal matter undergoes the
process of decomposition, and is dissipated. The bone
in this condition may become fossilized; silicious earth,
or lime in composition with iron, or iron pyrites, may
pass by infiltration into the interstices of the original
earthy matter, and in this state it is as permanent as
the solid rock. It retains the form, though not the
internal structure of bone; and that form, in conse-
quence of the perfect system which we have hinted
at, becomes a proof of revolutions the most extraordi-
nary. 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 bones of large animals and in great variety
are found imbedded in the surface of the earth.
They are discovered in the beds of rivers, they are
found where no waters flow, they are dug up from
under the solid limestone rock. The bones thus
exposed, become naturally a subject of intense in-
terest, and are unexpectedly connected with the en-
quiry in which we are engaged. Among other im
portant conclusions they lead to this that there is
not only a scheme or system of animal structure per-
vading 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 animals which existed previous to the revo.
lutions 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 EXTENT OF THE SYSTEM.
31
the earth was prepared for him or suited to his consti-
tution, structure, or capacities.
A skeleton is dug up which has lain under many
fathoms of rock : being the bones of an animal
which 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 elements, 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 system, and
were moved by the action of muscles—that their or-
gans of digestion, circulation, and respiration were
modified by circumstances, as in the animals now alive,
and in accordance with their habits and modes of liv-
ing. The changes in the organs are but variations in
the great system by which new matter is assimilated
to the animal body,--and however remarkable 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 ancient world, so
regularly are they formed on the same principle which
is evident in the animals now inhabiting the earth,
that on observing their shape, and the processes by
which their muscles were attached, we can reduce
the animals to which they belonged, to their orders,
genera, and species, with as much precision as if the re-
cent bodies had been submitted to the eye of the ana-
tomist. 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 ani-
mals, 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 lacertæ,
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


ANIMALS THE MOST UNCOUTH
creation, the surface of the earth would have been
unsuitable to him.
On comparing some of the present races of animals,
with the fossil remains of individuals of the same
family, some singular opinions on their imperfections
have been expressed by Buffon, and adopted by Cu-
vier. The animals I allude to are of the tardigrade
family; the Ai,* in which, as they believe, the defect
of organizaton is the greatest; and the Unau,+ which
they consider only a little less miserably provided for
existence.
Modern travellers express their pity for these ani
mals : 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 con-
spire 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 strong
arms,--and if he can hook on his claws to the ine-
qualities of the ground, he drags himself along. This
is the condition which authorizes such an expression
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 philosophers
for animals, I which they consider imperfectly organ-
* Bradypus Tridactylus :-bradypus (slovo footed,) tridactylus (three
toed,) of the order EDENTATA (wanting incisor teeth.)
| Bradypus didactylus.
| The subject is pursued in the end of the following chapter.


SUITED TO THEIR CONDITION.
33
ized, is uncalled for ; as well might they pity the
larva of the summer fly, which creeps in the bottom
of a pool, because it cannot yet rise upon the wing.
As the insect has no impulse to fly until the meta-
morphosis is perfect, and the wings developed, so we
have no reason to suppose that a disposition or instinct
is given to animals, where there is no corresponding
provision for motion.
The sloth may move tardily on the ground, his long
arms and his preposterous claws may be an incum-
brance, 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 ene-
mies.
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 catching a fly, is so ra-
pid 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 surrounding objects.
Whilst other animals have excitement conforming to
their rapid motions, the shrivelled face of the chame-
lion hardly indicates life; the eyelids are scarcely
parted; he protrudes his tongue with a motion so
imperceptible 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 were not the
very means bestowed upon it as necessary to its
existence. It steals on its prey by night, and ex-
tends its arm to the bird on the branch, with a
motion so imperceptibly slow, as to make sure of its


34
MISTAKEN COMPASSION FOR
object.* 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 so gentle a motion 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 necessities
or vicious desires of man subjugate him, and make
him acquire, by practice, the wiliness which is im-
planted as instinct in brutes ; or we may say that
in our reason we are brought to imitate the irrational
creatures, and so to vindicate the necessity for their
particular instincts, of which every class, affords an
instance. We have examples 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 slow motions
* 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 have a coat like animals of the arctic regions.
What is this, but to clothe them, as the sentinel is clothed, whose
watch is in the night. They have eyes too, which, from their peculiari-
ty, are called nocturnal, being formed to admit a greater pencil of rays.
For this purpose the globe is large and prominent, and the iris con-
tractile, to open the pupil to the greatest extent.-We have seen
how all their motions and instincts correspond with their nocturnal
habits.
| 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 without 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 to-
wards 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 ar-
rived within due distance, swift as lightning she made the fatal leap,
and secured her prey."-Evelyn, as quoted by Kirby and Spence.


ANIMALS OF PECULIAR FORM.
35
of the muscles of animals ; that we are not to‘ac-
count this a defect, but rather an appropriation of
muscular power. Since in some animals the same
muscles which move their members in a manner 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 de-
fect of organization; as attempts of nature in which
she has failed to perfect her plan ; that she has pro-
duced animals 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 favorably, when he says of the existing species,
that they have so little resemblance to the organiza-
tion 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 present system of nature ; and if we
are to look for their congeners, it must be in the inte-
rior of the earth, in the ruins of the ancient world.
· The animals of the Antediluvian world were not
monsters; there was no lusus or extravagance.
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 have the ichthyosaurus and megalosaurus, and
igùanodon, pterodactyles, with long and short beaks,
tortoises, and crocodiles; and these are found among
reeds and grasses of gigantic proportions, alga and
fuci, and a great variety of mollusca of inordinate
bulk, compared with those of the present day, as am-
monites and nautili. Every thing declares, that
these animals 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 per-


36
MAN SUITED TO THE PRESENT.
pendicular rocks bound in the seas; but that it was
flat, slimy, and covered with a loaded and foggy
atmosphere. There is, indeed, every reason to believe
that the classes mammalia and birds. were not then
created, and that if man had been placed in this con-
dition of the earth, there must have been around him
a state of things unsuited to his constitution, and not
calculated to call forth his capacities.'
But looking to the class of animals 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 obtain in higher animals since created, with
infinitely varied instincts and powers for defence or
attack.
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 val-
leys, 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 revolutions, whether
they have been slowly accomplished 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...,


GROUPING OF ANIMALS.
39
If the naturalist or geologist, exploring the rocks
of secondary formation, should find inclosed within
them animals of the class Molusca, 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 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 in-
stincts, organization, and instruments of animals on
the one hand, and the element in which they are to
live, the position which they 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 this subject of the progressive im-
provement of organized beings, it is affirmed that the
last created of all, man, is not superior in organiza-
tion to the others, and that if deprived of intellectual
power he is inferior to the brutes. I am not arguing
to support the gradual developement and improve-
ment 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 constitutional
property which enables him to fulfil his destinies by


40
OF THE SUCCESSION AND
extending his race in every, climate, and living on
every variety of nutriment. Gather together the
most powerful brutes, from the artic circle or torrid
zone, to some central point—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 provisions of his body, it is no
doubt true ;-but as we proceed, we shall find how
the Hand supplies all instruments, and by its corres-
pondence with the intellect gives him universal do-
minion. It presents the last and best proof of that
principle 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 exercise ; but that the circum-
stances in which the animal has been placed, have
been 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 animal which was at first simple. We
shall reserve the discussion of this subject until we
have the data before us;, which, of themselves, and
without much argument, will suffice to overthrow it.
I may notice here another idea of naturalists, who
are pleased to reduce these changes 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 surpris-
ing variations of form. If this be a law, there is no
more to be said about it, the enquiry is terminated.
But I contend 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
extremities and comparative permanence towards the
centre of the skeleton ? I conceive the rationale to
be this, that the central part, by which in fact they
mean the skull, spine, and ribs, are permanent in


GROUPING OF ANIMALS.
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 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 extremities must be adapted to their
various actions, and the carpus and phalanges 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 ?
There is yet another opinion, which will suggest
itself by the perusal of the following chapter, 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 attributable to the transposition and
moulding of these elementary parts. I find it atterly
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 tri,
fling pursuits,mand 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.


COMPARATIVE ANATOMY
Were it my purpose to teach the elements of this
subject, I should commence with 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 illus-
tration only, I shall begin with the human hand, and
compare its parts. With this view, I shall diyide
the extremity into the shoulder, arm, and hand, and
treat each subdivision with a reference to its structure
in animals.
In viewing the human figure, or human skeleton,
in connection with our present subject, we 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 ani-
mal, but the pelvis is wider, and the obliquity of the
neck of the thigh-bone greater. The distances of
the large processes 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 upright posture, and
give him the perfect freedom of the arms, for pur-
poses of ingenuity and art.
The Chimpanzee* is an ape which stands high in,
* Simia troglodytes, from the coast of Guinea, more human in its
form, and more easily domesticated than the ouràng-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; in the Coaita we see the
great toe assuming the characters of a thumb, whilst in the fore paw,
the thumb is not distinguishable, being hid in the skin. In short,
these paws are not approximations to the hand, corresponding with
a higher ingenuity, but are adaptations of the feet to the branches
on which the animals climb.


OF THE SHOULDER.
45
the order of quadrumana, yet we cannot mistake his
capacities : that the lower extremities and pelvis, or
hips, were never intended to give him the erect pos-
ture, 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 consequent
squareness of the trunk, are equally distinctive 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
extraordinary degree of intricacy. We shall; how-
ever, find that they retain their proper office, notwith-
standing the strange variations in the form of the
neighbouring parts. In man they are directly con-
nected with the great apparatus of respiration ; but
in other animals we shall see the ribs, as it were,
withdrawn from them, and the bones of the shoulder,
or fundamental bones of the extremity, 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 that which is most familiar and easy, the
shoulder of man'in comparison with the varieties in
the mammalia.
The clavicle, or collar bone, is that which run
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


46
COMPARATIVÈ ANATOMY
the action of the muscles upon the arm bone, which,
but for it, would be drawn inwards, and contract the
upper part of the trunk.
E B

B
D-
If we take the motions of the anterior extremity
in different animals, as our guide, we shall see why
this bone is perfect in some, and entirely wanting in
others. Animals which fly, 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
degree 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 extensively, 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,
however imperfect, it marks a correspondence in the
A. Triangular portion of the Sternum. B. B. Clavicles. .c. c.
Scapulæ. D. Coracoid process of the Scapula. E. Acromion pro.
cess of the Scapulæ.


OF THE SHOULDER.
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, 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 keeper's 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, although harmless in disposition,
he can squeeze his enemy, the jaguar, to death.
These actions, and the power of climbing, result from
the structure of the shoulder, or from possessing a
collar bone, however imperfect..
Although the clavicle is perfect in man, thereby
corresponding with the extent and freedom of the
motion of his hand, it is strongest and longest, com-
paratively, 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 pre-
served 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 cla-
vicle, and possessing that bone and the corresponding
motions, is not without means of defence ; for with
the anterior extremities 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, and, as we
should suppose, totally defenceless, nature has no
been negligent of his protection. *
* There is in the form of the kangaroo, and especially in its skele-
ton, something incongruous, and in contrast with the usual shape of
quadrupeds. The head, trunk, and fore paws, appear to be a por-
tion of an animal, unnaturally joined to another of greater dimensions
• and strength. It is not easy to say what are, or what were, tha puso


48
COMPARATIVE ANATOMY
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 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, corresponds with the form and place of the
clavicle; and if we so consider it, we may then take
rior relations corresponding with the very peculiar form of this
animal; but the interior anatomy is accommodated, in a most remark-
able manner, to the enormous hinder extremities.
The uterine system of the female is diminutive, and does not under-
go the developement, which universally takes place in other animals.
The young, instead of remaining within the mother for the period of
gestation, become, by some extraordinary mode of expulsion, attached
to the teats; where they hang by the mouth, covered by an exterior
pouch, until, from minute and shapeless things, they are matured to
the degree in which the young of other animals are usually produced.
The artery which supplies the milk glands, is the epigastric, a branch
of the great artery of the thigh ; and in this curious manner is the
provision for the young drawn from the great limbs of the mother,
certainly the part best enabled to supply it.
I think I perceive the reason of this very peculiar manner of bring-
ing forth the young, to be in the form of the animal and its upright
position. The argument would stand thus, were we here at liberty
to discuss it: 1. An upright position of the mother requires a pelvis
of a peculiar and complex construction, 2. A pelvis, of this construc-
tion, requires that the form of the offspring shall accurately corres-
pond, and that the anterior part of the fætus shall much exceed in
size the posterior parts. 3. But the kangaroo is, in shape, the very
reverse,--the head could not, consistently with the conformation of
the whole animal, be larger than the hips and hinder extremities. 4.
Nature has accomplished her work safely, and by the simplest
means, by anticipating the period of the separation of the fætus, and
providing for the growth of the offspring, exterior to the circle of
bones through which its birth must take place. It will, perhaps, be
objected to this reasoning, that the order didelphis (with a double
womb) embraces animals which have no such remarkable dispro-
portion in the hinder extremities.


OF THE SHOULDER.
the strong bone, commonly called the clavicle, as a
process of the irregularly formed scapula. However
this may be, what we have to admire in birds, is the
mode in which the bones are fashioned, to strength-
n the articulation of the shoulder, and to give extent
f surface for the attachment of muscles.
Another peculiarity in birds is, that there is not an
alternate motion of the wings; their extremities, as
we may continue to call them, move together in fly-
ing; and, therefore, the clavicles are joined, forming
the furculum.
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, which lying
on the ribs, and cushioned with muscles, 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
scapulæ on the motions of the arm, I shall give an
instance in proof of a very important function which
they perform. Hearing that there was a lad of four-
teen years of age, born without arms, I sent for him.
I found that indeed he had no arms, but he had cla-
vicles and scapulæ. When I made this boy draw his
reath, the shoulders were raised, that is to say, the
capulæ were drawn up, were fixed, and became the
points from which the broad muscles of the chest
diverged towards the ribs, to draw and expand them
in respiration. We would do well to remember this
double office of the scapula and its muscles, that


HORSE'S SHOULDER.
51
they were as powerful as the posterior extremities,
they would suffer fracture or dislocation. We can-
not but admirė, therefore, the provision in all quad-
rupeds whose speed is great, and whose spring is
extensive, that, from the structure of their bones,
they have an elastic resistance, by which the shock
of descending is diminished.
If we observe the bones of the anterior extremity
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 through a solid column, and the
bones of the foot, or the joints, would suffer from the
concussion. 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 connection between
the shoulder and the trunk, so 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 scapulæ 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 understand 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 ab-
ruptness, or prominence of the shoulder, is a conse-
quence 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'S SHOULDER.
53
power in bending it; but as we bend it the power is
increased; which is owing to the change in the direc-
tion of the force acting upon the bone; or, in other
words, because the tendon becomes more perpendi-
ular to the lever. A scapula which inclines ob-
quely backwards, increases the angle at which it
ies with the humeruș, and, consequently, improves
the effect of those muscles which pass from it to the
humerus. We have only to turn to the skeleton o
the elephant, the ox, the elk, or the stag, to see the
confirmation 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, conse-
quently, its obliquity in reference to the radius and
ulna, the power of the muscle inserted (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 ani-
mal 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 off 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,
The leg of the elephant is obviously built for the
purpose of sustaining the huge bulk of the animal,
whilst in the camel we have a perfect contrast.
Were we to compare the bones of these larger
animals with any form of architecture, we might
say, it was the Egyptian, or rather like the Cyclo-
pean walls of some ancient city; they are huge and
shapeless, and piled over each other, as if they were
5*


54
COMPARISON OF THE BONES
destined more to sustain the 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 character, 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 mammalia, they constitute an
important part of the organ of respiration; and they
conform to the structure of the thorax. But we
shall find that in some animals, this function is in a
manner withdrawn from them; the scapulæ 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 batrachian 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 mamma-
lia. Accordingly, we find that the bones of the
shoulder are on a new model; they form a broad
and flat circle, sufficient to give secure attachment to
the extremity, and affording a large space for the
lodgment of the muscles which move the arm.-
Perhaps the best example of this structure is in the
siren and proteus; where the ribs are reduced to a
very few imperfect processes, attached to the ante-


56
COMPARATIVE ANATOMY
strange if, now being joined for the purpose of giving
attachment to the humerus, and in circumstances,
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 the figure on
the preceding page, we have the bones of the shoul-
der of the turtle ; and it is readily perceived 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.
În 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 appen-
dage, is, in fact, attached to the bones of the head.
So that the whole consists of a circle of bones, which,
we may say, seek security of attachment by approach-
ing the more solid part of the head, in defect of a
firm foundation in the thorax. '
Thus, the bones which, in a manner, give a foun-
dation to those of the anterior 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 apparatus of
the ornithorynchus paradoxus, since the whole frame
and organs of this animal imply, that it is intermediate
between mammalia and birds; and it is placed in the
list of edentata. We introduce it here, as another
instance of the changes which the bones of the
shoulder undergo with every new office, and in cor-
respondence with the motions, of the extremity;


OF THE BONES OF THE SHOULDER.
57
whether it be to support the weight in running, or to
give freedom to the arm, or to provide for flying, or
D
.
In
GUNA
a
B.
for performing equally the act of creeping and of
swimming.'
Unprofitable as the enquiry may seem, there is no
other way by which the geologist can distinguish the
genera of those oviparous reptiles, which he finds
imbedded in the secondary strata, than by studying
the minute processes and varying characters of these
bones, in the different classes of animals. In the
ichthyosaurus, and plesiosaurus, the inhabitants of a
former world, and now extinct, we perceive a consid-
erable deviation from the perfection of the bones of the
arın and hand, compared with the frog and tortoise:
but if strength is the object, there is a greater degree
of perfection in the bones of the shoulder. The expla
nation of this is, that the ribs and sterno-costal arch
es, constituting the thorax are more perfect, than in
A. Clavicle. B. Coracoid bone. c. A new bone, introduced into
the apparatus, which articulates with the coracoid bone, and lies
interior to the clavicle. D. Scapula. E. Acromion Scapulæ.


58
COMPARATIVE ANATOMY
the chelonian and batrachian orders; and the bones
of the shoulder are therefore external, and resemble
those of the crocodile ; yet the ribs are so weak as to
be incapable of sustaining the powerful action of the
anterior extremities; accordingly, the bones, which
by a kind of licence we continue to call clavicle,
omoplate or scapula, and coracoid, though strangely
deviating from the original form and connections,
constitute a texture of considerable strength, which
perfects the anterior part of the trunk, and gives
attachment and lodgment 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. Why is the apparatus of
respiration so totally changed in these classes of ani-
mals? They are cold blooded animals; they require
to respire less frequently than other creatures, and
they remain long under water. I conceive that the
peculiarity in their mode of respiration corresponds
with this property. Hence their vesicular lungs,
their mode of swallowing the air, instead of inhaling
it; and hence, especially, their power of compressing
the body and expelling the air; it is this, I imagine,
which enables them to go under the water and crawl
upon the bottom ; without this, that is to say, had they
possessed the lungs of warm blooded animals, which
are compressible only in a slight degree, their capa-
city 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 compressed, and the specific weight
diminished. The facility which the absence of ribs
gives, in the batrachian order, and the extreme
weakness and pliancy of these bones in the saurians,


OF THE MOLE AND THE BAT

he
TA
There can be no greater contrast to these bones
than is presented in the skeleton of the bat. In
ASSES
which their hands are assisting, in throwing aside the earth. The
conformation of the head in shape and strength of bones, and the
new adjustment of a muscle, which is cutaneous in other animals
(the Platisma Myoides) to the motions of the head, are among the
most curious changes of common parts to new officos.


62
ANT-EATER.
that animal the bones are light and delicate; and
whilst they are all marvellously extended, the pha-
langes of the fingers are elongated, so as hardly to be
recognized, obviously for the purpose of sustaining a
membraneous web, and to form a wing. ...
Contemplating this extraordinary application of
the bones of the extremity, and comparing them
with those in the wing of a bird, we might say, that
this is an awkward attempt a failure. But before
giving expression to such an opinion, we must un-
derstand the objects required in this construction.-
It is not a wing intended merely for flight, but one
which, while it raises the animal, is capable of re-
ceiving a new sensation, or sensations in that exqui-
site degree, so ás almost to constitute a new sense.
On the fine web of the bat's wing, nerves are distri-
buted, which enable it to avoid objects in its flight,
during the obscurity of night, when both eyes and
ears fail. Could the wing of a bird, covered with
feathers, do this? Here then we have another ex-
ample of the necessity of taking every circumstance
into consideration before we presume to criticise the
ways of nature. It is a lesson of humility.*
In the next page we have a sketch of the arm
bones of the Ant-eater, to shew once more the corres-
pondence in the whole extremity. We observe these
extraordinary spines of the humerus marking the
power of the muscles which are attached to it; for
as I have said before, whether we examine the hu-
man body, or the comparative forms of the bones,
the distinctness of the spines and processes declares
the strength of the muscles. It is particularly pleas-
* Besides the adaptation of the bat for flight, through a new ad-
ustment of the bones of the arm, this animal has cells under its skin;
but I know not how far I am authorized to say that they are analo-
gous to the air-cells of birds, or that they are for the purpose of mak-
ing the bat specifically lighter. They extend over the breast, and
under the axillæ in some bats; and they are filled by an orifice which
communicates with the pharynx.
f Tamandua, from South America.


64
STRUCTURE OF BIRDS.
is an example of the relation of the particular parts
of the skeleton to one another; and were it our busi-
ness, it would be easy to shew, that as there is a cor-
respondence 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 expecta-
tion of finding a projecting muzzle unarmed with
teeth, and a long tongue provided with a glutinous
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 projecting acromion scapulæ, and a remarkable
process of the humerus, that there is a provision for
the rotation of the arm, which implies burrowing.
But the apparatus seems by no means so perfect as in
the mole, implying that it digs in a softer soil than
that animal, whilst the possession of gnawing teeth
indicates that it lives on roots. .
In Birds there is altogether a new condition of
parts, as there is a new element to contend with.
The very peculiar form and structure of their skele-
ton may be thus accounted for. First, it is necessary
that birds, as they are buoyed in the air, be specifi-
cally lighter. 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 attachment.
Both these objects are attained by a modification of
the apparatus of breathing. The lungs are highly
vascular and spongy, but they are not distended with
air. The air is drawn through their substance 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
chapter, of the weight of the body being a necessary


STRUCTURE OF BIRDS.
65
concomitant of muscular strength, we see why birds,
oy reason of their lightness, as well as by the confor-
mation of their skeleton, walk badly. And, on the
other hand, in observing how this lightness is adapt-
ed 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-bone
of birds extends the whole length of the body; and
owing to this extension, a lesser degree of motion
suffices to respiration. So that 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 vertebræ of the
back; a proof, if any were now necessary, that the
whole system of bones conforms to that of the extrem-
ities, the firmer texture of the bones of the trunk,
being a part of the provision for the attachment of the
muscles of the wings.t
The vertebræ 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. We cannot but admire, therefore,
the composition of the neck and head, and how the
extension of the vertebræ, and the length and plia-
bility of the neck, whilst they give to the bill the
office of a hand, become a substitution for the loss of
* It is interesting to notice the relations of great functions in the
animal economy. "Birds are oviparous, because they never could
have risen on the wing had they been viviparous; if the full stomach
of a carnivorous bird retard its flight, we perceive that it could not
have carried its young. The light body, the quill-feathers, the bill,
and the laying of eggs, are all necessarily connected.
f The ostrich and cassowary, which are rather runners than fliers,
have the spine loose.
6*


68
ANATOMY OF
reached double the whole length of the animal, and
the conjecture is, that upon it was extended a mem-
brane, resembling that of the Draco fimbriatus. In
the imperfect specimens which we have, we cannot
discover in the height of the pelvis, the strength of
the vertebræ of the back, or the expansion of the
sternum, a provision for the attachment of muscles
commensurate with the extent of the supposed wing.
The humerus, and the bones, which we presume are
the scapula and coracoid, bear some correspondence
to the extent of the wing ; but the extraordinary
circumstance of all, is the size and strength of the
bones of the jaw and vertebræ of the neck, compared
with the smallness of the body, and the extreme deli,
cacy of the ribs; which make it, altogether, the
thing most incomprehensible in nature. ; .
OF THE RADIUS AND ULNA.
- The easy motion of the hand, we might imagine to
be in the hand itself; but, on the contrary, the move-
ments which appear to belong to it, are divided
among all the bones of the extremity.*
The head of the humerus is rotatory on the sca-
pula, as when making the guards in fencing; but
the easier and finer rolling of the wrist is accom-
plished by the motion of the radius on the ulna.
The ulna has a hooked process, the olecranon,
which catches round the lower end of the humerus
or arm bone, (this articulating portion is called tro-
chlea), and forms with it a hinge joint. The radius,
again, has a small, neat, round head, which is bound
to the ulna by ligaments, as a spindle is held in the
bush. This bone turns on its axis and, as it turns,
* In the sketch in the next page, 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.


THE FORE-ARM.
69
carries the hand with it, because the hand is strictly
attached to its lower head alone. This rolling, is
what is termed pronation and supination.
ne
Such a motion would be useless, and a source of
weakness in an animal that had a solid hoof. Ac-
cordingly, in the horse, these bones are united
together and consolidated in the positon of pronation.


70
ANATOMY OF
It is interesting to find that by studying the pro-
cesses of the bones, than which nothing, at first
sight, appears more inconsequent, we are learning the
characters of a language which shall enable us to
read monuments of the highest interest ;-the records
of the creation, which give an account of the revo-
lutions of the earth itself..
If a geologist should find the nearer head of the
radius, and see in the extremity of it a smooth de-
pression, where it bears against the humerus, and
observe the polished circle 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. Claws may belong to two species of animals ;
the feline, which is possessed of sharp carnivorous
teeth, or to animals without teeth. If he should
find the lower extremity of this same bone, and ob-
serve on it spines and grooves for the distinct tendons
which disperse to the phalanges, he would conclude
that there must have been moveable claws that it
belonged to a carnivorous animal; and he would
seek for canine teeth of a corresponding size.
OF THE WRIST AND HAND.
In the human hand, the bones of the wrist (car-
pus) 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 to-
wards the fingers are the metacarpal bones, which
diverge at their further extremities, and give support
to the bones of the fingers. The thumb has no'me-
tacarpal bone, and is directly articulated with the
carpus or wrist. There are thus in the hand twenty-
nine bones, from the mechanism of which, result
strength, mobility, and elasticity. .
Lovers of system (I do not use the term disparag-
ingly) delight to trace the gradual substraction of the


THE WRIST AND HAND.
71
bones of the hand. Thus, looking to the hand of
man, they see the thumb fully formed-in the simiæ
they find it exceedingly small; in one of them, the
spider-monkey, it has disappeared, and the four fin-
gers are sufficient, with hardly the rudiments of a
thumb. In some of the tardigrade animals, there
are only three metacarpal bones with their fingers.
In the horse, the cannon bone may be shewn to
consist of two metacarpal 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 a
variety, most curiously adapting, as I have often to
repeat, the same system of parts to every necessary
purpose. ..
. In a comparative view of these bones, we are led
more particularly to notice the foot of the horse ; it
is universally admitted to be of a beautiful design,
and calculated for strength and elasticity, and espe-
cially provided against concussion. .
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 new modelled; but the metacarpal
bones and phalanges of the toes are totally changed,
and can hardly be recognized. 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 diminish gra-
dually, and they are held by an elastic ligamentous,
attachment to the sides of the cannon bone. !
I have some hesitation in admitting the correct.
ness of the opinion of veterinary surgeons of this cu-
rious piece of mechanism. They imagine that these


72
ACTION OF THE SPLINT BONES.
moveable splint bones, by playing up and down,
as the foot is alternately raised and pressed to the
ground, bestow elasticity and prevent concussion.-
The fact certainly is, that by over action this part be-
comes inflamed, and the extremities are preternatu-
rally joined by bone to the greater metacarpal or can-
non bone; and that this, which is called a splint,
is a cause of iameness. .
- 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
inust principally depend, it will not escape observa-
tion, that in the bent position of the knee, the exten-
sor tendons have very little power, owing to their


IN THE HORSE'S LEG.
73
· running so near 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 de-
scend, 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 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 condition of the joint when the foot is eleva-
ted, and that then, the bone must descend. If it be
depressed when the foot is raised, and have a power of
recoiling (which it certainly has) it must aid in throw-
ing out the leg into the straight position and assist the
extensor muscles. 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 extension 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 69, 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. But the foot itself de-
serves our attention. The horse, a native of exten-
sive plains and steppes, is perfect in his structure, as
adapted 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 that part an object of great inter-


74
OF THE HORSE'S FOOT.
est : and I have it from the excellent professor of ve.
terinary surgery to say, that he has never demon-
strated the anatomy of the horse's foot without find-
ing something new to admire. .
· The weight and power of the animal require that
he should have a foot in which strength and elasti-
city are combined. The elasticity is essentially ne-
cessary to prevent percussion in striking the ground;
and it is attained here, through the united effect of
the oblique position of the bones of the leg and foot
-the yielding nature of the suspending ligament,
and the expansibility of the crust or hoof. So much
depends on the position of the pastern bones and
coffin bone, that judging by the length of these and
their obliquity, it is possible to say whether a horse
goes easily, without mounting it. When the hoof
is raised, it is smaller in its diameter, and the sole is
concave ; but when it bears on the ground it expands,
the sole descends so as to become flatter; and this
expansion of the hoof laterally, is necessary to the
play of the whole structure of the foot. Hence it
happens that if the shoe be nailed in such a manner
as to prevent the hoof expanding, the whole interior
contrivance for mobility and elasticity is lost. The
foot, in trotting, comes down solid, it consequently
suffers percussion; and from the injury, it becomes
inflamed and hot. From this inflammation is gene-
rated a variety of diseases, which at length destroy
all the beautiful provision of the horse's foot for free
and elastic motion.
This subject is of such general interest, that I may
venture, on a little more detail. The elastic or
suspending ligament spoken of above, passes down
from the back of the cannon bone, along all the
bones, to the lowest, the coffin bone; it yields, and
allows these bones to bend. Behind the ligament
the great tendons run, and the most prolonged of
these, that of the perforans muscle, is principally
inserted into the coffin bone, having at the same time


176
FOOT OF RUMINANTS.
ant, 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.
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 vacuum or suction, as it is withdrawn; while
the split and conical shaped hoof expands in sinking,
and is easily extricated.'
In the chamois and other species of the deer 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 elasticity. 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,” 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 pro-
jecting 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 prin-
ciple 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


ELEPHANT AND CAMEL.
77
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 bones of the
foot. In the foot of the living animal 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 car-
pus, metacarpus, and phalanges of the toes; and
these bones have a very different use from what we
have hitherto noticed. They are not connected with
a moveable radius, and have no individual motion, as
in the carnivorous animal--they merely serve to ex-
pand the foot, the base of the column, and to give it
a certain elasticity.
In page 53 I have noticed the bones of the foot
of the camel in contrast with those of the elephant.
The camel's foot having no such disproportioned
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 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 toes;
and let us 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. But
we must preface 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,
7*


78
MECHANISM OF
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 movement ; 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 cor-
respondence 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 protect 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 lateral to the
penultimate bone, and is so articulated with it, that
an elastic 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
* The pads in the bottom of the lion's foot cover these bones, or
rather, we should 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 a manner so
peculiar in relation to the penultimate, being drawn back by the
elastic ligament (A) beyond the centre of motion of the joint, that the
flexor tendon (B) acting upon it, forces the nearer end, and the cush-
ion of the toe to the ground. But when 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; so that the action
of the flexor tendon can now draw forward the last bone-thus
unsheathing and uncovering the claw, and preparing it to hold or to
tear.


THE LION S CLAW.

.
.
B
claw is thus retracted into a sheath. But when the
- tiger makes his spring, the claws are uncased by the
action of the flexor tendons; and they are so sharp
and strong in 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 observation of President Jef-
ferson on the Megalonix. Haying found a bone,
which by its articulating surface and general form,
he recognised to be one of the bones of the phalanx
of an animal of great size, he thought he could dis-
cover that it had carried a claw; and from this cir


84'
BONES IN THE CETACEA.
We have sketched here, the bones of the morse,
or walrus, and they are remarkably complete, if we
consider the appearance of the feet in the living'ani-
mal. The bones are here accommodated to an in-
strument for swimming; for these animals live in
the water, and come to land only to suckle their
young, or to bask in the sun; and they, are the most
unwieldy and helpless, out of the water, of all ani-
mals which breathe.
In the Cetacea, we have mammalia without hind
feet. The scapula is large, the humerus very short,
and the bones of the fore-arm and hand flattened
and confined in membranes which convert them into
a fin. They live in the water, but must rise to
breathe.
I need not say that in the dolphin we recognize
the bones of the anterior extremity, only a little fur-
ther removed from the forms which we have hitherto
been contemplating. The seal and morse raise them-
selves out of the water and lie on the rocks; the dif-
ferent species of the dolphin continue always in the
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.
The last examples I select, shall be from the an-
cient world.*
* The figure to the left is the anterior extremity of the Plesiosau-
rus; to the right that of the Ichthyosaurus. In these paddles we
see the intermediate changes from the foot of land animals to the fin
of the fish. The walrus, dolphin, turtle, plesiosaurus, ichthyosaurus
where we no longer find the phalanges or attempt to count the
bones. They become irregular polygons or trapezoids—less like
the phalanges than the radii of the fins of a fish. In fishes the ante-
rior extremnity is recognized in the thoracic fin; and we may even
discover the prototypes of the scapula and the bones of the arm. I
know not what the naturalist, who likes to note the gradual decrease
of the elementary parts, makes of these hundred bones of the pad-
dle or of the fin; where there is an increase of the number, whilst,
relatively speaking, there is a defect of form and motion, of the parts.


IN THE ICHTHYOSAURUS.
85
.
: These figures are taken from specimens in the Col-
lege of Surgeons, of fossil animals of singular struc-
ture, 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 car.
pus and fingers. No fault is to be found with the
construction of these instruments; they are suited to
their offices, and no bone is superfluous, or misplaced,
or imperfect. The ichthyosaurus and plesiosaurus
(the animals which offer these specimens) inhabited
the sea ; the remains are found low in the lias de-
posit ; great changes have been wrought on the land


86
PECULIARITIES IN THE HAND.
and on the deep since they existed; and the race of
animals, the structure of whose extremities we have
been engaged in examining, were not then in being.,
When we discover the same series of bones in the
animals of the old world, 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 thousand 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 extremity,
which suit them to every possible variety of use.
After a little attention to the form of the human
hand, I shall take up another division of my subject.
The motions of the fingers do not merely result
from the action of the large muscles which lie on
the fore-arm-these are for the more powerful actions;
but in the palm of the hand, and between the meta-
carpal bones, there are small muscles (Lumbricales
and Interossei), which perform the finer motions, ex-
panding the fingers and moving them in every direc-
tion, with great quickness and delicacy.' These are
the organs which give the hand the power of spin-
ning, weaving, engraving; and as they produce the
quick motions of the musician's fingers, they are
called by the anatomist fidicinales. Attention to our
most common actions will shew us, how the division
into fingers, by combining motion with the sense of
touch, adapts the hand to grasp, to feel, and to com-
pare. We shall presently see how well the points of
the fingers are provided for feeling : as the joints and
numerous muscles of the hand are adapted for
various, distinct, or separate motions.
In this sketch we have the bones of the paw of the
adult Chimpanzee, from Borneo; and the remarka-


PECULIARITIES IN THE HAND.
ble peculiarity is the smallness of the thumb; it ex-
tends 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 the
fingers. Without the fleshy ball of the thumb, the
power of the fingers would avail nothing ; and, ac-
cordingly, 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,t
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 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 purposes, 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
* The monkey has no separate flexor longus of the thumb. Vicq.
Azyr.
*Manus parva, majori adjutrix.” Albinus.


PECULIARITIES IN THE HAND.
and on the deep since they existed; and the race of
animals, the structure of whose extremities we have
been engaged in examining, were not then in being.
When we discover the same series of bones in the
animals of the old world, 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 thousand 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 extremity,
which suit them to every possible variety of use.
After a little attention to the form of the human
hand, I shall take up another division of my subject.
The motions of the fingers do not merely result
from the action of the large muscles which lie on
the fore-arm--these are for the more powerful actions;
but in the palm of the hand, and between the meta-
carpal bones, there are small muscles (Lumbricales
and Interossei), which perform the finer motions, ex-
panding the fingers and moving them in every direc-
tion, with great quickness and delicacy.' These are
the organs which give the hand the power of spin-
ning, weaving, engraving; and as they produce the
quick motions of the musician's fingers, they are
called by the anatomist fidicinales. Attention to our
most common actions will shew us, how the division
into fingers, by combining motion with the sense of
touch, adapts the hand to grasp, to feel, and to com-
pare. We shall presently see how well the points of
the fingers are provided for feeling : as the joints and
numerous muscles of the hand are adapted for
various, distinct, or separate motions.
In this sketch we have the bones of the paw of the
adult Chimpanzee, from Borneo; and the remarka-


CHAPTER IV.
OF THE MUSCLES.
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 concentrating 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 con-
sent to the simplest action ; but this gives an imper-
fect 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 of a cor-
responding 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 pro-
perty of the muscles ;, and then of the mechanical
contrivances, in their form and application. In all
8*


90
OF THE MUSCLES OF
that regards the muscles, we see the most bountiful
supply of power commensurate 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 contraction,
perform their office with comparative ease. A sta-
tionary condition of the limb results from a balanced
but regulated action of all the muscles ; which con-
dition 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 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 toʻrelax; and the will influences
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 con.
vulsed, or, as the physicians term it, in clonic 'spasms,
The similitude of the two sawyers, mentioned by
Paley, gives but an imperfect 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 has not given up all effort, like a
loose rope, but it is controlled in its yielding, with as
fine a sense of 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 innume-
rable muscles put into activity, but as many are


THE ARM AND HAND.
91
thrown out of action, and the condition of these
classes is totally opposite to each other, under the
same act of volition.
By such considerations, we are prepared to admire
the faculty which shall combine a hundred muscles
so as to produce a change of posture or action of the
body; and we now perceive that the power taken
from one class of our muscles, may be considered as
if it were bestowed on the other; so that the pro
perty 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 abun.
dantly, 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 direc-
tion,-thus, A. being the tendinous origin of a muscle,
and B. the tendinous insertion, the fleshy fibres run
obliquely between these two tendons.
A
ht
BE
The fibre acting thus obliquely løses power, but
gains the property of pulling what is attached to its
further extremity through a greater space, while it
contracts. This mechanical arrangement is intelli-
gible on the law, that velocity of motion through
space, is equal to power or weight. Here in the
muscle, there is a resignation of power to obtain ve-
locity of motion.
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


OF THE MUSCLES OF
straight line to the toes or tips of the fingers: but
by being laced down in sheaths, they inove 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 velo-
city 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
the 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 impulse from ano-
ther, 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 ex-
hausted in changing the body from a state of rest to
that of motion—but being in motion when it receives
the second blow, the whole power is bestowed on the
acceleration 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 im-
pulse is originally given. The slight blow given to
à boy's hoop is sufficient to keep it running; 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


• THE ARM AND HAND.
93
muscle near the shoulder, * c. acts upon the humerus,
B. in raising the extended 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.
ANNO
HP
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 liam-
mer; for in descending through a large space, it ac-
cumulates 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 produced
which the combined power of all the muscles, with-
out this mechanical distribution of force, could not
accomplish.' This is, in truth, similar to the opera-
tion of the fly wheel, by which the gradual motion of
an engine is accumulated 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 me-
chanism 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 proportion to
its weight, it is difficult to be put in motion. The
* 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.


COMPARATIVE ANATOMY
test of his master's perfection as a 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. The
flexors, extensors, pronators, and supinators are, in
the brute, exactly in the same place, and bear all the
relations which the student of anatonly is taught to
observe with so much interest in the human arm.
This example is sufficient to show how accurately
the comparative anatomy of the muscles conforms to
that of the bones ; and that in proportion 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 established in the animal system. . .
There is one circumstance more which should not
be omitted in the comparative anatomy of these mus-
cles, as it exhibits another instance of conformity in
their structure, to the offices which they have to per-
form. We have just stated that the power of con-
traction 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 perpetu-
ating the circulation of the blood, which is the source
of all vital power.
In the lémur tardigradus it has been observed that
the axillary and femoral arteries, the great arteries of
the anterior and posterior extremities, have this pecu-


OF THE MUSCLES OF THE ARM.
97.
liarity--that the trunk is subdivided into a number
of equal-sized cylinders, which again unite to form a
single trunk previous to the distribution of its branches
to the muscles.* It has been argued that this pecu-
liarity, as it produces a retardation of the blood, is
adapted to long continued action in the muscles. 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 tenacity of their hold. The extremities, are
long and the muscles powerful, either to sustain the
animal by grasping the branches of trees, or for dig-
ging; but surely the strength of the muscles cannot ·
be produced by retardation of the circulation, on the
principle, universally admitted, that the expenditure
of arterial blood is in proportion to the vital force
employed.
Were the arteries of the living body. like rigid
tubes, and the laws of the circulation the same as
those of hydraulics, such might be the conclusion.
But it is impossible to suppose that the circulation of
the blood could 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; both
the dilatability and the contractility of arteries are
subject to the influences of the living principle.
When, therefore, the artery of a limb is divided into
four or five vessels, the result is a greater capacity of
dilatation, a greater power of contraction; and these .
being vital operations, are subject to be influenced
and adjusted according to the necessity for the in-
crease or diminution of the circulation. .
If such a peculiarity in the form of the vessels in
he extremities of these animals, retards the blood,
t can only be during repose ; for, on excitement, so
far from retarding, it must bestow remarkable power
of acceleration. I conclude, therefore, that this va-
* There is some doubt as to the reunion of the vessels.


98
SUPERIORITY OF THE
riety of distribution 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 continued action and rigidity.
We have seen in the preceding chapter the same
organ, which moves at one time as slowly as the
hand of a watch, at another moves with extreme
rapidity : consequently, we cannot admit the infer-
ence that the tortuous and subdivided artery is a pro-
vision for languid motions.
In speaking of the arteries which go to the hand,
it may be expected that we should touch on a sub-
ject, which has been formerly a good deal discussed,
whether the properties of the right hand, in compa-
rison with those of the left, depend on the course of
the arteries to it. 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 common 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 distinc-
tion 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 pro-
perties. The developement of the organs of action
and motion is greatest upon the right side, as may at
any time be ascertained by measurement, or the tes-
timony of the tailor or shoemaker; certainly, this


RIGHT HAND OVER THE LEFT
99
superiority may be said to result from the more fre-
quent exertion of the right hand; but the pecu-
liarity 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 performed 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 it, 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
peculiar 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
auger, is not arbitrary, but is related to a natura, en-
dowment of the body. He who is left handed is
most sensible to the advantages of this adaptation,
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 pur-
pose : and the property does not depend on the pecu-
liar distribution of the arteries of the arm but the
preference is given to the right foot, as well as to the
right hand.


SUBSTITUTES FOR THE HAND.
101
free for such efforts as enable them* to seize their
food. The apparatus by which they attach them-
selves 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.
In the cuttle-fish we see a modification of this
apparatus : the suckers are on the extremities of their
processes or arms, and become instruments of prehen-
sion and of locomotion. They are capable of turning
in all directions, either to fix the animal or to drag it
from place to place. In the Indian Seas, these crea-
tures become truly terrific from the length of their
arms, which extend to eight or nine fathoms, and
from the firmness with which they cling.
Dr. Shaw tells us, that on throwing a fish of 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 con-
tained some gallons of water. .
There is another fish, which from its name we
should expect to perform strange antics ; it is called
harlequin angler.t It appearance is grotesque and
singular ; the pectoral fins resemble short arms, and
are palmated at their tips. M. Renau, in his histo-
* In the Mollusca and Zoophytes we find many instances of the
animal holding on against the force of tide or current. The Actiniæ
fix themselves to rocks and shells; and some, as the sea carnation,
hang suspended from the lower surface of projecting rocks, resem-
bling 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.
† Lophius Histrio, from a Greek word that has reference to the
process which floats from the head, like a streamer or pennant.
I These fins have two bones in them like the radius and ulna; but
Cuvier says, that they are more strictly bones of the carpus.
9*


102
SUBSTITUTES FOR THE HAND.
ry 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 cir-
cumstance 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 inclines me to believe it ; and
its habits require such a provision. In this genus,
the operculum 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. The cavities in which the branchiæ 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 gills into pouches,
capable of containing water, and of permitting the
function of the branchiæ to proceed when the water is
retired; that is, when it lies in mud, or shallow
pools ; for in such situations does the lophius find its
food, where 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, without
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 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
palpa and tentacula of insects and crustacea. The
.* The spines of the Echinus are moveable; they assist in progres-
sion. 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.


SUBSTITUTES FOR THE HAND.
103
fishing lines of the lophius piscatorius are examples of
these processes : and Pliny relates that this frog-like
fish, hiding in the mud, leaves the extremities of
these filaments visible; which, from their resem-
blance 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 chætodon (bandouliere à bec)
squirts water at flies as they pass and brings them
down. The scicna jaculatrix, according to Pallas,
has a similar power; and the sparus insidiator catch-
es 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 blepharis, 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 mus-
cular 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 aris-
ing from the brain, and are distributed within and
around the head ; and, pursuing the subject by the
aid of comparative anatomy, I found that a nerve cor-
responding 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 becomes 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 crustacea and insects. It is the same nerve
which supplies the tongue, and is the organ of its ex-
quisite 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


CHAPTER VI.
THE ARGUMENT PURSUED FROM THE COMPARATIVE
ANATOMY.
So far as we have hitherto proceeded, by examin-
ing objects in comparative anatomy which from their
magnitude can not 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 uniformity 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 that every change has been for a pur-
purpose, and every part has had its just relation.
We have witnessed all the varieties moulded to such
a perfect accommodation, and the alterations pro-
duced by such minute degrees, that all notion of ex-
ternal and accidental agency must be rejected.
We might carry our demonstration downward
through the lower classes of animals; for example,
we might trace the feet of insects from their most
perfect or complex state, till they disappear; or, ob-
serving the changes in another direction, we might
follow out the same parts from the smallest begin-
ning to the most perfect condition 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


106
THEORY OF
bristles standing out from distinct mammillary pro-
cesses, which are furnished with appropriate 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 anatomy.
Nay, it is most 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 ob-
ject, we view the delicate and curiously adapted in-
struments of insects, we must perceive that it would
be easy to trace almost every part through a succes-
sion of modifications. 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 characterized
by four wings. Proceed to examine a third example,
and we shall discover that this anterior wing is larger
and more perfect than the posterior : the fourth spe-
çimen 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 nature,
but new forms of the body; new appendages re-
quired for a different poišing 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 upon us, how
are those varieties to be explained?
The curious adaptation of a member to different
offices and to different conditions of the animal has


ELEMENTAL PARTS.
107
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 assimi.
late matter by the 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 illustrate by
the analogy of the building materials of a house.
If these materials, they say, are exhausted in the or-
namental parts of the portico and vestibule, 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 æra! They speak of the
“ elective affinities of organs,” “the balancing of or-
gans," "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 af-
firm, that this surpasses all former systems as a
means of discovery. Now, the perfection or aggran-
dizement of any one organ of an animal is not at-
tended with the curtailment or proportional deficien-
cy of any other. Like ourselves, perhaps, the sup-
porters of this theory dwell too much upon the bones;
but even in them, we shall show that the system is
untenable. In the mean time, we may ask, do ad-
ditional parts connected with the stomach, making it
highly complex, as in ruminating animals, shorten'
the intestinal canal, or make its form simpler ? On
the contrary, is not a complex stomach necessarily
connected with a long and complicated intestine !
Does a complex intestinal canal throughout all its


108
THEORY OF
course render imperfect the solid viscera which are
in juxtaposition to it? Is there any defect in them,
because the organs of digestion are perfect, or com-
plicated ? 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, re-
spiration and sensation, bear ever a proportional in-
crease? Is there any instance of an improvement in
one organ thrusting another out of its place, or di-
minishing its volume?
Now, as to the osseous system, were we to follow
these theorists into the very stronghold of their posi-
tion, the bones of the skull, where the real intricacy
of the parts allows them some scope for their ingenu-
ity, 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 office ;
that they have an important share in the act of re-
spiration, 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; and which, yet, shall
leave us in the contemplation of this class of ani-
mals deficient in thirty-two ribs, without pointing out
where they are to be found, or how their elements are
uilt up in other structures ? If, on the contrary,
we take the principle that parts are formed or with-
drawn, with a never-failing relation to the function
which is to be performed, we see that no sooner are
the compages of the chest removed, and the should-
er thus deprived of support, than the bones to which


110
THEORY OF
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 office of the chain of four
bones which belong 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;—and if it be said that the os quadratum
is the missing incus, why should not we find in the
oviparous reptiles, where there is a columella in the
ear, an os quadratum in the jaw?
From this mode of inquiry, we find that the sense
of hearing is enjoyed in an exquisite degree in birds :
that the organ of the sense is not imperfect, but is
adapted to a new construction, and a varied appara-
tus-suited to the condition of the bird : and that
there is no accidental dislocation or substitution of
something less perfect than what we find in other
classes of animals.
If we now look to the structure of the mandible of
the bird, we shall find as curious, though a some-
what grosser example of mechanical relation. The
bill of the bird, in some degree, pertains to our sub-
ject, as it is the organ of prehension and of touch.
It is withal'a fly trap-hence, its motions must be
rapid : and the velocity 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


SURROUNDING INFLUENCÉ.
113
.
sun, or as the roots shoot to the appropriate soil, so
do the exterior organs of animals grow and adapt
themselves. We shall presently find that an opinion
has prevailed that the organization of animals deter-
mines their propensities; but the philosophers, of
whom we are now speaking, imagine 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 in-
stances of the production of new organs by the
union of individuals belonging to different species.
Nor is there any foundation in observation for the
opinion that a new species may be formed by the
union of individuals of different 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 be-
fore that time; that is, previous to the present condition
of the world. But, on subjects of this nature, we must
argue from what we know, and from what we see.
We do perceive surprising changes in the con-
formation of animals; some of them are very fami-
liar to us; but all show a foreknowledge and a pro-
spective 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
conditions of existence in the body. Hardly two
creatures can be less alike than an infant and a man.
The whole fotal 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 demonstrate. 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 proportions of
the body to the state of perfect manhood, Few,
however, are aware that the fætus has a life adapted
10*


114
THESE THEORIES INCORRECT.
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 sim-
ply, 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 constructed
before the flood-gates, which are to 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 recognize it simple, at first, and gra-
dually 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 me
tamorphosis 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 distribu-
tion of its nervous system, But if, anticipating its
metamorphosis, we dissect the same larva immedi,
ately before the change, we shall find a new appara.
tus in progress towards perfection ; the muscles of its
many feet are seen decaying; the nerves to each


THESE THEORIES INCORRECT.
115
muscle are wasting; a new arrangement of muscles,
with new points of attachment, directed to the wings
instead of the feet, is now visible; and a new distri-
bution of nerves is distinctly to be traced, accommo-
dated 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 externally,
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 texture of nervous
filaments, which is laid intermediate between the in-
strument and the very centre of life and motion ; and,
finally, as we shall discover from what follows, new
sources of activity must be created in relation to the
new organ, otherwise the part will hang a useless
appendage. :
1. It must now be apparent that nothing less than the
Power, which originally created, is equal to the effect-
ing of those changes. on animals, which are to adapt
them to their conditions : that their organization is
- predetermined, and not consequent on the condition of
the earth or the surrounding elements. Neither can
à 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 succes-
sive changes in the inorganic matter of the globe-the
condition of the water, atmosphere, and temperature
brings with it only an accumulation of difficulties.


CHAPTER VII.
OF SENSIBILITY AND TOUCH.
We find every organ of sense, with the exception
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, hyæna, 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 ani-
mals. 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 hand
there is a double sense exercised; we must not only
feel the contact of the object, but we must be sen-
sible 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,


COMPARED WITH THE DEEPER PARTS.
119
and kind of sensibility with the skin, so far from sery-
ing any useful purpose, this sensibility would have
been a source of inconvenience and continual pain in
the common exercise of the frame.
The reason why surgeons more than physicians
have advanced the study of physiology, may be, that
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 mis-
calculated what was necessary to the correct perform-
ance of his operation, but because the patient, bear-
ing courageously the deeper incisions, cannot sustain
the renewed cutting of the skin, without giving toker
of severe pain.'
The fact of the exquisite sensibility of the surface,
in comparison with the deeper 'parts, being thus as-
certained 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 provi-
sion, 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
i nquiry, 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


120
SENSIBILITY TO PAIN.
-
these instances of insensibility, 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 unwilling to
terminate the investigation here. ,
In the first place, we must perceive that if a sensi-
bility similar to that of the skin had been given to
these internal parts, it must have remained unexer-
cised. · Had they been made sensible 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 in-
quire whether any injury can reach these internal
parts without the sensibility of the skin being excited.
Now, of this there can be no doubt, for they are sub-
ject 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 pro-
vision to guide us in the safe exercise of the limbs;
and notwithstanding what has been apparently de-
monstrated of the insensibility of these internal parts,
they must possess an appropriate sensibility, or it
would imply an imperfection.
• With these reflections, we recur to experiment
and we find that the parts, which are insensible to
pricking, cutting, and burning, are actually sensible
to concussion, to stretching, or laceration.
How consistent, then, and beautiful is the distribu-
tion of this quality of life! The sensibility 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


122
SENSIBILITY TO HEAT.
“ the parts that press upon the bed ; from which come
“ local irritation, then fever and mortification and
6 death. -
« Thus you perceive that the natural sensibility of
“the skin, without disturbing your train of thought,
“induces you to shift the body so as to permit the free
“circulation of the blood in the minute vessels; and
“that when this sensibility is wanting, the utmost
"attention of friends and the watchfulness of the
“nurse are but a poor substitute for this protection
“which nature is continually affording. If you suf-
“fer 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 ac-
“tive 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 different
endowment from that of touch. This sensibility to
the varietįes 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 uni-
form temperature, it would have been, in them, a
quality altogether, superfluous. But as we are sur-
rounded 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 possession
of this peculiar sensibility on the surface affords
another proof of there having been a foreknow-
ledge of our condition. We might, indeed, take
our former example in evidence of what must befal
through the want of this sensibility-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


SENSIBILITY OF HEAT.
123
the fire and deliberately replaced it, not being con-
scious 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 aggra-
vate nor heat in any degree assuage.* Sensibility
to heat is a safeguard in as much as it is capable of
becoming 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 physical in-
fluence. Heat is uniform in its effect on matter; but
the sensation varies as it is given or abstracted from
the living body. Cold and heat are distinct sensa-
tions; 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
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
shew how very different sensibility is, in reality, from
what is suggested by first experience, and how admi-
rably it is varied and accommodated to the functions,
we shall add one other fact. The brain is insensible
--that part of the brain, which if disturbed or dis-
eased, 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 interrupting
the patient in the sentence that he is uttering, is a
surprising circumstance! From this fact Physiolo-
gists formerly inferred that the surgeon had not
* There are certain morbid conditions of sensation when cold
bodies feel intensely hot.—Dr. Abercrombie's Inquiry into the Intel-
lectual powers.


124
SENSIBILITY OF THE EYE.
reached the more important organ of the brain. But
that opinion arose from the notion prevailing that a
nerve must necessarily be sensible. Whereas, when
we consider that the different parts of the nervous sys-
tem have totally distinct endowments, and that there
are nerves, as I have elsewhere shewn, insensible to
touch and incapable of giving pain, though exquisite-
ly alive to their proper office, we have no just reason
to conclude that the brain should be sensible, or
exhibit the property 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 provi-
sion.*
To satisfy my reader on this interesting subject, 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 atmosphere, and to the contact of which
the common skin is quite insensible. The mechani-
cal, 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 exquisite sensibility to direct it--not that
kind of sensibility which enables the eye to receive
* See the Sensibility of the Retina, Appendix.


SENSIBILITY OF THE EYE.'
125
the impressions of light—but a property more resem-
bling the tenderness of the skin, yet happily adapted,
by its fineness, to the condition of the organ. '
A nerve, possessed of a quality totally different
from that of the optic nerve, extends over all the ex-
terior surfaces of the eye, and gives to those surfaces
their delicate sensibility. Now it sometimes hap-
pens 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 atmos-
phere, rest upon the eye: fies and dust lodge under
the eyelids, without producing sensation, and with-
out exciting either the hydraulic or the mechanical
apparatus to act for the purpose of expelling them.
But although they do not give pain, they neverthe-
less stimulate the surfaces so as to produce inflamma-
tion, and that causes opacity in the fine transparent
membranes of the eye; and the organ is lost, al-
though 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 that when 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 or-
gan, 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 peculiar 'na-
ture 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 it
the point of the finger be pressed somewhat rudely
* They are stated at length in my papers in the Philosophical
Transactions, and in the Appendix of my work on the Nervous System.
, 11*


126
SENSIBILITY OF THE HEART.
between the eyelids, and directly on the eye itself, he
can by such means hold the eye steady for his intend-
ed operation, producing hardly any sensation, certain-
ly no pain! '
This is one of the little secrets of the art; the Ocu
list turns out the eyelids, and fingers 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 dexterity as to inflict no pain,
when by daily experience 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 sensi-
bility which is so adjusted as to excite the action of
its protecting 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 deli.
cate sensibility and involuntary 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 denied that but for the
pain to which the eye is exposed, we should quickly
lose the enjoyment 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 dis-
coverer 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 marvellously 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
expressed a desire that Harvey should be permitted
to see the youth and examine his heart. 6 When,"
says Harvey, “I had paid my respects to this young


SENSIBILITIES OF EXTERNAL PARTS, &c. 127
“ nobleman, and conveyed to him the king's request,
“ he made no concealment, but exposed the left side
56 of his breast, when I saw a cavity into which I
56 could introduce my fingers and thumb; astonished
so with the novelty, again and again I explored the
6 wound, and first marvelling at the extraordinary
6 nature of the cure, I set about the examination of
66 the heart. Taking it in one hand, and placing the
« finger of the other on the pulse of the wrist, i
66 satisfied myself that it was indeed the heart which
6 I grasped. I then brought him to the king that
66 he might behold and touch so extraordinary a thing,
s and that he might perceive, as I did, that unless
66 when we touched the outer skin, or when he saw
56 our fingers in the cavity, this young nobleman
$ knew not that we touched his heart !" Other ob-
servations confirm this great authority, and the heart
is declared insensible. And yet, the opinions of man-
kind must not be lightly condemned. Not only does
every emotion of the mind affect the heart, but every
change in the condition of the body is attended with
a corresponding change in the heart: motion during
health--the influerice of disease-every passing
thought will influence it. Here is the distinction
inanifested. 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 against in-
jury from without, the heart, insensible 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 constitutional powers.' . .
When we consider these facts, we can no longer
doubt that the sensibilities of the living frame are ap-
propriate endowments; not qualities necessarily aris-
ing 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-


128
PLEASURABLE SENSATIONS COULD NOT
tection. We perceive that the sensibilities vary in
an extraordinary manner as they are given to exter-
nal or to internal parts, as they belong to one appara-
tus 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 overbalanced by great and essential advan-
tages-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 exquisitely contrived is the
apparatus for its protection, and the more peremptory
the call for the activity of that mechanism. The
motive to action admits of no thought and no hesita-
tion, 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 fo-
reign to my subject to speak of the pains which result
from disease, or to reconcile those who suffer in an
extraordinary degree to the dispensations of Provi-
dence. But as a witness I may speak. It is my dai-
ly 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 in-
sufferable pain and certain death. Yet these wards
are not the least remarkable for the composure and
cheerfulness of their inmates. The individual who
suffers has a mysterious counterbalance to that con-
dition, which to us who look upon her, appears to be
attended with no alleviating 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


HAVE BEEN THE MOTIVES TO ACTION.
129
our condition, our sensations and pleasures, there
must be variety in the impressions ; such contrast and
variety are common to every variety 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 in-
sensible to that colour, and opposite colours to each
other are necessary for a perfect impression., So have
we seen that in the insensibilities of the skin varia-
tions 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 suppose an
entire change of our nature, its opposite is also
implied. Nay, further, in this fanciful condition of
existence, did anything of our present nature prevail,
emotions purely of pleasure would lead to indolence,
relaxation, and indifference. To what end should
there be an apparatus to protect the eye, since plea-
sure could never move us to its exercise ? Could the
windpipe 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 exquisite sensibility of
the throat has upon the act of respiration, or those
forcible yet regulated exertions, which nothing but
the instinctive apprehension of death could excite?
To suppose that we could be moved by the solici.
tations 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 o.
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 altogether


130
PAIN NECESSARY TO EXISTENCE.
another state of existence, and the philosopher 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
I, THE SENSE OF TOUCH.
· ALTHOUGH we are most familiar with the sensibili.
ty of the skin, and believe that we perfectly under-
stand the nature of the impressions upon it and the
mode of their conveyance to the sensorium, yet there
is a difficulty in comprehending 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 satisfied
on finding that in the ear there was a little drum and
a bone to play upon it, with an accompanying nerve.
This was deemed a sufficient explanation of the
organ of hearing. It was thought equally satisfacto-
ry if in experimenting upon the eye, the image was
seen painted at the bottom of it 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 impression, or of the
manner in which it is transmitted 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 sub-
stance and in structure. The disturbance of the
extremity of the nerve, the vibrations upon it, or the
images painted upon its surface, cannot be transmit-
ted 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 suggest-
ed in the mind. All that we can say is, that the
agitations of the perves of the outward senses are the


ORIGIN OF IDEAS.
133
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 that by a deviation
from truth in the first instance, they have been en-
tangled in a tissue of deceit; and have at last been
forced into admissions which demonstrated their fol-
ly and weak inventions. I have had pity for such
patients when they have been the subjects of nervous
disorders which have produced extraordinary sensi-
bility in their organs such as a power of hearing
much beyond our common experience; for it has at-
tracted high interest and admiration, and has gradu-
ally led them to pretend to powers greater than they
actually possessed. In such cases it is difficult to
distinguish the symptoms of disease, from the pre-
tended gifts which are boasted of.
Experiment proves, what is suggested by Anatomy,
that not only the organs are appropriated to particular
classes of sensations, but that the nerves, intermediate
between the brain and the outward organs, are re-
spectively 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 ideas of vision, of hearing, of smelling, or of tast-
ing; not solely because the extremities of these nerves,
individually, are suited to external impressions, but
because the nerves are, through their whole course
and wherever they are irritated, capable of exciting
in the mind the idea to which they are appropriate,
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.
12


134
MORBID SENSATIONS.
On this circumstance, of every nerve being appro-
priated to its function, depend the false sensations
which accompany the morbid irritation of them from
internal causes, when there is in reality nothing pre-
sented externally ;—such as flashes of light, ringing
of the ears, and bitter taste or offensive smells.
These sensations are caused, through the excitement
of the respective nerves of sense, by derangement of
some internal organ, and most frequently of the sto-
mach. .
But my chief object is to show that the most per-
fect 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 presented to the outward sense and the
idea of it are connected, must ever be beyond our
comprehension, they are, notwithstanding, indis.lu-
bly united ; and when the object is so presented to
us, it is attended with the conviction of its real exis-
tence-a conviction independent of reason and to be
regarded as a first law of our nature. in
The doctrine of vibrations acting on the nerve of
vision, has had powerful advocates in our day. But
it is quite at variance with anatomy, and assumes
more than is usually granted to hypotheses. It
requires that we shall imagine the existence of 'an
ether; and that this fuid shall have laws unlike
anything of which we have experience. It supposes
a nervous fluid and tubes of fibres in the nerve, to
receive and convey these vibrations. It supposes
everywhere motion as the sole means of propagating
sensation.
These opinions have been formed on the miscon-
ception that if a certain kind or degree of vibration
be communicated to any nerve, this particular motion
must be propagated to the sensorium, and a corres-
ponding idea excited in the mind. For example, it
is conceived that if the nerve of hearing were placed :


ORGAN OF TOUCH.
(37
all animals from the lowest to the highest in the
chain of existence.
.. While 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 that enjoy many organs of sense, that of
touch, as we shall presently show, is necessary to the
full developement of the powers of all the other organs.
.
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 hardness, 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 combination 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 organiza-
tion resembles that of the other senses. ..
We have said before that, on the most minute ex-
amination of the extremity of a nerve, no appropriate
structure can be detected ; and that the nerves ex-
panded on the organs of sense appear every where the
same,soft, pulpy, prepared for impression, and so
distributed that the impression shall reach them.
What is termed the structure of the organs of sense,
is that apparatus by which the external impression is
conveyed inwards, and by which its force is concen-
trated on the extremity of the nerve. The mechan-
ism 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 re-
sembling things of human contrivance) the design
12*


ORGAN OF TOUCH.
139
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 familiar 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 continually
separating in thin scales, whilst it is as regularly
formed anew by the vascular surface below. The
condition of this covering is intimately connected with
the organ of touch. The habit of considering things
as produced accidentally, has induced some anato-
mists to believe that the cuticle is formed by the har-
dening 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 struc-
ture, 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 accomplished is not with-
out 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 formed broad
and shield-like,* in order to sustain the elastic cush-
ion which forms their extremity; and the fulness
and elasticity of the ends of the fingers adapt them
admirably for touch. But on a nearer inspection, we
see a more particular provision in the points of the
fingers. Wherever the sense of feeling is most ex-
quisite, there are minute spiral ridges of cuticle.-
These ridges have, corresponding with them, de-
pressed lines on the inner surface of the cuticle ; and
these again give lodgement to a soft pulpy matter, -
in which lie the extremities of the sentient nerves.
There the nerves are sufficiently protected, while they
are exposed to impressions through the elastic cuticle,
* Unguis scutiformis.


140
ORGAN OF TOUCH.
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 admired in this thick,
ening of the cuticle is, that the sense of touch is not
lost, or indeed diminished, certainly not at all in pro-
portion to the protection afforded by the thickened skin.
The thickened cuticle partakes of the structure of
the hoofs of animals: and we shall now attend to the
nature of the hoof, as the best possible illustration of
the manner in which the sensibility 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 that which exists, but is only more minute
and delicate, in the fingers. We may take the horse's
foot as the example. When the crust or hoof, which
is insensible, is separated from the living part, we see
small villi hanging from the vascular surface, and
which have been withdrawn from the crust; looking
to the inside of the crust, wé perceive the pores froin
which these villi have been pulled. These processes
of the living surface are not merely extremities of
nerves ; they consist of the nerves and the necessary
accompaniments of membrane and bloodvessels; 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


ORGAN OF TOUCH.
141
the circulating blood. These nerves, so prolonged
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 percussion against the
ground ; and without this provision, there would be a
certain imperfection in the limb. I
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 bearing the
percussion against the ground. But in made roads,
and with the imperfections of shoeing, the pressure
and concussion 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
à remedy for this condition in dividing the nerve ;
the consequence of which operation is, that the horse,
instead of moving with timid steps, puts out his feet
freely, and the lameness iš cured. If, however, we
were to receive the statement thus barely, the fact
would militate against our conclusion that mechani-
cal provision and sensibility go together, being equal-
ly 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 con-
traction is produced, the most common defect 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. It
has not only lost the pain which should guard against
over exertion, but the feeling of the ground, which is
necessary to his being perfectly safe as a roadster.


ORGAN OF TOUCH.
143
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 ani.
mal 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 sensibility combined with high
vascularity.
Having described the relation of the cuticle to the
nerves of touch, we may take notice of another qua-
lity, in its roughness, and of the advantages 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 iş 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 surface it
would have been but ill suited to touch : but, on the
contrary, it has a very peculiar roughness which
adapts it to feeling. A provision for friction, as op-
posed to smoothness, is à necessary quality of some
parts of the skin. 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 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 texture of the cuticle, give security in de-
scending, as their claws enable them to climb.
In concluding this section, we perceive that the
organ of touch consists of nerves appropriated to re-
ceive the impressions of bodies capable of affording
resistance. Fine filaments of those nerves, wrapt up


144
ORGAN OF TOUCH.
in delicate membrane with their accompanying arte-
ries and veins, project from the true skin into corres-
ponding 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 protected, at the same
time that they are sensible to the pressure made on
the surface, and to cutting, pricking, and heat.*
But this capacity, we repeat, is not owing, strictly
speaking, to any thing in the structure of the organ,
but to the appropriation of the nerves 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 temperature,
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
the disease seated in the centre of the thigh.


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 exception in
regard to the human offspring: that in the child we have
to trace the gradual dawn and progressive improve-
ment 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 di-
rected by sensibility 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 violence of any kind.
The hand, which is to become the instrument for
perfecting the other senses and developing the endow-
ments of the mind itself, is in the infant absolutely pow-
erless. Pain is poetically described as that power into
whose “ iron grasp" we are consigned, to be introdu-
ced 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 un-
conscious of the part of the body which suffers. We
have again recourse to the surgeon's experience.
There occur certain congenital imperfections which
require an operation 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.
13


146
OF THE MUSCULAR SENSE.
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 sensibility 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 ac-
quirement.
.. The knowledge of external bodies as distinguished
from ourselves, cannot be acquired until the organs of
touch in the hand have become familiar with our own
limbs ; we cannot be supposed 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
own body as distinguished from things external to us.
The first office of the hand, then, is to exercise 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 only in
favour of the sense of vision, when that sense has im-
proved 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 direction 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 exhi-
bited 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 strug-


: 148
OF THE MUSCULAR SENSE.
ventured on this explanation from the commence-
ment; much doubting, however, the correctness of
my reasoning, from seeing that the great authorities
on this subject made no account 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 con-
nected with my enquiries into the functions of the
nervous system, and in some measure, directed
them.
The Abbé Nollet, after extolling the sense of touch
as superior to all the other senses, and as deserving
* 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 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 was found to be a nerve
of sensation : and thus, it was proved that there is a nervous circle
connecting 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 the
muscles, there is a nerve of sensibility to convey the nervous influence
from the muscles towards the sensorium, as well as a nerve of action
for conveying the mandate of the will to the muscles. In their dis-
tribution through the body, the nerves which possess these two dis-
tinct powers 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 examining the nerves at their roots, that is,
where they arise from different tracts of the brain and spinal mar:
row, and before they have coalesced, that I suoceeded in demonstrat-
ing their distinct functions. In the face, the nerve of motion passes
by a circuitous course, apart from the nerve of sensation, to be dis-
tributed in the muscles; and therefore the distinct characters of these
nerves were more easily proved by experiment than in any other
part of the body. See the Philosophical Transactions on the “Ner-
vous Circle which connects the Voluntary Muscles with the Brain,"
and the “ Nervous System.” 4to. Longman,


OF THE MUSCULAR SENSE.
149
to be considered the genus under which the others.
should be included as subordinate species, makes this
remark—“ Besides, it has this advantage over them,
6 to be at the same time both active and passive ; for it
6 not only puts it in our power to judge of what makes
“ an impression upon us, but likewise of what resists
“ our impulsions." The mistake here lies in giving
to the nerves of touch a property which must belong
to the actions of muscles. So it is affirmed by phy-
siologists, 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 considering the
muscular agency, which is directed by the will dur-
ing the exercise of touch, as belonging to the nerve
of touch properly. We 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 pedestal, or the wind will cast it down.
How is it, then, that a man sustains the perpendicu-
lar 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 inclination of his
body, and that he has a ready aptitude 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 ob
served 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 de.
velopement 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
13*


150
OF THE MUSCULAR SENSE.
.
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 exertion 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 ex-
ternal body. In truth, we stand by so fine an exer.
cise 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 know this position of the
members of our body : and what can this be but a
consciousness of the degree of action and the adjust-
ment 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 consciousness
of the degree of effort which was directed to them in
volition. It was with a view to elucidate this, that I
made the observations which terminated in the dis-
covery 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 récollection of the ac-
tion which placed them where they are ; it must,
therefore, be a consciousness of their present condition.
When a person in these circumstances moves, he has
a determined object; and he must be conscious of a
previous condition before he can desire a change or
direct a movement.


OF THE MUSCULAR SENSE.
151
After a limb has been removed by the surgeon, the
person still feels pain, and heat, and cold in it. Urg-
ing a patient to remove 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 remain-
ed, but as if it were placed or hanging in a particular
position or posture. I have asked a patient-"Where
do you feel your arm now?" and he has said, “ I feel it
as if it lay across my breast,” or that it is “ lying
6 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 deceptious sensibility to the
condition of the muscles, as well as to the condition
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 condition 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 analogous organ : for example, in the
palpa or tentacula of the lower animals. These ani.
mals use those instruments to grope their way: and
they consist of a rigid tube containing a pulpy mat-
ter, in which there is a branch of nerve that possesses
in an exquisite degree the sense of touch. Now when


OF THE MUSCULAR SENSE.
153
six feet. The zeus insidiator* has also the power of
forming its mouth into a tube and squirting at flies so
as to encumber their wings and bring them to the
surface of the water. Whether led to admire the
wonderful power of instinct in these inferior crea-
tures, or the property acquired by our own eye, we
must acknowledge 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,
that impression on the nerve of vision 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. We can judge of the direction of sounds
without turning the head, because the strength of
vibration is unequal on the two sides of the head, and
a comparison is made of the two impressions. But
when a person is deaf of 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 company, where there are many speakers,
he appears positively deaf, from the impossibility of
distinguishing minutely the direction of sounds.
The last proof of the necessity of the combination
of the muscular sense with the sense of contact will
be conclusive. The following is not a solitary in-
stance :
A mother while nursing her infant was seized with
* Belonging to another genus of the same Order. .
| In these instances a difficulty will readily occur to the reader;
how does the fish judge of position, since the rays of light are refract-
ed at the surface of the water ? Does instinct enable it to do this,
or is it by experience ?


154
OF THE MUSCULAR SENSE.
a paralysis, attended by the loss of power on one side
of her body, and the loss of sensibility on the other
side. The surprising, and, indeed, the alarming cir-
cumstance here was, that she could hold her child
to her bosom with the arm which possessed muscular
power, but only as long as she looked at the infant.
If surrounding objects withdrew her attention from
the state of her arm, the flexor muscles gradually
relaxed and the child was in danger of falling. The
details of the case do not belong to our present en-
quiry ; but we see here, first, that there are two pro-
perties in the arm ; which is shown by the loss of
the one and the continuance of the other; secondly,
that these properties 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 direct it.
The property in the 'hand of ascertaining the dis-
tance, the size, the weight, the form, the hardness
and softness, the roughness or smoothness of objects
results from the combined perception-through the
sensibility of the proper organ of touch and the mo-
tion of the arm, hand, and fingers. But the motion
of the fingers is especially necessary to the sense of
touch; they bend, extend, or expand, moving in all
directions like palpa, with the advantage of embrac-
ing the object, and feeling it on all its surfaces; sen-
sible to its solidity and to its resistance when grasped ;
moving round it and gliding over its surface, and,
therefore, feeling every asperity..
THE PLEASURES ARISING FROM THE MUSCULAR SENSE.
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 sense ; and to this
source, also, we must trace some of our chief enjoy-
ments. We may, indeed, affirm that it is benevolently


156
OF THE MUSCULAR SENSE.
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 disposi-
tion 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 established the closest connection be-
tween the enioyments 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.


CHAPTER X.
THE HAND NOT THE SOURCE OF INGENUITY OR CON- .
TRIVANCE, NOR CONSEQUENTLY OF MAN'S SUPE-
RIORITY.
Seeing the perfection of the hand, we can hardly
be surprised that some philosophers should have en-
tertained the opinion with Anaxagoras, that the supe-
riority of man is owing to his hand. We have seen
that the system of bones, muscles, and nerves of this
extremity is suited to every form and condition of. ver-
tebrated 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 perceive,
consists in its power, which is a combination 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, spin-
ning, weaving, and constructing ; properties which
may be found in other animals, but which are com-
bined to form this more perfect instrument.
In these provisions the instrument corresponds with
the superior mental capacities, the hand being capa-
ble of executing whatever man's ingenuity suggests.
Nevertheless, the possession of the ready instru.
ment is not the cause of the superiority of man, nor
is its aptness the measure of his attainments. So
that we rather say with Galen--that man had hands
given to him because he was the wisest creature,
than ascribe his superiority and knowledge to the
use of his hands. *
* Ita quidem sapientissimum animalium est homo; ita autem et
manus sunt organa sapienti animali convenientia. Non enim quia
14


158
THE HAND NOT THE
This question has arisen from observing the perfect
correspondence between the propensities of animals
and their forms and outward organization. When
we see a heron standing by the water side, still as a
grey stone, and hardly distinguishable from it, we
may ascribe this habit to the acquired use of its feet,
constructed for wading, and to its long bill and flex.
ible neck; for the neck and bill are as much suited
to its wants as the lister 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 hiņder extremities by the side of a stream,
in the morning or evening, like a practised fisher;
there he will watch, so motionless 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 incredible 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 posses-
sion of the instinct without the appropriate organ,
we can the more readily believe that, in other exam-
ples, the habit exists with the instrument, although
not through it.
The canine teeth are not given without the carni-
vorous appetite, nor is the necessity of living by car-
nage joined to a timid disposition; but boldness and
fierceness, as well as cunning, belong to the animal
with retractile claws and sharp teeth, and which prey
on living animals.* On the other hand, the timid
vegetable feeder has not his propensities produced by
manus habuit propterea est sapientissimum, ut Anaxagoras dicebat :
sed quia sapientissimum erat, propter hoc manus habuit, ut rectissime
censuit Aristoteles. Non enim manus ipsæ homines artes docuerunt,
sed ratio. Manus autem ipsæ sunt artium organa: sicut lyra, mu-
sici, et forceps, fabri.
* In some of the quadrumana, the canine teeth are as long and
sharp as those of the tiger-but they are in them only instruments
of defence, and have no relation to the appetite, or mode of diges-
tion, or internal organization.


SOURCE OF INGENUITY.
159
the erect ears and prominent eyes ; though his dis-
position corresponds with them in his suspicious-
ness and timidity. 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 him
bv instinct to strike with his horns : and he will so push
whether he has 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), al-
though wanting horns, is always the most mischiev-
ous. When that noble animal, the Brahmin bull, of
the Zoological Gardens, first put his hoof on the sod
and smelt the fresh grass after his voyage,-placid
and easily managed before, he became excited, plung-
ed, and struck his horns into the earth, and ploughed
up the ground on alternate sides, with a very remark-
able 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,
be strange, where all else is perfect, if the instinctive
character or disposition of the animal were at vari-
ance with its arms or instruments.
But the idea may still be entertained that the acci-
dental use of the organ may conduce to its more
frequent exercise and to the production of a corres-
ponding disposition. Such an hypothesis 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 Humphry Davy
relates that a friend of his having discovered under the
burning sand of Ceylon, the eggs of the alligator, he
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 in-
fluence of the sunbeams in the burning sand, it made
towards the water, its proper element : when hinder-
ed, it assumed a threatening aspect and bit the stick


160
INSTINCT OF THE YOUNG ANIMAL.
presented to it. As propensities to certain motions are
implanted in animals, to which their external organs
are subservient, so are passions given as the means
of defence or of obtaining food. But this has been
well said seventeen hundred years ago. 6 Take,"
says Galen, “three eggs, one of an eagle, another
6 of a goose, and a third of a viper; and place them
" favourably for hatching. When the shells are
6 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."
When we direct the enquiry to the comparison of
man's faculties with his outward organization, the
subject has increased interest. With the possession
of an instrument like the hand there must be a
great part of the organization, which strictly belongs
to it, concealed. The hand is not a thing appended,
or put on, like an additional movement in a watch ;
but a thousand intricate relations must be established
throughout the body in connection with it -such as
nerves of motion and nerves of sensation : and there
must be an original part of the composition of the
brain, which shall have relation to these new parts,
before they can be put in activity. But even with
all this superadded organization the hand would lie
inactive, unless there were created a propensity to
put it into operation.
I have. been asked by men of the first education
and talents whether any thing really deficient had
been discovered'in the organs of the orang-outang to
prevent him from speaking! 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 muscles of respiration;
in the second place, the vocal chords in the top of


162
THE INGENUITY OF THE HAND
guish and admire, then are its features in action; its
voice begins to be modified into a variety of sounds ;
these are taken up and repeated by the nurse, and
already a sort of convention is established between
them. We cannot, therefore, doubt that a propensity
is created in correspondence with the outward organs,
and without which they would be useless appendages.
The aptness of the instrument or external organ will
undoubtedly improve 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 revolu- ,
tion which took place when language, till then limite
ed 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. Nations will
not now record their acts by building pyramids, nor
consecrate temples and raise 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."
Buffon has attempted to convey to us the mode in
which knowledge may have been acquired by watch-
ing (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 him raise his
wondering eyes to Heaven and spring up by quick
instinctive motion as “thitherward endeavouring,” he
substitutes a bad combination of philosophy with
eloquence.


HAS MADE A REVOLUTION IN THE ARTS.
163
“To place the subject more distinctly before us,”
says Buffon, “the first created man shall speak for
“himself;" and the sentence which he is made to utter
is to the effect," that he remembers the moment
“ of his creation that time, so full of joy and trouble,
“when he first looked round on the verdant lawns and
“crystal fountains, and saw the vault of Heaven over
“his head ;"—and he proceeds to declare, “that he
"knew not what he was or whence he came, and be-
"lieved 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, sup-
poses a thousand disagreeable associations 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 con-
ceive that philosophy must lead to something very
different from what they haýe been early taught:
hence the absurdity of this combination 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 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 happened 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 beauty and profusion-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 desire to know how a
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


164
CHANGES IN THE GLOBE
.
must have perished ; and if mature in body, he must
have been created with faculties suited to his condi-
tion. 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 ear-
ly taught to believe.
In every change which the globe has 'undergone,
we see an established relation between the animal
created, and the elements around it. It is idle to sup-
pose this a matter of chance. Either the structure
and functions of the animal must have been formed
to correspond with the condition of the elements, or.
the elements must have been controlled to minister.'
to the necessities of the animal ; and if the most care- .
ful investigation lead us to this conclusion, in con-
templating all the inferior gradations of animal exis-
tence, what is it that makes us so unwilling to ad-
mit such an influence in the last grand work of
creation ?
We cannot resist those proofs of a beginning, or of
design prevailing everywhere, or of a First Cause.
When we are bold enough to extend our inquiries in-
to the great revolutions which have taken place,
whether in the condition of the earth or in the struc-
ture of the animals which have inhabited it, our no-
tions 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 previ-
ously existing, or now existing: and 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
conviction is implanted in our nature that we should
rely on the course of events, as permanent and neces-
sary. 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


AND SUCCESSIVE EPOCHS.
165
constrained, and our conceptions, as well as our lan-
guage, imperfect. We must either abandon these
speculations altogether, 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 itself;—that their living
endowments bear à relation to their state of exis-
tence and to the elements around them. We have
learnt that the system of animal bodies is simple and
universal, notwithstanding the amazing diversity of
forms that meet the eye-and that this system not
only, embraces all living creatures, but that it has been
in operation at periods of great antiquity, before the
last revolution of the earth's surface had been accom-
plished..
The most obvious appearances and the labours of
the geologist 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 of revolu-
tions : and that in the course of these revolutions there
have been long periods or epochs. In short, progres.
sive 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 stratified
rocks---the lowest simple, or perhaps chemical ; the
strata above these, compound; and successively others
more conglomerated, or more distinctly composed of
the fragments of the former-it is not easy to contra-


166
COMPARISON OF SOME PARTS OF THE
dict the hypothesis of an eternal 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 sub-
mitted 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 species of
animals, which countenances the notion of a return
of the world to any former condition. When we ac-
knowledge that animals have been created in suc-
cession and with an increasing complexity of parts,
we are not to be understood as admitting that there
is here proof of a growing maturity of power, or an
increasing effort in the Creator; and for this very
plain reason, which we have stated, that the bestow-
ing of life or the union of the vital principle with the
material body, is the manifestation of a power supe-
rior to that displayed in the formation of an organ or the
combination of many organs, or construction of the
most complex mechanism. It is not, therefore, a
greater power that we see in operation, but a power
manifesting itself in the perfect and successive adap-
tation of one thing to another-of vitality and organi-
zation to inorganic matter.
In contemplating the chain of animal creation, we
observe that even now, there are parts of the earth's
surface which are marshy, and insalubrious, 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 in-
teresting 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 surface was flat,
and that it produced such plants as imply a similar
state of the earth to these swampy and unhealthy
regions..
We mark changes in the earth's surface, and ob-


ADDITIONAL ILLUSTRATIONS.


- ADDITIONAL ILLUSTRATIONS.
THE MECHANICAL PROPERTIES OF THE SOLID STRUC-
TURE OF THE ANIMAL BODY CONSIDERED.
I YIELD to the suggestion of friends in further pur-
suing the subject of the solid textures of the animal
frame, with the proofs of design which are exhibited
in its mechanical provisions.
It has been shown in the first chapter that solidity
and gravity are qualities necessary to every inhabitant
of the earth : the first to protect 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 be-
stows this necessary firmness on the animal textures,
is the cellular substance. This consists of delicate mem-
branes, 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 constitutes 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 strongest bones ; it is the medium be-
tween bone, muscle, and blood-vessel : it produces à
certain firmness and union of the various component
parts of the body while it admits of their easy motion.
Without it, we should be rigid, notwithstanding the
proper organs for motion; and the cavities could not
be distended or contracted, nor could the vessels
pulsate.
But this cellular texture is not sufficient on all oc-
casions, either for giving strength or protection: nor


172
ADDITIONAL ILLUSTRATIONS
does it serve to sustain the weight, unless the animal
live suspended in water, or creep 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 vo- .
lume: 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 larvæ 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 re-
sistance, or their muscles would be useless. Their
skins suffice; they are hardened by a deposit within
them for this purpose ; but if this skin were not fur-
ther provided, it would be rigid and unyielding, and
be no substitute for bone. These hardened integu-
ments are, therefore, divided into rings ; to these the
muscles are attached ; and as the cellular membrane
between the rings is pliant, these annelides can creep
and turn in every direction.
Without further argument, we perceive how the
skin, by having a hard matter deposited in it, is adap-
ted 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 some-
thing 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, did it not appear that


OF THE MECHANICAL PROPERTIES.
173
the apparatus is more perfect than in some of the ani-
mals which have a true skeleton. The resisting ma-
terial is here deposited externally, and is converted to
every purpose which we have seen attained by means
of the skeleton. Distinct members are formed, with
the power of walking, leaping, flying, holding, spin-
ning, and weaving. The hardened integuments,
thus articulated and performing the office of bones,
have, like them, spines and processes : with this dif-
ference, that their aspect is towards the centre, instead
of projecting exteriorly. Were we to compare the
system of “ resisting parts" in man and in the insect,
we should be forced to acknowledge the mechanical
provisions to be superior in the lower animal ! The
first advantage of the skeleton (as we may be permit-
ted to call the system of hard parts in the insect) be-
ing external and lifeless, is, that it is capable of hav-
ing 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 penetrated with blood
vessels; and therefore must be porous and soft. The
next advantage is mechanical. The hard material is
strong to resist fracture, and to bear the action of mus-
cles, 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
further thrown off from the axis.
When considering the larger vertebral animals, we
had reason to say that there is a correspondence be-
tween the resistance of the bones and the power of
the muscles, and we may indulge the same reflection
here. As the integument covering the insect is much
harder than bone, so are the muscles stronger, com-
pared 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.
15*


176
ILLUSTRATIONS OF THE
ing a certain swing and elasticity. It lately happen-
ed that a bridge of this kind fell in very curious cir-
cumstances,--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 with-
stood 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 adjust-
ment of the material in the animal fabric; not mere.
ly to enable it to sustain the incumbent weight, or
transverse or oblique impulses, but to withstand the
frequent, and regularly 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
but what has a constitution of its own, adjusted to its
place and use : the heel bone, the shin bone, the ver-
tebræ, and the bones of the head, differ in mechani.
cal, construction.. But the consideration of these
adaptations in the constitution of the bones makes
some general remarks necessary.
Perfect security against accidents in the animal
body, and in man especially, is not consistent with the
scheme of nature. Without the precautions and the
continued calls to exertion, for safety, which danger
and the uncertainty of life produce, many of the fa-
culties of the mind would remain unexercised; and
whence else would come courage, resolution, and all
the manly virtues ? Take away the influence of the
uncertain duration of life, and we must suppose also
a change in the whole moral constitution of man.
Whether we consider the bones as formed to protect
the part, 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 derangements. from accident. The me-
chanical adaptations which we have to observe are


MECHANICAL PROPERTIES OF BONE.
177
perfectly sufficient to their ends, and afford safety in
the natural exercises of the body. To these exer-
cises there is an intuitive impulse, ordered with a re-
lation 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 derangement and accident, and to be-
come, in the course of life, more and more fragile,
until by some failure in the frame-work or vital ac-
tions, life terminates.
The bones of the extremities are called hollow
cylinders. Now, after we have convinced ourselves
of the necessity of this formation, we find these bones,
upon a more particular examination, extremely varied
in their shapes; and we are, at last, prone to believe
that there is much of chance or irregularity in their
shapes; 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 ; and, in the
second place, why they vary in their shape, so as to
appear to the superficial observer irregular.
The reasoning that applies to the hollow cylindrical
bone serves equally to explain 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 accu-
sed of having denied that there was a God; when pick-
ing up a straw that had stuck to his garments, he
said, “ If there were nothing else in nature to teach
6 me the existence of a Deity, this straw would be
6 sufficient.” It hardly requires demonstration to


MECHANICAL PROPERTIES OF BONE.
181
With regard to the articulation of the bones, we
cannot mistake the reason of the surfaces of contact
being enlarged. In machinery it is found that, if
the pressure be the same, the extension of the sur-
faces in contact does not increase the friction. If, for
example, a stone or a piece of timber, of the shape of
a book or a brick, should be laid upon á flat surface,
it would be drawn across it with equal facility, whe-
ther it rested upon its edge or upon its side. The fric-
tion of the bones which enter into the knee joint is
not increased by their greater diameter : while great
advantages are gained; the ligaments which knit
these bones give more strength than they otherwise
would, and the tendons which run over them, being
removed to a distance from the centre, have more
power.
THE MUSCULAR AND ELASTIC FORCES.
The muscular power is contrasted with the elastic,
as possessing a living property of motion. We acqui-
esce 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 pro-
perty of elasticity in the living body which cannot be
retained after death. To illustrate this we shall take
the instance of the catgut string of a harp. Suppose
that the string is screwed tight, so as to vibrate in a
“strong enough to bear a proportioned increase of weight: granite
“ must be placed in its stead; and even the granite would not be
capable of sustaining four times the weight which the soft stone
bore in the 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 would crush them. The same principle is applicable
"l to the bones of animals. The material of bone is too soft to admit
" an indefinite increase of weight; and it is another illustration of
“ what was before stated, that there is a relation established through
" all nature : that the very animals which move upon the surface of
“ the earth are proportioned to ils magnitude, and the gravitation to
“ its centre."-Animal Mechanics.
16


182
OF ELASTIC PARTS.
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 body are, the
more carefully is the proper tension 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 properties; and if heated again to
500 of Fahrenheit, 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 restoration
which the steel has not.
If a piece of fine mechanism be made perfect by
the workman, it may be laid by and preserved; but
it is very different with the animal body. The me-
chanical properties of the living frame, like the endow-
ments of the mind, must not lie idle, or they will suf-
fed 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 acknow-
ledge, but the property of resistance is destroyed; and
bones, and tendons, and ligaments quickly degene-
rate. *
This subject is illustrated in the Essay on Animal Mechanics,
Part II.


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 in the most delicate of all the organs
of the body, we naturally turn to the eye: and this
organ suits our present purpose the better, that we
have to show how much of the sense of vision de-
pends on the hand, and how strict the analogy is
between the two organs.
From the time of Sir Henry Wotton to the latest
writer on light, the eye has been a subject of admi-
ration and eulogy. But I have ventured, on a former
occasion,* to say, that this admiration 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 apparatus, as much as to its humours
and the proper nerve of vision. It is to the muscu-
lar apparatus, and to the conclusions which we are
enabled to draw from the consciousness of muscular
effort, 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 under-
stood the effect and uses of a theodolite, on estimat-
ing 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 con
fining his study to the naked ball. :
We must begin our observations by a minute atten-
tion 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 con-
tained between two menibranes of extreme fineness,
and these membranes both support it and give to its
* See Philosophical Transactions,


184
COMPARISON OF THE EYE
surfaces a mathematical correctness. The matter
of the nerve, as well as these supporting membranes,
are perfectly transparent, during life; and on the
axis of the eye, there is a small portion which remains
transparent, when the rest of the membrane becomes
opaque, and which has been mistaken for a foramen, *
or hole in the 'retina. It is surprising, that with all
the industry whieh 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 ob-
serving the phenomena of vision, and especially the
extreme minuteness of the image cast upon the reti-
na, 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 membrane, when floated in
water and under a magnifying 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 con-
stitutes a net-work : and the expressions of some of
our first modern authorities would induce us to be-
lieve that they view it in this light, as corresponding
with their hypothesis. But there is no fibrous tex-
ture 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 retina, presents something
of this appearance. '
Vision is not excited by light unless the rays pene-
trate 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
* It is this part which is called the foramer of Soemmerring.


186
COMPARISON OF THE EYE
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 better
prove the distinct office of the nerve as contrasted
with the expanded retina, than this circumstance,
that when the strongest ray of light strikes into the
nerve itself, the impression is not received. It seems
to imply, that the capacity of receiving the impres-
sion, and of conveying it to the sensorium, are two
distinct functions.
Is not this opinion more consistent with the phe-
nomena than what is expressed by one of our first
philosophers, that the nerve, at its extremity towards
the eye, forms what has been called the punctum coe-
cum, and is insensible, 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.
Independently of this punctum cæcum, we have
to observe that the whole surface of the retina is not
equally sensible to light. There is a small spot, op-
posite to the pupil and in the axis of the eye, which
is more peculiarly sensible 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 contrary, see
reason to conclude, that the sensible spot is not limit.
ed to an exact circle, that it is not regularly defined,
and that the sensibility, in fact, is increasing to the
very centre.
Some have denied the existence of this extreme
sensibility in the centre of the retina, attributing the
distinctness of the vision to the circumstance 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 gradu,
ally from its utmost circumference to the point which
forms the axis of the eye.


188
COMPARISON OF THE EYE
cise of the organ; and to this may be attributed the
high perfections of it.
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 accommo-
date 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 the instinct of the duck, when it runs to
the water the moment that the shell is broken, con-
tradicts the fact that the child learns to stand and
walk after a thousand repeated 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 pic-
tures, the cornice, the chairs; but we are deceived :
being unconscious of the motions of the eye, and that
each object is 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 other-
wise. 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; and 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 cor-
ner of the frame of the principal picture in the room.
At first, every thing around it is distinct; in a very
little time, however, the impression 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


WITH THE HAND.
189
becomes dim. When we have thus far ascertained
the fact, we change the direction of the eye, but ever
so little, and at once the whole scene is 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 becomess less sensible to it, but more
sensible to a ray of the 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 mo-
tion of the eye is to the continued exercise of the
organ.
Before dismissing this subject, we may give ano-
ther 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 en-
deavour to scrutinize the object, fixing the eye in-
tently upon it, it disappears; 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 obvious: the retina is exhausted, but becomes
recruited by looking on the other objects of different
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.
Here we may interrupt our inquiry to observe how
inconsistent these phenomena are with the favourite
hypothesis-that light produces vision by exciting


190
COMPARISON OF THE EYE
vibration in the fibres of the nerve. By all the laws
of motion from which this hypothesis is borrowed,
we know that if a body be set in motion, it is easily
kept in motion; and that if a cord vibrate, that vi.
bration 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 cords of a
musical instrument, they would be most easily con-
tinued in motion by undulations in the same time :
that if the red ray oscillated or vibrated in a certain pro-
portion of time, it would keep the fibres of the nerve
in action more easily, than a green ray, which vi-
brates in a different time. If the colour of a ray
depended upon the peculiar undulation or vibration,
it appears that 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 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 forcè, often ap-
“plied 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 continual 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 repeated one, produces no light. And thus also
“ may the vibrations excited in the retina continue a sensible time af-


WITH THE HAND.
191
Reverting to the sensible spot in the retina, it does
not appear that we are authorized in terming it a
spot. The same law governs vision when we look to
a fine point of a needle, or to an object in an exten-
sive 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 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 the sen-
sibility to impression; and this holds whether we are
looking abroad in the country, or are microscopically
intent upon objects of great minuteness.
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 ad-
justed to the other with such marvellous precision? and
how do the eyes move together 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 successively 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 extraordinary minuteness, this action of the
« ter the exciting cause has ceased, prolonging the sensation of ligh
“ (especially if a vivid one) for an instant in the cye in the manner
* described.” Sir W. Herschell, Art. Light. Enc. Met.
Now it does appear to me that this reasoning is inconsistent with
the phenomena above noticed.


192
COMPARISON OF THE EYE
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 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 mus-
cles of the eye is necessary to perfect vision, when the
gradual acquisition of the power may be seen in observ-
ing 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 search-
ing action of the eye: but, by, and bye, the eye fol-
lows 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 expe-
rience 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 independent of
experience. We must acknowledge 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 faculty 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


194
COMPARISON OF THE EYE
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 ray that falls
upon the retina. 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 obliquity 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 direc-
tion 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 knowledge, 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 magnify-
ing one object in a high degree, cannot be directed
in the heavens, the observer seeing nothing but that
one object ? Accordingly to remedy this, there is
mounted on the greater telescope a smaller one, ex-
actly parallel, of lesser Power, but commanding a
greater field : this finder, the astronomer directs to
the constellation and moves from star to star, until
that which he desires to examine is in the centre of
the field : and by this means he adjusts the larger
telescope to his object. Is this not a correct illustra-
tion of the operation of the eye ? is the eye not im-
perfectly 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 the other,
* See a paper by Mr. Alexander Shaw, who has explained this
subject very happily --Journal of the Royal Institution, 1832.


WITH THE HAND.
197
finest organ of sense, which so largely contributes to
the developement of the powers of the mind, would
lie unexercised.
THE MOTION OF THE EYE CONSIDERED IN REGARD
TO THE EFFECT OF SHADE AND COLOUR IN A PIC-
TURE,
A QUESTION naturally arises whether it be possible,
from this part of philosophy, to suggest some princi-
ples for the amateur and painter. The ideas and lan-
guage of the amateur, when he attempts to establish
rules for the disposition of colours or shades in a pic-
ture, are certainly very vague.
We have to remark, in the first place, that the co-
lours of nature, and those of objects when represented
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 are sent 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 reflected and mingled. The next difference re-
sults from the atmosphere, through which the rays
from distant objects proceed to the eye and are soften-
ed; the canvass being near the eye, the effect which
the atmosphere produces on colours amounts to no-
thing in the picture. The third mode in which co-
lours are affected, is common to natural objects and
to paintings, and is connected with the law of vision
which we have been considering, and to which we
must now revert.
When we make experiments by looking upon co-
loured spots, the effect on the sensibility of the retina
is remarkable ; and as this does not occur incidentally,
but takes place, more or less, whenever we exercise
the eye, it must have its influence when we look to
works of art. - The familiar fact which we have to
carry with us into this enquiry, is, that if we throw a
17*.


198
COMPARISON OF THE EYE
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, which presently be-
comes 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 appear yellow. These
phenomena are to be explained by considering that
the nerve is exhausted by the continuance of the im-
pression, and becomes more apt to receive sensation
from an opposite colour. All the colours of the prism
come into the eye from the surface of the paper when
the wafer has been removed; but if the nerve has been
exhausted 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 perfectly correct, for although the highest
part of the tower be in the brightest illumination, it
is not seen somit 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


202
COMPARISON OF THE EYE
the flesh be, as the painter terms it, “too warm," it
may be made “cold" by rendering the eye insensi-
ble to the red and yellow rays, and more than usually
susceptible of the blue and purple rays. Every co-
loured ray from the flesh is transmitted to the eye ;
but if the eye has moved to it from a yellow or crimson
drapery, 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 preva-
lence of the opposite rays of colour.
It ought to be unsatisfactory to the philosophical
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 colours at the same time—whereas, the
effect, of whích 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 intentiy fixed upon an object, and is not permit-
ted to wander from point to point. This touches the
chiaroscuro of painting ; which is not merely the
managing of the lights and shadows, but the presery-
ing of the parts of a scene subordinate to the principal
object. There is something umpleasant and imper-
fect, even to the least experienced eye, in a picture in
which every thing is made out-the drapery of every
figure, the carving or ornament of every object minute-
ly represented; for these things were never so seen in
nature. The true picture, on the other hand, is effec-
tíve, 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 in-
sensible degrees, the painter keeps down the parts


WITH THE HAND.
203
which are removed from the centre; and thus he
represents the scene as when we look intently upon
an object-seeing that which is near the axis of the
eye distinctly—the other objects, as it were, retreating
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 we turn round and
have presented before the eye the several divisions of
the circle, in each of which 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 bene-
ficence in the capacities of the living frame, we revert
naturally to the pleasures 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 coloured rays
are also, by 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, on looking out on
the face of nature, that they are the prevailing co-
lours.* The red ray illuminates the least, but it irri.
tates the most; and it is this variety in the influence
of these rays upon the nerve that continues its exer-
cise, 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.
* The astronomer selects a glass for his telescope, which refracts
the pale yellow light in the greatest proportion, because it illuminates
in the highest degree and irritates the least. ,


ADDITIONAL ILLUSTRATIONS TO THE CONCLUDING
CHAPTER.
I have sometimes thought it possible, that a great-
ly 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 dwel-
ling on the perfection of the frame of the animal body
and the marvellous endowments of the living proper-
ties. When we have formed some estimate of the
immensity of the heavenly bodies, we are struck
with admiration in following the successive advance-
ment made in the science :--an improvement in the
curves of the glasses of the telescope, a new mode of
polishing the reflecting surfaces, a change in the
chemical composition of the glasses, or a more per-
fect adjustment of their dispersive powers-is follow-
ed by the discovery of circle beyond circle of worlds
interminably..
We fan the imagination and labour to comprehend
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 geological periods, and we ourselves
as atoms, driven about, amidst unceasing changes of
the material world. .
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 irregularity in the composi-
tion of the system. In proportion indeed as we com-
prehend the principles of mechanics, or of hydraulics,


THE
CLASSIFICATION OF ANIMALS,
IN EXPLANATION OF THE TERMS INCIDENTALLY USED IN THE
VOLUME.
THE ANIMAL KINGDOM is arranged in four Divisions :
· Division I. Vertebral Animals : so called from their possessing a ver-
tebral 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 coverings 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, and resembles the
form of a plant. Etym. Zwov, zoon, a living creature; putov, 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 the 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.
Wo present the principal Orders with familiar examples.
Bimana, man. Etym. bis, double ; manus, hand.
18*


210
APPENDIX.
Quadrumana. Etym. quatuor, four; manus, hand. Monkeys, ma-
kis or lemurs (Etym. lemures, ghosts.) The loris tardigradus (tar-
dus, slow ; gradior, to walk) is a species of lemur.
Cheiroptera. Etym. Xelp, cheir, the hand ; Ttepov, 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. apoi, amphi, both ; Bros, bios, life Walrus ; seal.
Marsupialia. Etym. marsupium, a pouch. Kangaroo ; opossum.
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
(ueya, mega, great; Jeplov, therion, a wild beast); megalonyx (ueyası
megas, great; ovuš, onyx, a claw); ornithorhynchus (opvidos ; ornis
thos, of a bird ; Quixos, rhynchos, a beak.)
Pachydermata. Etym. Taxus, pachys, thick ; depua, derma, skin,
Rhinoceros, elephant; mammoth: mastodon (uaotos, mastos, a
nipple ; odwv, odon, a tooth) ; tapir ; 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; swallow ; crow,
wren.
Scansores. Etym. scando, to climb. Parrot; wood-pecker; toucan.
Gallinæ. Etym. gallina, a hen. Peacock ; pheasant; pigeon.
Grallæ. Etym. grallæ, stilts. Ostrich; stork; ibis ; flamingo.
Palmipedes. Etym. palma, the palm of the hand; pes, foot. Swan;
pelican ; gull.
THIRD Class. Reptiles.
Chelonia. Etpm. xelus, chelys, a tortoise. Tortoise ; turtle.
Sauria. Etym. gavpa, saura, a lizard. Crocodile ; alligator, chame-
leon; dragon ; pterdoctyle (Trepov, pteron, a wing: daktudos, dacty- .


APPENDIX.
211
lus, a finger); ichthyosaurus (exOvs, ichthys, a fish ; oavpa, saura, a
lizard); plesiosaurus (1) coloy, plesion, near to; oavpa, saura, a repo
tile); megalasaurus (ueyann, megale, great; oavpa, saur a, a reptile);
iguanadon.
Ophidia. Etym. opis, ophis, a serpent. Boa; viper.
Batrachia. Etym. Batpaxos, batrachos, a frog. Frog; salamander
proteus,
Fourth Class. Fishes.
Chondroplerygii. Etym. Xovdpos, chondros, gristle; atspuš, pterys, the
ray of a fin. Ray; sturgeon; shark ; lamprey; ammocete (appos,
ammos, sand ; KNTOS, cetos, a fish.)
Plectognathi. Etym, adekw, pleco, to join; yvabos, gnathos, the jaw.
Sun-fish ; trunk-fish.
Lophobranchi. Etym. dopos, lophos, a loop; Bpayxia, branchia, the
gills. Pipe-fish ; pegasus.
Melacopterygii. Etym. yalakos, malakos, soft ; #TEPVĚ, pteryx, the ray
of a fin. Salmon ; trout; cod; herring; remora.
Acanthopterygii. Etym. akavba, acantha, a thorn ; Trepuš, pteryx, the
ray of a fin. Perch ; sword-fish ; mackarel ; lophius piscatorius
(nopia, lophia, a pennant ; piscator, a fisher) ; chætodon rostratus
(xaite, chæte, hair ; odwv, odon, a tooth ; rostratus, beaked); zeus ci-
liaris (cilium, an eye-lash.)
DIVISION II.
MOLLUSCOUS ANIMALS.
Ist Class. Cephalopoda. Etym. Kepads, cephale, the head; roda, 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, vavrns, nautes, a sailor). Nautilus, (vavrns, nautes, a sailor.)
Ammonite, an extinct Cephalopode which inhabited a shell resembling
that of the Nautilus ; coiled like the horns of a ram or of the statues
of Jupiter Ammon; whence the name. Belemnites: also extinct
the shell is long, straight, and conical (BeNeuvov, 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. Trepov, pteron, a wing ; moda, poda,
feet ; having fins or processes resembling wings on each side of the mouth.


212
APPENDIX.
The Clio Borealis, which abounds in the North Seas, and is the prin-
cipal food of the whale.
3rd Class. Gasteropoda. Etym. yaotne, gaster, the stomach ; voda,
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 ; kepalm, cephale, the head.
Molluscous animals without a head.
The oyster; muscle.
5th Class. Brachiopoda. Etym. Bpaxlov, brachion, the arm; moda,
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 ; noda, poda,
the feet.
Balanus ; barnacle · anatifera, (anas, a duck, fero, to bring forth.)
DIVISION III.
ARTICULATA.
1st Class. Annelides, or Vermes. Etym. Annellus, a little ring ; vermia,
a worm.
Leech; sea-mouse ; earth-worm ; sand-worm ; tubicolæ, (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. apaxvus, 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 accord-
ng to the peculiarities of the wings.
Aptera (a, a, without ; atepov, pteron, a wing.) Centipede (having a
hundred feet); louse ; fea.
Coleoptera (Kodeos, coleos, a sheath or scabbard, arepov, a wing), insects
which have their wings protected by a cover, as the beetle, corn-
weevil. Orthoptera (opbos, orthos, straight, rrepov), as the locust,
grass-hopper. Hemiptera (plov, hemisu, half, *Tepov), insects which
have one half of their wings thick and coriaceous, and the other