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On the Relations of Man to the Lower Animals by Thomas H. Huxley

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This etext was prepared by Amy E. Zelmer.
This etext is based on^M


by Thomas H. Huxley

Multis videri poterit, majorem esso differentiam Simiae et Hominis, quam
diei et noctis; verum tamen hi, comparatione instituta inter summos
Europae Heroes et Hottentottos ad Caput bonae spei degentes,
difficillime sibi persuadebunt, has eosdem habere natales; vel si
virginem nobilem aulicam, maxime comtam et humanissimam, conferre
vellent cum homine sylvestri et sibi relicto, vix augurari possent,
hunc et illam ejusdem esse speciei.--'Linnaei Amoenitates Acad.

THE question of questions for mankind--the problem which underlies all
others, and is more deeply interesting than any other--is the
ascertainment of the place which Man occupies in nature and of his
relations to the universe of things. Whence our race has come; what are
the limits of our power over nature, and of nature's power over us; to
what goal we are tending; are the problems which present themselves
anew and with undiminished interest to every man born into the world.
Most of us, shrinking from the difficulties and dangers which beset the
seeker after original answers to these riddles, are contented to ignore
them altogether, or to smother the investigating spirit under the
featherbed of respected and respectable tradition. But, in every age,
one or two restless spirits, blessed with that constructive genius,
which can only build on a secure foundation, or cursed with the spirit
of mere scepticism, are unable to follow in the well-worn and
comfortable track of their forefathers and contemporaries, and
unmindful of thorns and stumbling-blocks, strike out into paths of their
own. The sceptics end in the infidelity which asserts the problem to
be insoluble, or in the atheism which denies the existence of any
orderly progress and governance of things: the men of genius propound
solutions which grow into systems of Theology or of Philosophy, or
veiled in musical language which suggests more than it asserts, take
the shape of the Poetry of an epoch.

Each such answer to the great question, invariably asserted by the
followers of its propounder, if not by himself, to be complete and
final, remains in high authority and esteem, it may be for one century,
or it may be for twenty: but, as invariably, Time proves each reply to
have been a mere approximation to the truth--tolerable chiefly on
account of the ignorance of those by whom it was accepted, and wholly
intolerable when tested by the larger knowledge of their successors.

In a well-worn metaphor, a parallel is drawn between the life of man and
the metamorphosis of the caterpillar into the butterfly; but the
comparison may be more just as well as more novel, if for its former
term we take the mental progress of the race. History shows that the
human mind, fed by constant accessions of knowledge, periodically grows
too large for its theoretical coverings, and bursts them asunder to
appear in new habiliments, as the feeding and growing grub, at
intervals, casts its too narrow skin and assumes another, itself but
temporary. Truly the imago state of Man seems to be terribly distant,
but every moult is a step gained, and of such there have been many.

Since the revival of learning, whereby the Western races of Europe were
enabled to enter upon that progress towards true knowledge, which was
commenced by the philosophers of Greece, but was almost arrested in
subsequent long ages of intellectual stagnation, or, at most, gyration,
the human larva has been feeding vigorously, and moulting in proportion.
A skin of some dimension was cast in the 16th century, and another
towards the end of the 18th, while, within the last fifty years, the
extraordinary growth of every department of physical science has spread
among us mental food of so nutritious and stimulating a character that a
new ecdysis seems imminent. But this is a process not unusually
accompanied by many throes and some sickness and debility, or, it may
be, by graver disturbances; so that every good citizen must feel bound
to facilitate the process, and even if he have nothing but a scalpel to
work withal, to ease the cracking integument to the best of his

In this duty lies my excuse for the publication of these essays. For it
will be admitted that some knowledge of man's position in the animate
world is an indispensable preliminary to the proper understanding of
his relations to the universe--and this again resolves itself, in the
long run, into an inquiry into the nature and the closeness of the ties
which connect him with those singular creatures whose history* has been
sketched in the preceding pages.

[footnote] * It will be understood that, in the preceding
Essay, I have selected for notice from the vast mass of
papers which have been written upon the man-like Apes, only
those which seem to me to be of special moment.

The importance of such an inquiry is indeed intuitively manifest
Brought face to face with these blurred copies of himself, the least
thoughtful of men is conscious of a certain shock, due perhaps, not so
much to disgust at the aspect of what looks like an insulting
caricature, as to the awakening of a sudden and profound mistrust of
time-honoured theories and strongly-rooted prejudices regarding his own
position in nature, and his relations to the under-world of life; while
that which remains a dim suspicion for the unthinking, becomes a vast
argument, fraught with the deepest consequences, for all who are
acquainted with the recent progress of the anatomical and physiological

I now propose briefly to unfold that argument, and to set forth, in a
form intelligible to those who possess no special acquaintance with
anatomical science, the chief facts upon which all conclusions
respecting the nature and the extent of the bonds which connect man with
the brute world must be based: I shall then indicate the one immediate
conclusion which, in my judgment, is justified by those facts, and I
shall finally discuss the bearing of that conclusion upon the
hypotheses which have been entertained respecting the Origin of Man.

The facts to which I would first direct the reader's attention, though
ignored by many of the professed instructors of the public mind, are
easy of demonstration and are universally agreed to by men of science;
while their significance is so great, that whoso has duly pondered over
them will, I think, find little to startle him in the other revelations
of Biology. I refer to those facts which have been made known by the
study of Development.

It is a truth of very wide, if not of universal, application, that every
living creature commences its existence under a form different from,
and simpler than, that which it eventually attains.

FIG. 12.--A. Egg of the Dog, with the vitelline membrane burst, so as
to give exit to the yolk, the germinal vesicle (a), and its included
spot (b). B. C. D. E F. Successive changes of the yolk indicated in
the text. After Bischoff.

The oak is a more complex thing than the little rudimentary plant
contained in the acorn; the caterpillar is more complex than the egg;
the butterfly than the caterpillar; and each of these beings, in
passing from its rudimentary to its perfect condition, runs through a
series of changes, the sum of which is called its Development. In the
higher animals these changes are extremely complicated; but, within the
last half century, the labours of such men as Von Baer, Rathke,
Reichert, Bischof, and Remak, have almost completely unravelled them, so
that the successive stages of development which are exhibited by a Dog,
for example, are now as well known to the embryologist as are the steps
of the metamorphosis of the silkworm moth to the school-boy. It will
be useful to consider with attention the nature and the order of the
stages of canine development, as an example of the process in the
higher animals generally.

The Dog, like all animals, save the very lowest (and further inquiries
may not improbably remove the apparent exception), commences its
existence as an egg: as a body which is, in every sense, as much an egg
as that of a hen, but is devoid of that accumulation of nutritive
matter which confers upon the bird's egg its exceptional size and
domestic utility; and wants the shell, which would not only be useless
to an animal incubated within the body of its parent, but would cut it
off from access to the source of that nutriment which the young
creature requires, but which the minute egg of the mammal does not
contain within itself.

The Dog's egg is, in fact, a little spheroidal bag (Fig. 12), formed of
a delicate transparent membrane called the 'vitelline membrane', and
about 1/130 to 1/120th of an inch in diameter. It contains a mass of
viscid nutritive matter--the 'yelk'--within which is inclosed a second
much more delicate spheroidal bag, called the 'germinal vesicle' (a).
In this, lastly, lies a more solid rounded body, termed the 'germinal
spot' (b).

The egg, or 'Ovum,' is originally formed within a gland, from which, in
due season, it becomes detached, and passes into the living chamber
fitted for its protection and maintenance during the protracted process
of gestation. Here, when subjected to the required conditions, this
minute and apparently insignificant particle of living matter becomes
animated by a new and mysterious activity. The germinal vesicle and
spot cease to be discernible (their precise fate being one of the yet
unsolved problems of embryology), but the yelk becomes
circumferentially indented, as if an invisible knife had been drawn
round it, and thus appears divided into two hemispheres (Fig. 12, C).

By the repetition of this process in various planes, these hemispheres
become subdivided, so that four segments are produced (D); and these,
in like manner, divide and subdivide again, until the whole yelk is
converted into a mass of granules, each of which consists of a minute
spheroid of yelk-substance, inclosing a central particle, the so-called
'nucleus' (F). Nature, by this process, has attained much the same
result as that at which a human artificer arrives by his operations in
a brickfield. She takes the rough plastic material of the yelk and
breaks it up into well-shaped tolerably even-sized masses, handy for
building up into any part of the living edifice.

FIG. 13.--Earliest rudiment of the Dog. B. Rudiment further advanced,
showing the foundations of the head, tail, and vertebral column. C.
The very young puppy, with attached ends of the yelk-sac and allantois,
and invested in the amnion.

Next, the mass of organic bricks, or 'cells' as they are technically
called, thus formed, acquires an orderly arrangement, becoming
converted into a hollow spheroid with double walls. Then, upon one
side of this spheroid, appears a thickening, and, by and bye, in the
centre of the area of thickening, a straight shallow groove (Fig. 13,
A) marks the central line of the edifice which is to be raised, or, in
other words, indicates the position of the middle line of the body of
the future dog. The substance bounding the groove on each side next
rises up into a fold, the rudiment of the side wall of that long
cavity, which will eventually lodge the spinal marrow and the brain;
and in the floor of this chamber appears a solid cellular cord, the
so-called 'notochord.' One end of the inclosed cavity dilates to form
the head (Fig. 13, B), the other remains narrow, and eventually becomes
the tail; the side walls of the body are fashioned out of the downward
continuation of the walls of the groove; and from them, by and bye,
grow out little buds which, by degrees, assume the shape of limbs.
Watching the fashioning process stage by stage, one is forcibly
reminded of the modeller in clay. Every part, every organ, is at
first, as it were, pinched up rudely, and sketched out in the rough;
then shaped more accurately; and only, at last, receives the touches
which stamp its final character.

Thus, at length, the young puppy assumes such a form as is shown in Fig.
13, C. In this condition it has a disproportionately large head, as
dissimilar to that of a dog as the bud-like limbs are unlike his legs.

The remains of the yelk, which have not yet been applied to the
nutrition and growth of the young animal, are contained in a sac
attached to the rudimentary intestine, and termed the yelk sac, or
'umbilical vesicle.' Two membranous bags, intended to subserve
respectively the protection and nutrition of the young creature, have
been developed from the skin and from the under and hinder surface of
the body; the former, the so-called 'amnion,' is a sac filled with
fluid, which invests the whole body of the embryo, and plays the part of
a sort of water-bed for it; the other, termed the 'allantois,' grows
out, loaded with blood-vessels, from the ventral region, and eventually
applying itself to the walls of the cavity, in which the developing
organism is contained, enables these vessels to become the channel by
which the stream of nutriment, required to supply the wants of the
offspring, is furnished to it by the parent.

The structure which is developed by the interlacement of the vessels of
the offspring with those of the parent, and by means of which the
former is enabled to receive nourishment and to get rid of effete
matters, is termed the 'Placenta.'

It would be tedious, and it is unnecessary for my present purpose, to
trace the process of development further; suffice it to say, that, by a
long and gradual series of changes, the rudiment here depicted and
described becomes a puppy, is born, and then, by still slower and less
perceptible steps, passes into the adult Dog.

There is not much apparent resemblance between a barndoor Fowl and the
Dog who protects the farm-yard. Nevertheless the student of
development finds, not only that the chick commences its existence as
an egg, primarily identical, in all essential respects, with that of
the Dog, but that the yelk of this egg undergoes division--that the
primitive groove arises, and that the contiguous parts of the germ are
fashioned, by precisely similar methods, into a young chick, which, at
one stage of its existence, is so like the nascent Dog, that ordinary
inspection would hardly distinguish the two.

The history of the development of any other vertebrate animal, Lizard,
Snake, Frog, or Fish, tells the same story. There is always, to begin
with, an egg having the same essential structure as that of the
Dog:--the yelk of that egg always undergoes division, or 'segmentation'
as it is often called: the ultimate products of that segmentation
constitute the building materials for the body of the young animal; and
this is built up round a primitive groove, in the floor of which a
notochord is developed. Furthermore, there is a period in which the
young of all these animals resemble one another, not merely in outward
form, but in all essentials of structure, so closely, that the
differences between them are inconsiderable, while, in their subsequent
course, they diverge more and more widely from one another. And it is a
general law, that, the more closely any animals resemble one another in
adult structure, the longer and the more intimately do their embryos
resemble one another: so that, for example, the embryos of a Snake and
of a Lizard remain like one another longer than do those of a Snake and
of a Bird; and the embryo of a Dog and of a Cat remain like one another
for a far longer period than do those of a Dog and a Bird; or of a Dog
and an Opossum; or even than those of a Dog and a Monkey.

Thus the study of development affords a clear test of closeness of
structural affinity, and one turns with impatience to inquire what
results are yielded by the study of the development of Man. Is he
something apart? Does he originate in a totally different way from Dog,
Bird, Frog, and Fish, thus justifying those who assert him to have no
place in nature and no real affinity with the lower world of animal
life? Or does he originate in a similar germ, pass through the same
slow and gradually progressive modifications,--depend on the same
contrivances for protection and nutrition, and finally enter the world
by the help of the same mechanism? The reply is not doubtful for a
moment, and has not been doubtful any time these thirty years. Without
question, the mode of origin and the early stages of the development of
man are identical with those of the animals immediately below him in the
scale:--without a doubt, in these respects, he is far nearer the Apes,
than the Apes are to the Dog.

The Human ovum is about l/125 of an inch in diameter, and might be
described in the same terms as that of the Dog, so that I need only
refer to the figure illustrative (14 A) of its structure. It leaves
the organ in which it is formed in a similar fashion and enters the
organic chamber prepared for its reception in the same way, the
conditions of its development being in all respects the same. It has
not yet been possible (and only by some rare chance can it ever be
possible) to study the human ovum in so early a developmental stage as
that of yelk division, but there is every reason to conclude that the
changes it undergoes are identical with those exhibited by the ova of
other vertebrated animals; for the formative materials of which the
rudimentary human body is composed, in the earliest conditions in which
it has been observed, are the same as those of other animals. Some of
these earliest stages are figured below, and, as will be seen, they are
strictly comparable to the very early states of the Dog; the marvellous
correspondence between the two which is kept up, even for some time, as
development advances, becoming apparent by the simple comparison of the
figures with those on page 249.

Fig. 14.--A. Human ovum (after Kolliker). a. germinal vesicle. b.
germinal spot. B. A very early condition of Man, with yelk-sac,
allantois, and amnion (original). C. A more advanced stage (after
Kolliker), compare Fig. 13, C.

Indeed, it is very long before the body of the young human being can be
readily discriminated from that of the young puppy; but, at a tolerably
early period, the two become distinguishable by the different form of
their adjuncts, the yelk-sac and the allantois. The former, in the
Dog, becomes long and spindle-shaped, while in Man it remains
spherical; the latter, in the Dog, attains an extremely large size, and
the vascular processes which are developed from it and eventually give
rise to the formation of the placenta (taking root, as it were, in the
parental organism, so as to draw nourishment therefrom, as the root of
a tree extracts it from the soil) are arranged in an encircling zone,
while in Man, the allantois remains comparatively small, and its
vascular rootlets are eventually restricted to one disk-like spot.
Hence, while the placenta of the Dog is like a girdle, that of Man has
the cake-like form, indicated by the name of the organ.

But, exactly in those respects in which the developing Man differs from
the Dog, he resembles the ape, which, like man, has a spheroidal
yelk-sac and a discoidal--sometimes partially lobed--placenta. So that
it is only quite in the later stages of development that the young
human being presents marked differences from the young ape, while the
latter departs as much from the dog in its development, as the man

Startling as the last assertion may appear to be, it is demonstrably
true, and it alone appears to me sufficient to place beyond all doubt
the structural unity of man with the rest of the animal world, and more
particularly and closely with the apes.

Thus, identical in the physical processes by which he
originates--identical in the early stages of his formation--identical
in the mode of his nutrition before and after birth, with the animals
which lie immediately below him in the scale--Man, if his adult and
perfect structure be compared with theirs, exhibits, as might be
expected, a marvellous likeness of organization. He resembles them as
they resemble one another--he differs from them as they differ from one
another.--And, though these differences and resemblances cannot be
weighed and measured, their value may be readily estimated; the scale
or standard of judgment, touching that value, being afforded and
expressed by the system of classification of animals now current among

A careful study of the resemblances and differences presented by animals
has, in fact, led naturalists to arrange them into groups, or
assemblages, all the members of each group presenting a certain amount
of definable resemblance, and the number of points of similarity being
smaller as the group is larger and 'vice versa'. Thus, all creatures
which agree only in presenting the few distinctive marks of animality
form the 'Kingdom' ANIMALIA. The numerous animals which agree only in
possessing the special characters of Vertebrates form one 'Sub-Kingdom'
of this Kingdom. Then the Sub-kingdom VERTEBRATA is subdivided into
the five 'Classes,' Fishes, Amphibians, Reptiles, Birds, and Mammals,
and these into smaller groups called 'Orders'; these into 'Families'
and 'Genera'; while the last are finally broken up into the smallest
assemblages, which are distinguished by the possession of constant,
not-sexual, characters. These ultimate groups are Species.

Every year tends to bring about a greater uniformity of opinion
throughout the zoological world as to the limits and characters of
these groups, great and small. At present, for example, no one has the
least doubt regarding the characters of the classes Mammalia, Aves, or
Reptilia; nor does the question arise whether any thoroughly well-known
animal should be placed in one class or the other. Again, there is a
very general agreement respecting the characters and limits of the
orders of Mammals, and as to the animals which are structurally
necessitated to take a place in one or another order.

No one doubts, for example, that the Sloth and the Ant-eater, the
Kangaroo and the Opossum, the Tiger and the Badger, the Tapir and the
Rhinoceros, are respectively members of the same orders. These
successive pairs of animals may, and some do, differ from one another
immensely, in such matters as the proportions and structure of their
limbs; the number of their dorsal and lumbar vertebrae; the adaptation
of their frames to climbing, leaping, or running; the number and form
of their teeth; and the characters of their skulls and of the contained
brain. But, with all these differences, they are so closely connected
in all the more important and fundamental characters of their
organization, and so distinctly separated by these same characters from
other animals, that zoologists find it necessary to group them together
as members of one order. And if any new animal were discovered, and
were found to present no greater difference from the Kangaroo and the
Opossum, for example, than these animals do from one another, the
zoologist would not only be logically compelled to rank it in the same
order with these, but he would not think of doing otherwise.

Bearing this obvious course of zoological reasoning in mind, let us
endeavour for a moment to disconnect our thinking selves from the mask
of humanity; let us imagine ourselves scientific Saturnians, if you
will, fairly acquainted with such animals as now inhabit the Earth, and
employed in discussing the relations they bear to a new and singular
'erect and featherless biped,' which some enterprising traveller,
overcoming the difficulties of space and gravitation, has brought from
that distant planet for our inspection, well preserved, may be, in a
cask of rum. We should all, at once, agree upon placing him among the
mammalian vertebrates; and his lower jaw, his molars, and his brain,
would leave no room for doubting the systematic position of the new
genus among those mammals, whose young are nourished during gestation
by means of a placenta, or what are called the 'placental mammals.'

Further, the most superficial study would at once convince us that,
among the orders of placental mammals, neither the Whales, nor the
hoofed creatures, nor the Sloths and Ant-eaters, nor the carnivorous
Cats, Dogs, and Bears, still less the Rodent Rats and Rabbits, or the
Insectivorous Moles and Hedgehogs, or the Bats, could claim our 'Homo',
as one of themselves.

There would remain then, but one order for comparison, that of the Apes
(using that word in its broadest sense), and the question for
discussion would narrow itself to this--is Man so different from any of
these Apes that he must form an order by himself? Or does he differ
less from them than they differ from one another, and hence must take
his place in the same order with them?

Being happily free from all real, or imaginary, personal interest in the
results of the inquiry thus set afoot, we should proceed to weigh the
arguments on one side and on the other, with as much judicial calmness
as if the question related to a new Opossum. We should endeavour to
ascertain, without seeking either to magnify or diminish them, all the
characters by which our new Mammal differed from the Apes; and if we
found that these were of less structural value, than those which
distinguish certain members of the Ape order from others universally
admitted to be of the same order, we should undoubtedly place the newly
discovered tellurian genus with them.

I now proceed to detail the facts which seem to me to leave us no choice
but to adopt the last mentioned course.

It is quite certain that the Ape which most nearly approaches man, in
the totality of its organization, is either the Chimpanzee or the
Gorilla; and as it makes no practical difference, for the purposes of
my present argument, which is selected for comparison, on the one hand,
with Man, and on the other hand, with the rest of the Primates,* I shall
select the latter (so far as its organization is known)--as a brute now
so celebrated in prose and verse, that all must have heard of him, and
have formed some conception of his appearance. I shall take up as many
of the most important points of difference between man and this
remarkable creature, as the space at my disposal will allow me to
discuss, and the necessities of the argument demand; and I shall
inquire into the value and magnitude of these differences, when placed
side by side with those which separate the Gorilla from other animals
of the same order.

[Footnote] *We are not at present thoroughly acquainted with
the brain of the Gorilla, and therefore, in discussing
cerebral characters, I shall take that of the Chimpanzee as
my highest term among the Apes.

In the general proportions of the body and limbs there is a remarkable
difference between the Gorilla and Man, which at once strikes the eye.
The Gorilla's brain-case is smaller, its trunk larger, its lower limbs
shorter, its upper limbs longer in proportion than those of Man.

I find that the vertebral column of a full-grown Gorilla, in the Museum
of the Royal College of Surgeons, measures 27 inches along its anterior
curvature, from the upper edge of the atlas, or first vertebra of the
neck, to the lower extremity of the sacrum; that the arm, without the
hand, is 31-1/2 inches long; that the leg, without the foot, is 26-1/2
inches long; that the hand is 9-3/4 inches long; the foot 11-1/4 inches

In other words, taking the length of the spinal column as 100, the arm
equals 115, the leg 96, the hand 36, and the foot 41.

In the skeleton of a male Bosjesman, in the same collection, the
proportions, by the same measurement, to the spinal column, taken as
100, are--the arm 78, the leg 110, the hand 26, and the foot 32. In a
woman of the same race the arm is 83, and the leg 120, the hand and
foot remaining the same. In a European skeleton I find the arm to be
80, the leg 117, the hand 26, the foot 35.

Thus the leg is not so different as it looks at first sight, in its
proportion to the spine in the Gorilla and in the Man--being very
slightly shorter than the spine in the former, and between 1/10 and 1/5
longer than the spine in the latter. The foot is longer and the hand
much longer in the Gorilla; but the great difference is caused by the
arms, which are very much longer than the spine in the Gorilla, very
much shorter than the spine in the Man.

The question now arises how are the other Apes related to the Gorilla in
these respects--taking the length of the spine, measured in the same
way, at 100. In an adult Chimpanzee, the arm is only 96, the leg 90,
the hand 43, the foot 39--so that the hand and the leg depart more from
the human proportion and the arm less, while the foot is about the same
as in the Gorilla.

In the Orang, the arms are very much longer than in the Gorilla (122),
while the legs are shorter (88); the foot is longer than the hand (52
and 48), and both are much longer in proportion to the spine.

In the other man-like Apes again, the Gibbons, these proportions are
still further altered; the length of the arms being to that of the
spinal column as 19 to 11; while the legs are also a third longer than
the spinal column, so as to be longer than in Man, instead of shorter.
The hand is half as long as the spinal column, and the foot, shorter
than the hand, is about 5/11ths of the length of the spinal column.

Thus 'Hylobates' is as much longer in the arms than the Gorilla, as the
Gorilla is longer in the arms than Man; while, on the other hand, it is
as much longer in the legs than the Man, as the Man is longer in the
legs than the Gorilla, so that it contains within itself the extremest
deviations from the average length of both pairs of limbs (See the
illustration on page 196).

The Mandrill presents a middle condition, the arms and legs being nearly
equal in length, and both being shorter than the spinal column; while
hand and foot have nearly the same proportions to one another and to
the spine, as in Man.

In the Spider monkey ('Ateles') the leg is longer than the spine, and
the arm than the leg; and, finally, in that remarkable Lemurine form,
the Indri ('Lichanotus'), the leg is about as long as the spinal
column, while the arm is not more than 11/18 of its length; the hand
having rather less and the foot rather more, than one-third the length
of the spinal column.

These examples might be greatly multiplied, but they suffice to show
that, in whatever proportion of its limbs the Gorilla differs from Man,
the other Apes depart still more widely from the Gorilla and that,
consequently, such differences of proportion can have no ordinal value.

We may next consider the differences presented by the trunk, consisting
of the vertebral column, or backbone, and the ribs and pelvis, or bony
hip-basin, which are connected with it, in Man and in the Gorilla

In Man, in consequence partly of the disposition of the articular
surfaces of the vertebrae, and largely of the elastic tension of some
of the fibrous bands, or ligaments, which connect these vertebrae
together, the spinal column, as a whole, has an elegant S-like
curvature, being convex forwards in the neck, concave in the back,
convex in the loins, or lumbar region, and concave again in the sacral
region; an arrangement which gives much elasticity to the whole
backbone, and diminishes the jar communicated to the spine, and through
it to the head, by locomotion in the erect position.

Furthermore, under ordinary circumstances, Man has seven vertebrae in
his neck, which are called 'cervical'; twelve succeed these, bearing
ribs and forming the upper part of the back, whence they are termed
'dorsal'; five lie in the loins, bearing no distinct, or free, ribs, and
are called 'lumbar'; five, united together into a great bone, excavated
in front, solidly wedged in between the hip bones, to form the back of
the pelvis, and known by the name of the 'sacrum', succeed these; and
finally, three or four little more or less movable bones, so small as to
be insignificant, constitute the 'coccyx' or rudimentary tail.

In the Gorilla, the vertebral column is similarly divided into cervical,
dorsal, lumbar, sacral, and coccygeal vertebrae, and the total number
of cervical and dorsal vertebrae, taken together, is the same as in
Man; but the development of a pair of ribs to the first lumbar vertebra,
which is an exceptional occurrence in Man, is the rule in the Gorilla;
and hence, as lumbar are distinguished from dorsal vertebrae only by
the presence or absence of free ribs, the seventeen "dorso-lumbar"
vertebrae of the Gorilla are divided into thirteen dorsal and four
lumbar, while in Man they are twelve dorsal and five lumbar.

FIG. 15.--Front and side views of the bony pelvis of Man, the Gorilla
and Gibbon: reduced from drawings made from nature, of the same
absolute length, by Mr. Waterhouse Hawkins.

Not only, however, does Man occasionally possess thirteen pair of ribs,*
but the Gorilla sometimes has fourteen pairs, while an Orang-Utan
skeleton in the Museum of the Royal College of Surgeons has twelve
dorsal and five lumbar vertebrae, as in Man. Cuvier notes the same
number in a 'Hylobates'. On the other hand, among the lower Apes, many
possess twelve dorsal and six or seven lumbar vertebrae; the
Douroucouli has fourteen dorsal and eight lumbar, and a Lemur ('Stenops
tardigradus') has fifteen dorsal and nine lumbar vertebrae.

[Footnote]* "More than once," says Peter Camper, "have I met
with more than six lumbar vertebrae in man.... Once I
found thirteen ribs and four lumbar vertebrae." Fallopius
noted thirteen pair of ribs and only four lumbar vertebrae;
and Eustachius once found eleven dorsal vertebrae and six
lumbar vertebrae.--'Oeuvres de Pierre Camper', T. 1, p.
42. As Tyson states, his 'Pygmie' had thirteen pair of ribs
and five lumbar vertebrae. The question of the curves of
the spinal column in the Apes requires further

The vertebral column of the Gorilla, as a whole, differs from that of
Man in the less marked character of its curves, especially in the
slighter convexity of the lumbar region. Nevertheless, the curves are
present, and are quite obvious in young skeletons of the Gorilla and
Chimpanzee which have been prepared without removal of the ligaments.
In young Orangs similarly preserved, on the other hand, the spinal
column is either straight, or even concave forwards, throughout the
lumbar region.

Whether we take these characters then, or such minor ones as those which
are derivable from the proportional length of the spines of the
cervical vertebrae, and the like, there is no doubt whatsoever as to
the marked difference between Man and the Gorilla; but there is as
little, that equally marked differences, of the very same order, obtain
between the Gorilla and the lower Apes.

The Pelvis, or bony girdle of the hips, of Man is a strikingly human
part of his organization; the expanded haunch bones affording support
for his viscera during his habitually erect posture, and giving space
for the attachment of the great muscles which enable him to assume and
to preserve that attitude. In these respects the pelvis of the Gorilla
differs very considerably from his (Fig. 15). But go no lower than the
Gibbon, and see how vastly more he differs from the Gorilla than the
latter does from Man, even in this structure. Look at the flat, narrow
haunch bones--the long and narrow passage--the coarse, outwardly curved,
ischiatic prominences on which the Gibbon habitually rests, and which
are coated by the so-called "callosities," dense patches of skin,
wholly absent in the Gorilla, in the Chimpanzee, and in the Orang, as
in Man!

In the lower Monkeys and in the Lemurs the difference becomes more
striking still, the pelvis acquiring an altogether quadrupedal

But now let us turn to a nobler and more characteristic organ--that by
which the human frame seems to be, and indeed is, so strongly
distinguished from all others,--I mean the skull. The differences
between a Gorilla's skull and a Man's are truly immense (Fig. 16). In
the former, the face, formed largely by the massive jaw-bones,
predominates over the brain case, or cranium proper: in the latter, the
proportions of the two are reversed. In the Man, the occipital
foramen, through which passes the great nervous cord connecting the
brain with the nerves of the body, is placed just behind the centre of
the base of the skull, which thus becomes evenly balanced in the erect
posture; in the Gorilla, it lies in the posterior third of that base.
In the Man, the surface of the skull is comparatively smooth, and the
supraciliary ridges or brow prominences usually project but
little--while, in the Gorilla, vast crests are developed upon the
skull, and the brow ridges overhang, the cavernous orbits, like great

Sections of the skulls, however, show that some of the apparent defects
of the Gorilla's cranium arise, in fact, not so much from deficiency of
brain case as from excessive development of the parts of the face. The
cranial cavity is not ill-shaped, and the forehead is not truly
flattened or very retreating, its really well-formed curve being simply
disguised by the mass of bone which is built up against it (Fig. 16).

But the roofs of the orbits rise more obliquely into the cranial cavity,
thus diminishing the space for the lower part of the anterior lobes of
the brain, and the absolute capacity of the cranium is far less than
that of Man. So far as I am aware, no human cranium belonging to an
adult man has yet been observed with a less cubical capacity than 62
cubic inches, the smallest cranium observed in any race of men by
Morton, measuring 63 cubic inches; while, on the other hand, the most
capacious Gorilla skull yet measured has a content of not more than
34-1/2 cubic inches. Let us assume, for simplicity's sake, that the
lowest Man's skull has twice the capacity of that of the highest

[Footnote] *It has been affirmed that Hindoo crania
sometimes contain as little as 27 ounces of water, which
would give a capacity of about 46cubic inches. The minimum
capacity which I have assumed above, however, is based upon
the valuable tables published by Professor R. Wagner in
his "Vorstudien zu einer wissenschaftlichen Morphologie und
Physiologie des menschlichen Gehirns." As the result of the
careful weighing of more than 900 human brains, Professor
Wagner states that one-half weighed between 1200 and 1400
grammes, and that about two-ninths, consisting for the most
part of male brains, exceed 1400 grammes. The lightest
brain of an adult male, with sound mental faculties,
recorded by Wagner, weighed 1020 grammes. As a gramme
equals 15.4 grains, and a cubic inch of water contains 252.4
grains, this is equivalent to 62 cubic inches of water; so
that as brain is heavier than water, we are perfectly safe
against erring on the side of diminution in taking this as
the smallest capacity of any adult male human brain. The
only adult male brain, weighing as little as 970 grammes,
is that of an idiot; but the brain of an adult woman,
against the soundness of whose faculties nothing appears,
weighed as little as 907 grammes (55.3 cubic inches of
water); and Reid gives an adult female brain of still
smaller capacity. The heaviest brain (1872 grammes, or
about 115 cubic inches) was, however, that of a woman; next
to it comes the brain of Cuvier (1861 grammes), then Byron
(1807 grammes), and then an insane person (1783 grammes).
The lightest adult brain recorded (720 grammes) was that of
an idiotic female. The brains of five children, four years
old, weighed between 1275 and 992 grammes. So that it may
be safely said, that an average European child of four
years old has a brain twice as large as that of an adult

No doubt, this is a very striking difference, but it loses much of its
apparent systematic value, when viewed by the light of certain other
equally indubitable facts respecting cranial capacities.

The first of these is, that the difference in the volume of the cranial
cavity of different races of mankind is far greater, absolutely, than
that between the lowest Man and the highest Ape, while, relatively, it
is about the same. For the largest human skull measured by Morton
contained 114 cubic inches, that is to say, had very nearly double the
capacity of the smallest; while its absolute preponderance, of 52 cubic
inches--is far greater than that by which the lowest adult male human
cranium surpasses the largest of the Gorillas (62 - 34-1/2 = 27-1/2).
Secondly, the adult crania of Gorillas which have as yet been measured
differ among themselves by nearly one-third, the maximum capacity being
34.5 cubic inches, the minimum 24 cubic inches; and, thirdly, after
making all due allowance for difference of size, the cranial capacities
of some of the lower Apes fall nearly as much, relatively, below those
of the higher Apes as the latter fall below Man.

Thus, even in the important matter of cranial capacity, Men differ more
widely from one another than they do from the Apes; while the lowest
Apes differ as much, in proportion, from the highest, as the latter
does from Man. The last proposition is still better illustrated by the
study of the modifications which other parts of the cranium undergo in
the Simian series.

It is the large proportional size of the facial bones and the great
projection of the jaws which confers upon the Gorilla's skull its small
facial angle and brutal character.

FIG. 16.--Sections of the skulls of Man and various Apes, drawn so as to
give the cerebral cavity the same length in each case, thereby
displaying the varying proportions of the facial bones. The line 'b'
indicates the plane of the tentorium, which separates the cerebrum from
the cerebellum; 'd', the axis of the occipital outlet of the skull. The
extent of cerebral cavity behind 'c', which is a perpendicular erected
on 'b' at the point where the tentorium is attached posteriorly,
indicates the degree to which the cerebrum overlaps the cerebellum--the
space occupied by which is roughly indicated by the dark shading. In
comparing these diagrams, it must be recollected, that figures on so
small a scale as these simply exemplify the statements in the text, the
proof of which is to be found in the objects themselves.

But if we consider the proportional size of the facial bones to the
skull proper only, the little 'Chrysothrix' (Fig. 16) differs very
widely from the Gorilla, and, in the same way, as Man does; while the
Baboons ('Cynocephalus', Fig. 16) exaggerate the gross proportions of
the muzzle of the great Anthropoid, so that its visage looks mild and
human by comparison with theirs. The difference between the Gorilla
and the Baboon is even greater than it appears at first sight; for the
great facial mass of the former is largely due to a downward development
of the jaws; an essentially human character, superadded upon that
almost purely forward, essentially brutal, development of the same
parts which characterizes the Baboon, and yet more remarkably
distinguishes the Lemur.

Similarly, the occipital foramen of 'Mycetes' (Fig. 16), and still more
of the Lemurs, is situated completely in the posterior face of the
skull, or as much further back than that of the Gorilla, as that of the
Gorilla is further back than that of Man; while, as if to render patent
the futility of the attempt to base any broad classificatory
distinction on such a character, the same group of Platyrhine, or
American monkeys, to which the Mycetes belongs, contains the
Chrysothrix, whose occipital foramen is situated far more forward than
in any other ape, and nearly approaches the position it holds in Man.

Again, the Orang's skull is as devoid of excessively developed
supraciliary prominences as a Man's, though some varieties exhibit
great crests elsewhere (See pp. 231, 232); and in some of the Cebine
apes and in the 'Chrysothrix', the cranium is as smooth and rounded as
that of Man himself.

What is true of these leading characteristics of the skull, holds good,
as may be imagined, of all minor features; so that for every constant
difference between the Gorilla's skull and the Man's, a similar
constant difference of the same order (that is to say, consisting in
excess or defect of the same quality) may be found between the
Gorilla's skull and that of some other ape. So that, for the skull, no
less than for the skeleton in general, the proposition holds good, that
the differences between Man and the Gorilla are of smaller value than
those between the Gorilla and some other Apes.

In connection with the skull, I may speak of the teeth--organs which
have a peculiar classificatory value, and whose resemblances and
differences of number, form, and succession, taken as a whole, are
usually regarded as more trustworthy indicators of affinity than any

FIG. 17.--Lateral views, of the same length, of the upper jaws of
various Primates. 'i', incisors; 'c', canines' 'pm', premolars; 'm',
molars. A line is drawn through the first molar of Man, 'Gorilla',
'Cynocephalus', and 'Cebus', and the grinding surface of the second
molar is shown in each, its anterior and internal angle being just
above the 'm' of 'm2'.

Man is provided with two sets of teeth--milk teeth and permanent teeth.
The former consist of four incisors, or cutting teeth; two canines, or
eyeteeth; and four molars, or grinders, in each jaw--making twenty in
all. The latter (Fig. 17) comprise four incisors, two canines, four
small grinders, called premolars or false molars, and six large
grinders, or true molars, in each jaw--making thirty-two in all. The
internal incisors are larger than the external pair, in the upper jaw,
smaller than the external pair, in the lower jaw. The crowns of the
upper molars exhibit four cusps, or blunt-pointed elevations, and a
ridge crosses the crown obliquely, from the inner, anterior cusp to the
outer, posterior cusp (Fig. 17 m2). The anterior lower molars have
five cusps, three external and two internal. The premolars have two
cusps, one internal and one external, of which the outer is the higher.

In all these respects the dentition of the Gorilla may be described in
the same terms as that of Man; but in other matters it exhibits many
and important differences (Fig. 17).

Thus the teeth of man constitute a regular and even series--without any
break and without any marked projection of one tooth above the level of
the rest; a peculiarity which, as Cuvier long ago showed, is shared by
no other mammal save one--as different a creature from man as can well
be imagined--namely, the long extinct 'Anoplotherium'. The teeth of the
Gorilla, on the contrary, exhibit a break, or interval, termed the
'diastema', in both jaws: in front of the eye-tooth, or between it and
the outer incisor, in the upper jaw; behind the eyetooth, or between it
and the front false molar, in the lower jaw. Into this break in the
series, in each jaw, fits the canine of the opposite jaw; the size of
the eye-tooth in the Gorilla being so great that it projects, like a
tusk, far beyond the general level of the other teeth. The roots of
the false molar teeth of the Gorilla, again, are more complex than in
Man, and the proportional size of the molars is different. The Gorilla
has the crown of the hindmost grinder of the lower jaw more complex,
and the order of eruption of the permanent teeth is different; the
permanent canines making their appearance before the second and third
molars in Man, and after them in the Gorilla.

Thus, while the teeth of the Gorilla closely resemble those of Man in
number, kind, and in the general pattern of their crowns, they exhibit
marked differences from those of Man in secondary respects, such as
relative size, number of fangs, and order of appearance.

But, if the teeth of the Gorilla be compared with those of an Ape, no
further removed from it than a 'Cynocephalus', or Baboon, it will be
found that differences and resemblances of the same order are easily
observable; but that many of the points in which the Gorilla resembles
Man are those in which it differs from the Baboon; while various
respects in which it differs from Man are exaggerated in the
'Cynocephalus'. The number and the nature of the teeth remain the same
in the Baboon as in the Gorilla and in Man. But the pattern of the
Baboon's upper molars is quite different from that described above
(Fig. 17), the canines are proportionally longer and more knife-like;
the anterior premolar in the lower jaw is specially modified; the
posterior molar of the lower jaw is still larger and more complex than
in the Gorilla.

Passing from the old-world Apes to those of the new world, we meet with
a change of much greater importance than any of these. In such a genus
as 'Cebus', for example (Fig. 17), it will be found that while in some
secondary points, such as the projection of the canines and the
diastema, the resemblance to the great ape is preserved; in other and
most important respects, the dentition is extremely different. Instead
of 20 teeth in the milk set, there are 24: instead of 32 teeth in the
permanent set, there are 36, the false molars being increased from eight
to twelve. And in form, the crowns of the molars are very unlike those
of the Gorilla, and differ far more widely from the human pattern.

The Marmosets, on the other hand, exhibit the same number of teeth as
Man and the Gorilla; but, notwithstanding this, their dentition is very
different, for they have four more false molars, like the other
American monkeys--but as they have four fewer true molars, the total
remains the same. And passing from the American apes to the Lemurs,
the dentition becomes still more completely and essentially different
from that of the Gorilla. The incisors begin to vary both in number
and in form. The molars acquire, more and more, a many-pointed,
insectivorous character, and in one Genus, the Aye-Aye ('Cheiromys'),
the canines disappear, and the teeth completely simulate those of a
Rodent (Fig. 17).

Hence it is obvious that, greatly as the dentition of the highest Ape
differs from that of Man, it differs far more widely from that of the
lower and lowest Apes.

Whatever part of the animal fabric--whatever series of muscles, whatever
viscera might be selected for comparison--the result would be the
same--the lower Apes and the Gorilla would differ more than the Gorilla
and the Man. I cannot attempt in this place to follow out all these
comparisons in detail, and indeed it is unnecessary I should do so. But
certain real, or supposed, structural distinctions between man and the
apes remain, upon which so much stress has been laid, that they require
careful consideration, in order that the true value may be assigned to
those which are real, and the emptiness of those which are fictitious
may be exposed. I refer to the characters of the hand, the foot, and
the brain.

Man has been defined as the only animal possessed of two hands
terminating his fore limbs, and of two feet ending his hind limbs,
while it has been said that all the apes possess four hands; and he has
been affirmed to differ fundamentally from all the apes in the
characters of his brain, which alone, it has been strangely asserted
and re-asserted, exhibits the structures known to anatomists as the
posterior lobe, the posterior cornu of the lateral ventricle, and the
hippocampus minor.

That the former proposition should have gained general acceptance is not
surprising--indeed, at first sight, appearances are much in its favour:
but, as for the second, one can only admire the surpassing courage of
its enunciator, seeing that it is an innovation which is not only
opposed to generally and justly accepted doctrines, but which is
directly negatived by the testimony of all original inquirers, who have
specially investigated the matter: and that it neither has been, nor
can be, supported by a single anatomical preparation. It would, in
fact, be unworthy of serious refutation, except for the general and
natural belief that deliberate and reiterated assertions must have some

Before we can discuss the first point with advantage we must consider
with some attention, and compare together, the structure of the human
hand and that of the human foot, so that we may have distinct and clear
ideas of what constitutes a hand and what a foot.

The external form of the human hand is familiar enough to every one. It
consists of a stout wrist followed by a broad palm, formed of flesh,
and tendons, and skin, binding together four bones, and dividing into
four long and flexible digits, or fingers, each of which bears on the
back of its last joint a broad and flattened nail. The longest cleft
between any two digits is rather less than half as long as the hand.
From the outer side of the base of the palm a stout digit goes off,
having only two joints instead of three; so short, that it only reaches
to a little beyond the middle of the first joint of the finger next it;
and further remarkable by its great mobility, in consequence of which
it can be directed outwards, almost at a right angle to the rest. This
digit is called the 'pollex,' or thumb; and, like the others, it bears a
flat nail upon the back of its terminal joint. In consequence of the
proportions and mobility of the thumb, it is what is termed
"opposable"; in other words, its extremity can, with the greatest ease,
be brought into contact with the extremities of any of the fingers; a
property upon which the possibility of our carrying into effect the
conceptions of the mind so largely depends.

The external form of the foot differs widely from that of the hand; and
yet, when closely compared, the two present some singular
resemblances. Thus the ankle corresponds in a manner with the wrist;
the sole with the palm; the toes with the fingers; the great toe with
the thumb. But the toes, or digits of the foot, are far shorter in
proportion than the digits of the hand, and are less moveable, the want
of mobility being most striking in the great toe--which, again, is very
much larger in proportion to the other toes than the thumb to the
fingers. In considering this point, however, it must not be forgotten
that the civilized great toe, confined and cramped from childhood
upwards, is seen to a great disadvantage, and that in uncivilized and
barefooted people it retains a great amount of mobility, and even some
sort of opposability. The Chinese boatmen are said to be able to pull
an oar; the artisans of Bengal to weave, and the Carajas to steal
fishhooks, by its help; though, after all, it must be recollected that
the structure of its joints and the arrangement of its bones,
necessarily render its prehensile action far less perfect than that of
the thumb.

But to gain a precise conception of the resemblances and differences of
the hand and foot, and of the distinctive characters of each, we must
look below the skin, and compare the bony framework and its motor
apparatus in each (Fig. 18).

FIG. 18-.-The skeleton of the Hand and Foot of Man reduced from Dr.
Carter's drawings in Gray's 'Anatomy.' The hand is drawn to a larger
scale than the foot. The line 'a a' in the hand indicates the boundary
between the carpus and the metacarpus; 'b b' that between the latter
and the proximal phalanges; 'c c' marks the ends of the distal
phalanges. The line "a' a'" in the foot indicates the boundary between
the tarsus and metatarsus; "b' b'" marks that between the metatarsus
and the proximal phalanges; and "c' c'" bounds the ends of the distal
phalanges; 'ca', the calcaneum; 'as', the astragalus; 'sc', the
scaphoid bone in the tarsus.

The skeleton of the hand exhibits, in the region which we term the
wrist, and which is technically called the 'carpus'--two rows of
closely fitted polygonal bones, four in each row, which are tolerably
equal in size. The bones of the first row with the bones of the
forearm, form the wrist joint, and are arranged side by side, no one
greatly exceeding or overlapping the rest.

The four bones of the second row of the carpus bear the four long bones
which support the palm of the hand. The fifth bone of the same
character is articulated in a much more free and moveable manner than
the others, with its carpal bone, and forms the base of the thumb.
These are called 'metacarpal' bones, and they carry the 'phalanges', or
bones of the digits, of which there are two in the thumb, and three in
each of the fingers.

The skeleton of the foot is very like that of the hand in some respects.
Thus there are three phalanges in each of the lesser toes, and only two
in the great toe, which answers to the thumb. There is a long bone,
termed 'metatarsal', answering to the metacarpal, for each digit; and
the 'tarsus', which corresponds with the carpus, presents four short
polygonal bones in a row, which correspond very closely with the four
carpal bones of the second row of the hand. In other respects the foot
differs very widely from the hand. Thus the great toe is the longest
digit but one; and its metatarsal is far less moveably articulated with
the tarsus, than the metacarpal of the thumb with the carpus. But a
far more important distinction lies in the fact that, instead of four
more tarsal bones there are only three; and, that these three are not
arranged side by side, or in one row. One of them, the 'os calcis' or
heel bone ('ca'), lies externally, and sends back the large projecting
heel; another, the 'astragalus' ('as'), rests on this by one face, and
by another, forms, with the bones of the leg, the ankle joint; while a
third face, directed forwards, is separated from the three inner tarsal
bones of the row next the metatarsus by a bone called the 'scaphoid'

Thus there is a fundamental difference in the structure of the foot and
the hand, observable when the carpus and the tarsus are contrasted; and
there are differences of degree noticeable when the proportions and the
mobility of the metacarpals and metatarsals, with their respective
digits, are compared together.

The same two classes of differences become obvious when the muscles of
the hand are compared with those of the foot.

Three principal sets of muscles, called "flexors," bend the fingers and
thumb, as in clenching the fist, and three sets--the extensors--extend
them, as in straightening the fingers. These muscles are all "long
muscles"; that is to say, the fleshy part of each, lying in and being
fixed to the bones of the arm, is, at the other end, continued into
tendons, or rounded cords, which pass into the hand, and are ultimately
fixed to the bones which are to be moved. Thus, when the fingers are
bent, the fleshy parts of the flexors of the fingers, placed in the arm,
contract, in virtue of their peculiar endowment as muscles; and pulling
the tendinous cords, connected with their ends, cause them to pull down
the bones of the fingers towards the palm.

Not only are the principal flexors of the fingers and of the thumb long
muscles, but they remain quite distinct from one another through their
whole length.

In the foot, there are also three principal flexor muscles of the digits
or toes, and three principal extensors; but one extensor and one flexor
are short muscles; that is to say, their fleshy parts are not situated
in the leg (which corresponds with the arm), but in the back and in the
sole of the foot--regions which correspond with the back and the palm of
the hand.

Again, the tendons of the long flexor of the toes, and of the long
flexor of the great toe, when they reach the sole of the foot, do not
remain distinct from one another, as the flexors in the palm of the
hand do, but they become united and commingled in a very curious
manner--while their united tendons receive an accessory muscle
connected with the heel-bone.

But perhaps the most absolutely distinctive character about the muscles
of the foot is the existence of what is termed the 'peronaeus longus',
a long muscle fixed to the outer bone of the leg, and sending its
tendon to the outer ankle, behind and below which it passes, and then
crosses the foot obliquely to be attached to the base of the great toe.
No muscle in the hand exactly corresponds with this, which is eminently
a foot muscle.

To resume--the foot of man is distinguished from his hand by the
following absolute anatomical differences:--

1. By the arrangement of the tarsal bones.

2. By having a short flexor and a short extensor muscle of the digits.

3. By possessing the muscle termed 'peronaeus longus'.

And if we desire to ascertain whether the terminal division of a limb,
in other Primates, is to be called a foot or a hand, it is by the
presence or absence of these characters that we must be guided, and not
by the mere proportions and greater or lesser mobility of the great toe,
which may vary indefinitely without any fundamental alteration in the
structure of the foot.

Keeping these considerations in mind, let us now turn to the limbs of
the Gorilla. The terminal division of the fore limb presents no
difficulty--bone for bone and muscle for muscle, are found to be
arranged essentially as in man, or with such minor differences as are
found as varieties in man. The Gorilla's hand is clumsier, heavier,
and has a thumb somewhat shorter in proportion than that of man; but no
one has ever doubted its being a true hand.

FIG 19.--Foot of Man, Gorilla, and Orang-Utan of the same absolute
length, to show the differences in proportion of each. Letters as in
Fig. 18. Reduced from original drawings by Mr. Waterhouse Hawkins.

At first sight, the termination of the hind limb of the Gorilla looks
very hand-like, and as it is still more so in many of the lower apes,
it is not wonderful that the appellation "Quadrumana," or four-handed
creatures, adopted from the older anatomists* by Blumenbach, and
unfortunately rendered current by Cuvier, should have gained such wide
acceptance as a name for the Simian group. But the most cursory
anatomical investigation at once proves that the resemblance of the
so-called "hind hand" to a true hand, is only skin deep, and that, in
all essential respects, the hind limb of the Gorilla is as truly
terminated by a foot as that of man. The tarsal bones, in all important
circumstances of number, disposition, and form, resemble those of man
(Fig. 19). The metatarsals and digits, on the other hand, are
proportionally longer and more slender, while the great toe is not only
proportionally shorter and weaker, but its metatarsal bone is united by
a more moveable joint with the tarsus. At the same time, the foot is
set more obliquely upon the leg than in man.

{Footnote} *In speaking of the foot of his "Pygmie," Tyson remarks, p.
13:-- "But this part in the formation and in its function too, being
liker a Hand than a Foot: for the distinguishing this sort of animals
from others, I have thought whether it might not be reckoned and called
rather Quadru-manus than Quadrupes, 'i.e.' a four-handed rather than a
four-footed animal."

As this passage was published in 1699, M. I. G. St. Hilaire is clearly
in error in ascribing the invention of the term "quadrumanous" to
Buffon, though "himanous" may belong to him. Tyson uses "Quadrumanus"
in several places, as at p. 91.... "Our 'Pygmie' is no Man, nor yet
the 'common Ape', but a sort of 'Animal' between both; and though a
'Biped', yet of the 'Quadrumanus'-kind: though some 'Men' too have been
observed to use their 'Feet' like 'Hands', as I have seen several."

As to the muscles, there is a short flexor, a short extensor, and a
'peronaeus longus', while the tendons of the long flexors of the great
toe and of the other toes are united together and with an accessory
fleshy bundle.

The hind limb of the Gorilla, therefore, ends in a true foot, with a
very moveable great toe. It is a prehensile foot, indeed, but is in no
sense a hand: it is a foot which differs from that of man not in any
fundamental character, but in mere proportions, in the degree of
mobility, and in the secondary arrangement of its parts.

It must not be supposed, however, because I speak of these differences
as not fundamental, that I wish to underrate their value. They are
important enough in their way, the structure of the foot being in
strict correlation with that of the rest of the organism in each case.
Nor can it be doubted that the greater division of physiological labour
in Man, so that the function of support is thrown wholly on the leg and
foot, is an advance in organization of very great moment to him; but,
after all, regarded anatomically, the resemblances between the foot of
Man and the foot of the Gorilla are far more striking and important than
the differences.

I have dwelt upon this point at length, because it is one regarding
which much delusion prevails; but I might have passed it over without
detriment to my argument, which only requires me to show that, be the
differences between the hand and foot of Man and those of the Gorilla
what they may--the differences between those of the Gorilla, and those
of the lower Apes are much greater.

It is not necessary to descend lower in the scale than the Orang for
conclusive evidence on this head.

The thumb of the Orang differs more from that of the Gorilla than the
thumb of the Gorilla differs from that of Man, not only by its
shortness, but by the absence of any special long flexor muscle. The
carpus of the Orang, like that of most lower apes, contains nine bones,
while in the Gorilla, as in Man and the Chimpanzee, there are only

The Orang's foot (Fig. 19) is still more aberrant; its very long toes
and short tarsus, short great toe, short and raised heel, great
obliquity of articulation in the leg, and absence of a long flexor
tendon to the great toe, separating it far more widely from the foot of
the Gorilla than the latter is separated from that of Man.

But, in some of the lower apes, the hand and foot diverge still more
from those of the Gorilla, than they do in the Orang. The thumb ceases
to be opposable in the American monkeys; is reduced to a mere rudiment
covered by the skin in the Spider Monkey; and is directed forwards and
armed with a curved claw like the other digits, in the Marmosets--so
that, in all these cases, there can be no doubt but that the hand is
more different from that of the Gorilla than the Gorilla's hand is from

And as to the foot, the great toe of the Marmoset is still more
insignificant in proportion than that of the Orang--while in the Lemurs
it is very large, and as completely thumb-like and opposable as in the
Gorilla--but in these animals the second toe is often irregularly
modified, and in some species the two principal bones of the tarsus,
the 'astragalus' and the 'os calcis', are so immensely elongated as to
render the foot, so far, totally unlike that of any other mammal.

So with regard to the muscles. The short flexor of the toes of the
Gorilla differs from that of Man by the circumstance that one slip of
the muscle is attached, not to the heel bone, but to the tendons of the
long flexors. The lower Apes depart from the Gorilla by an exaggeration
of the same character, two, three, or more, slips becoming fixed to the
long flexor tendons--or by a multiplication of the slips.--Again, the
Gorilla differs slightly from Man in the mode of interlacing of the
long flexor tendons: and the lower apes differ from the Gorilla in
exhibiting yet other, sometimes very complex, arrangements of the same
parts, and occasionally in the absence of the accessory fleshy bundle.

Throughout all these modifications it must be recollected that the foot
loses no one of its essential characters. Every Monkey and Lemur
exhibits the characteristic arrangement of tarsal bones, possesses a
short flexor and short extensor muscle, and a 'peronaeus longus'.
Varied as the proportions and appearance of the organ may be, the
terminal division of the hind limb remains, in plan and principle of
construction, a foot, and never, in those respects, can be confounded
with a hand.

Hardly any part of the bodily frame, then, could be found better
calculated to illustrate the truth that the structural differences
between Man and the highest Ape are of less value than those between
the highest and the lower Apes, than the hand or the foot, and yet,
perhaps, there is one organ the study of which enforces the same
conclusion in a still more striking manner--and that is the Brain.

But before entering upon the precise question of the amount of
difference between the Ape's brain and that of Man, it is necessary
that we should clearly understand what constitutes a great, and what a
small difference in cerebral structure; and we shall be best enabled to
do this by a brief study of the chief modifications which the brain
exhibits in the series of vertebrate animals.

The brain of a fish is very small, compared with the spinal cord into
which it is continued, and with the nerves which come off from it: of
the segments of which it is composed--the olfactory lobes, the cerebral
hemisphere, and the succeeding divisions--no one predominates so much
over the rest as to obscure or cover them; and the so-called optic lobes
are, frequently, the largest masses of all. In Reptiles, the mass of
the brain, relatively to the spinal cord, increases and the cerebral
hemispheres begin to predominate over the other parts; while in Birds
this predominance is still more marked. The brain of the lowest
Mammals, such as the duck-billed Platypus and the Opossums and
Kangaroos, exhibits a still more definite advance in the same
direction. The cerebral hemispheres have now so much increased in size
as, more or less, to hide the representatives of the optic lobes, which
remain comparatively small, so that the brain of a Marsupial is
extremely different from that of a Bird, Reptile, or Fish. A step
higher in the scale, among the placental Mammals, the structure of the
brain acquires a vast modification--not that it appears much altered
externally, in a Rat or in a Rabbit, from what it is in a
Marsupial--nor that the proportions of its parts are much changed, but
an apparently new structure is found between the cerebral hemispheres,
connecting them together, as what is called the 'great commissure' or
'corpus callosum.' The subject requires careful re-investigation, but
if the currently received statements are correct, the appearance of the
'corpus callosum' in the placental mammals is the greatest and most
sudden modification exhibited by the brain in the whole series of
vertebrated animals--it is the greatest leap anywhere made by Nature in
her brain work. For the two halves of the brain being once thus knit
together, the progress of cerebral complexity is traceable through a
complete series of steps from the lowest Rodent, or Insectivore, to
Man; and that complexity consists, chiefly, in the disproportionate
development of the cerebral hemispheres and of the cerebellum, but
especially of the former, in respect to the other parts of the brain.

In the lower placental mammals, the cerebral hemispheres leave the
proper upper and posterior face of the cerebellum completely visible,
when the brain is viewed from above; but, in the higher forms, the
hinder part of each hemisphere, separated only by the tentorium (p.
281) from the anterior face of the cerebellum, inclines backwards and
downwards, and grows out, as the so-called "posterior lobe," so as at
length to overlap and hide the cerebellum. In all Mammals, each
cerebral hemisphere contains a cavity which is termed the 'ventricle,'
and as this ventricle is prolonged, on the one hand, forwards, and on
the other downwards, into the substance of the hemisphere, it is said
to have two horns or 'cornua, an 'anterior cornu,' and a 'descending
cornu.' When the posterior lobe is well developed, a third prolongation
of the ventricular cavity extends into it, and is called the "posterior

In the lower and smaller forms of placental Mammals the surface of the
cerebral hemispheres is either smooth or evenly rounded, or exhibits a
very few grooves, which are technically termed 'sulci,'separating
ridges or 'convolutions' of the substance of the brain; and the smaller
species of all orders tend to a similar smoothness of brain. But, in
the higher orders, and especially the larger members of these orders,
the grooves, or sulci, become extremely numerous, and the intermediate
convolutions proportionately more complicated in their meanderings,
until, in the Elephant, the Porpoise, the higher Apes, and Man, the
cerebral surface appears a perfect labyrinth of tortuous foldings.

Where a posterior lobe exists and presents its customary cavity--the
posterior cornu--it commonly happens that a particular sulcus appears
upon the inner and under surface of the lobe, parallel with and beneath
the floor of the cornu--which is, as it were, arched over the roof of
the sulcus. It is as if the groove had been formed by indenting the
floor of the posterior horn from without with a blunt instrument, so
that the floor should rise as a convex eminence. Now this eminence is
what has been termed the 'Hippocampus minor;' the 'Hippocampus major'
being a larger eminence in the floor of the descending cornu. What may
be the functional importance of either of these structures we know not.

As if to demonstrate, by a striking example, the impossibility of
erecting any cerebral barrier between man and the apes, Nature has
provided us, in the latter animals, with an almost complete series of
gradations from brains little higher than that of a Rodent, to brains
little lower than that of Man. And it is a remarkable circumstance
that though, so far as our present knowledge extends, there 'is' one
true structural break in the series of forms of Simian brains, this
hiatus does not lie between Man and the man-like apes, but between the
lower and the lowest Simians; or, in other words, between the old and
new world apes and monkeys, and the Lemurs. Every Lemur which has yet
been examined, in fact, has its cerebellum partially visible from
above, and its posterior lobe, with the contained posterior cornu and
hippocampus minor, more or less rudimentary. Every Marmoset, American
monkey, old-world monkey, Baboon, or Man-like ape, on the contrary, has
its cerebellum entirely hidden, posteriorly, by the cerebral lobes, and
possesses a large posterior cornu, with a well-developed hippocampus

FIG. 20.--Drawings of the internal casts of a Man's and of a
Chimpanzee's skull, of the same absolute length, and placed in
corresponding positions. 'A'. Cerebrum; 'B'. Cerebellum. The former
drawing is taken from a cast in the Museum of the Royal College of
Surgeons, the latter from the photograph of the cast of a Chimpanzee's
skull, which illustrates the paper by Mr. Marshall 'On the Brain of the
Chimpanzee' in the 'Natural History Review' for July, 1861. The sharper
definition of the lower edge of the cast of the cerebral chamber in the
Chimpanzee arises from the circumstance that the tentorium remained in
that skull and not in the Man's. The cast more accurately represents
the brain in Chimpanzee than in the Man; and the great backward
projection of the posterior lobes of the cerebrum of the former, beyond
the cerebellum, is conspicuous.

In many of these creatures, such as the Saimiri ('Chrysothrix'), the
cerebral lobes overlap and extend much further behind the cerebellum,
in proportion, than they do in man (Fig. 16)--and it is quite certain
that, in all, the cerebellum is completely covered behind, by
well-developed posterior lobes. The fact can be verified by every one
who possesses the skull of any old or new world monkey. For, inasmuch
as the brain in all mammals completely fills the cranial cavity, it is
obvious that a cast of the interior of the skull will reproduce the
general form of the brain, at any rate with such minute and, for the
present purpose, utterly unimportant differences as may result from the
absence of the enveloping membranes of the brain in the dry skull. But
if such a cast be made in plaster, and compared with a similar cast of
the interior of a human skull, it will be obvious that the cast of the
cerebral chamber, representing the cerebrum of the ape, as completely
covers over and overlaps the cast of the cerebellar chamber,
representing the cerebellum, as it does in the man (Fig. 20). A
careless observer, forgetting that a soft structure like the brain
loses its proper shape the moment it is taken out of the skull, may
indeed mistake the uncovered condition of the cerebellum of an extracted
and distorted brain for the natural relations of the parts; but his
error must become patent even to himself if he try to replace the brain
within the cranial chamber. To suppose that the cerebellum of an ape is
naturally uncovered behind is a miscomprehension comparable only to
that of one who should imagine that a man's lungs always occupy but a
small portion of the thoracic cavity--because they do so when the chest
is opened, and their elasticity is no longer neutralized by the
pressure of the air.

And the error is the less excusable, as it must become apparent to every
one who examines a section of the skull of any ape above a Lemur,
without taking the trouble to make a cast of it. For there is a very
marked groove in every such skull, as in the human skull--which
indicates the line of attachment of what is termed the 'tentorium'--a
sort of parchment-like shelf, or partition, which, in the recent state,
is interposed between the cerebrum and cerebellum, and prevents the
former from pressing upon the latter. (See Fig. 16.)

This groove, therefore, indicates the line of separation between that
part of the cranial cavity which contains the cerebrum, and that which
contains the cerebellum; and as the brain exactly fills the cavity of
the skull, it is obvious that the relations of these two parts of the
cranial cavity at once informs us of the relations of their contents.
Now in man, in all the old-world, and in all the new-world Simiae, with
one exception, when the face is directed forwards, this line of
attachment of the tentorium, or impression for the lateral sinus, as it
is technically called, is nearly horizontal, and the cerebral chamber
invariably overlaps or projects behind the cerebellar chamber. In the
Howler Monkey or 'Mycetes' (see Fig. 16), the line passes obliquely
upwards and backwards, and the cerebral overlap is almost nil; while in
the Lemurs, as in the lower mammals, the line is much more inclined in
the same direction, and the cerebellar chamber projects considerably
beyond the cerebral.

When the gravest errors respecting points so easily settled as this
question respecting the posterior lobes can be authoritatively
propounded, it is no wonder that matters of observation, of no very
complex character, but still requiring a certain amount of care, should
have fared worse. Any one who cannot see the posterior lobe in an
ape's brain is not likely to give a very valuable opinion respecting
the posterior cornu or the hippocampus minor. If a man cannot see a
church, it is preposterous to take his opinion about its altar-piece or
painted window--so that I do not feel bound to enter upon any
discussion of these points, but content myself with assuring the reader
that the posterior cornu and the hippocampus minor, have now been
seen--usually, at least as well developed as in man, and often
better--not only in the Chimpanzee, the Orang, and the Gibbon, but in
all the genera of the old world baboons and monkeys, and in most of the
new world forms, including the Marmosets.*

[Footnote] *See the note at the end of this essay for a
succinct history of the controversy to which allusion is
here made.

FIG. 21.--Drawings of the cerebral hemispheres of a Man and of a
Chimpanzee of the same length, in order to show the relative
proportions of the parts: the former taken from a specimen, which Mr.
Flower, Conservator of the Museum of the Royal College of Surgeons, was
good enough to dissect for me; the latter, from the photograph of a
similarly dissected Chimpanzee's brain, given in Mr. Marshall's paper
above referred to. 'a', posterior lobe; 'b', lateral ventricle; 'c',
posterior cornu; 'x', the hippocampus minor.

In fact, all the abundant and trustworthy evidence (consisting of the
results of careful investigations directed to the determination of
these very questions, by skilled anatomists) which we now possess,
leads to the conviction that, so far from the posterior lobe, the
posterior cornu, and the hippocampus minor, being structures peculiar to
and characteristic of man, as they have been over and over again
asserted to be, even after the publication of the clearest
demonstration of the reverse, it is precisely these structures which are
the most marked cerebral characters common to man with the apes. They
are among the most distinctly Simian peculiarities which the human
organism exhibits.

As to the convolutions, the brains of the apes exhibit every stage of
progress, from the almost smooth brain of the Marmoset, to the Orang
and the Chimpanzee, which fall but little below Man. And it is most
remarkable that, as soon as all the principal sulci appear, the pattern
according to which they are arranged is identical with that of the
corresponding sulci of man. The surface of the brain of a monkey
exhibits a sort of skeleton map of man's, and in the man-like apes the
details become more and more filled in, until it is only in minor
characters, such as the greater excavation of the anterior lobes, the
constant presence of fissures usually absent in man, and the different
disposition and proportions of some convolutions, that the Chimpanzee's
or the Orang's brain can be structurally distinguished from Man's.

So far as cerebral structure goes, therefore, it is clear that Man
differs less from the Chimpanzee or the Orang, than these do even from
the Monkeys, and that the difference between the brains of the
Chimpanzee and of Man is almost insignificant, when compared with that
between the Chimpanzee brain and that of a Lemur.

It must not be overlooked, however, that there is a very striking
difference in absolute mass and weight between the lowest human brain
and that of the highest ape--a difference which is all the more
remarkable when we recollect that a full grown Gorilla is probably
pretty nearly twice as heavy as a Bosjes man, or as many an European
woman. It may be doubted whether a healthy human adult brain ever
weighed less than thirty-one or two ounces, or that the heaviest
Gorilla brain has exceeded twenty ounces.

This is a very noteworthy circumstance, and doubtless will one day help
to furnish an explanation of the great gulf which intervenes between
the lowest man and the highest ape in intellectual power;* but it has
little systematic value, for the simple reason that, as may be
concluded from what has been already said respecting cranial capacity,
the difference in weight of brain between the highest and the lowest
men is far greater, both relatively and absolutely, than that between
the lowest man and the highest ape. The latter, as has been seen, is
represented by, say twelve ounces of cerebral substance absolutely, or
by 32:20 relatively; but as the largest recorded human brain weighed
between 65 and 66 ounces, the former difference is represented by more
than 33 ounces absolutely, or by 65:32 relatively. Regarded
systematically, the cerebral differences of man and apes are not of more
than generic value; his Family distinction resting chiefly on his
dentition, his pelvis, and his lower limbs.

[Footnote] * I say 'help' to furnish: for I by no means
believe that it was any original difference of cerebral
quality, or quantity which caused that divergence between
the human and the pithecoid stirpes, which has ended in the
present enormous gulf between them. It is no doubt
perfectly true, in a certain sense, that all difference of
function is a result of difference of structure; or, in
other words, of difference in the combination of the
primary molecular forces of living substance; and, starting
from this undeniable axiom, objectors occasionally, and
with much seeming plausibility, argue that the vast
intellectual chasm between the Ape and Man implies a
corresponding structural chasm in the organs of the
intellectual functions; so that, it is said, the
non-discovery of such vast differences proves, not that
they are absent, but that Science is incompetent to detect
them. A very little consideration, however, will, I think,
show the fallacy of this reasoning. Its validity hangs
upon the assumption, that intellectual power depends
altogether on the brain--whereas the brain is only one
condition out of many on which intellectual manifestations
depend; the others being, chiefly, the organs of the senses
and the motor apparatuses, especially those which are
concerned in prehension and in the production of articulate

A man born dumb, notwithstanding his great cerebral mass and his
inheritance of strong intellectual instincts, would be capable of few
higher intellectual manifestations than an Orang or a Chimpanzee, if he
were confined to the society of dumb associates. And yet there might
not be the slightest discernible difference between his brain and that
of a highly intelligent and cultivated person. The dumbness might be
the result of a defective structure of the mouth, or of the tongue, or
a mere defective innervation of these parts; or it might result from
congenital deafness, caused by some minute defect of the internal ear,
which only a careful anatomist could discover.

The argument, that because there is an immense difference between a
Man's intelligence and an Ape's, therefore, there must be an equally
immense difference between their brains, appears to me to be about as
well based as the reasoning by which one should endeavour to prove
that, because there is a "great gulf" between a watch that keeps
accurate time and another that will not go at all, there is therefore a
great structural hiatus between the two watches. A hair in the
balance-wheel, a little rust on a pinion, a bend in a tooth of the
escapement, a something so slight that only the practised eye of the
watchmaker can discover it, may be the source of all the difference.

And believing, as I do, with Cuvier, that the possession of articulate
speech is the grand distinctive character of man (whether it be
absolutely peculiar to him or not), I find it very easy to comprehend,
that some equally inconspicuous structural difference may have been the
primary cause of the immeasurable and practically infinite divergence of
the Human from the Simian Stirps.

Thus, whatever system of organs be studied, the comparison of their
modifications in the ape series leads to one and the same result--that
the structural differences which separate Man from the Gorilla and the
Chimpanzee are not so great as those which separate the Gorilla from
the lower apes.

But in enunciating this important truth I must guard myself against a
form of misunderstanding, which is very prevalent. I find, in fact,
that those who endeavour to teach what nature so clearly shows us in
this matter, are liable to have their opinions misrepresented and their
phraseology garbled, until they seem to say that the structural
differences between man and even the highest apes are small and
insignificant. Let me take this opportunity then of distinctly
asserting, on the contrary, that they are great and significant; that
every bone of a Gorilla bears marks by which it might be distinguished
from the corresponding bone of a Man; and that, in the present
creation, at any rate, no intermediate link bridges over the gap
between 'Homo' and 'Troglodytes'.

It would be no less wrong than absurd to deny the existence of this
chasm; but it is at least equally wrong and absurd to exaggerate its
magnitude, and, resting on the admitted fact of its existence, to
refuse to inquire whether it is wide or narrow. Remember, if you will,
that there is no existing link between Man and the Gorilla, but do not
forget that there is a no less sharp line of demarcation, a no less
complete absence of any transitional form, between the Gorilla and the
Orang, or the Orang and the Gibbon. I say, not less sharp, though it is
somewhat narrower. The structural differences between Man and the
Man-like apes certainly justify our regarding him as constituting a
family apart from them; though, inasmuch as he differs less from them
than they do from other families of the same order, there can be no
justification for placing him in a distinct order.

And thus the sagacious foresight of the great lawgiver of systematic
zoology, Linnaeus, becomes justified, and a century of anatomical
research brings us back to his conclusion, that man is a member of the
same order (for which the Linnaean term PRIMATES ought to be retained)
as the Apes and Lemurs. This order is now divisible into seven
families, of about equal systematic value: the first, the ANTHROPINI,
contains Man alone; the second, the CATARHINI, embraces the old-world
apes; the third, the PLATYRHINI, all new-world apes, except the
Marmosets; the fourth, the ARCTOPITHECINI, contains the Marmosets; the
fifth, the LEMURINI, the Lemurs--from which 'Cheiromys' should probably
be excluded to form a sixth distinct family, the CHEIROMYINI; while the
seventh, the GALEOPITHECINI, contains only the flying Lemur
'Galeopithecus',-- a strange form which almost touches on the Bats, as
the 'Cheiromys' puts on a rodent clothing, and the Lemurs simulate

Perhaps no order of mammals presents us with so extraordinary a series
of gradations as this--leading us insensibly from the crown and summit
of the animal creation down to creatures, from which there is but a
step, as it seems, to the lowest, smallest, and least intelligent of
the placental Mammalia. It is as if nature herself had foreseen the
arrogance of man, and with Roman severity had provided that his
intellect, by its very triumphs, should call into prominence the
slaves, admonishing the conqueror that he is but dust.

These are the chief facts, this the immediate conclusion from them to
which I adverted in the commencement of this Essay. The facts, I
believe, cannot be disputed; and if so, the conclusion appears to me to
be inevitable.

But if Man be separated by no greater structural barrier from the brutes
than they are from one another--then it seems to follow that if any
process of physical causation can be discovered by which the genera and
families of ordinary animals have been produced, that process of
causation is amply sufficient to account for the origin of Man. In
other words, if it could be shown that the Marmosets, for example, have
arisen by gradual modification of the ordinary Platyrhini, or that both
Marmosets and Platyrhini are modified ramifications of a primitive
stock--then, there would be no rational ground for doubting that man
might have originated, in the one case, by the gradual modification of
a man-like ape; or, in the other case, as a ramification of the same
primitive stock as those apes.

At the present moment, but one such process of physical causation has
any evidence in its favour; or, in other words, there is but one
hypothesis regarding the origin of species of animals in general which
has any scientific existence--that propounded by Mr. Darwin. For
Lamarck, sagacious as many of his views were, mingled them with so much
that was crude and even absurd, as to neutralize the benefit which his
originality might have effected, had he been a more sober and cautious
thinker; and though I have heard of the announcement of a formula
touching "the ordained continuous becoming of organic forms," it is
obvious that it is the first duty of a hypothesis to be intelligible,
and that a qua-qua-versal proposition of this kind, which may be read
backwards, or forwards, or sideways, with exactly the same amount of
signification, does not really exist, though it may seem to do so.

At the present moment, therefore, the question of the relation of man to
the lower animals resolves itself, in the end, into the larger question
of the tenability, or untenability of Mr. Darwin's views. But here we
enter upon difficult ground, and it behoves us to define our exact
position with the greatest care.

It cannot be doubted, I think, that Mr. Darwin has satisfactorily proved
that what he terms selection, or selective modification, must occur,
and does occur, in nature; and he has also proved to superfluity that
such selection is competent to produce forms as distinct, structurally,
as some genera even are. If the animated world presented us with none
but structural differences, I should have no hesitation in saying that
Mr. Darwin had demonstrated the existence of a true physical cause,
amply competent to account for the origin of living species, and of man
among the rest.

But, in addition to their structural distinctions, the species of
animals and plants, or at least a great number of them, exhibit
physiological characters--what are known as distinct species,
structurally, being for the most part either altogether incompetent to
breed one with another; or if they breed, the resulting mule, or
hybrid, is unable to perpetuate its race with another hybrid of the
same kind.

A true physical cause is, however, admitted to be such only on one
condition--that it shall account for all the phenomena which come
within the range of its operation. If it is inconsistent with any one
phenomenon, it must be rejected; if it fails to explain any one
phenomenon, it is so far weak, so far to be suspected; though it may
have a perfect right to claim provisional acceptance.

Now, Mr. Darwin's hypothesis is not, so far as I am aware, inconsistent
with any known biological fact; on the contrary, if admitted, the facts
of Development, of Comparative Anatomy, of Geographical Distribution,
and of Palaeontology, become connected together, and exhibit a meaning
such as they never possessed before; and I, for one, am fully
convinced, that if not precisely true, that hypothesis is as near an
approximation to the truth as, for example, the Copernican hypothesis
was to the true theory of the planetary motions.

But, for all this, our acceptance of the Darwinian hypothesis must be
provisional so long as one link in the chain of evidence is wanting;
and so long as all the animals and plants certainly produced by
selective breeding from a common stock are fertile, and their progeny
are fertile with one another, that link will be wanting. For, so long,
selective breeding will not be proved to be competent to do all that is
required of it to produce natural species.

I have put this conclusion as strongly as possible before the reader,
because the last position in which I wish to find myself is that of an
advocate for Mr. Darwin's, or any other views--if by an advocate is
meant one whose business it is to smooth over real difficulties, and to
persuade where he cannot convince.

In justice to Mr. Darwin, however, it must be admitted that the
conditions of fertility and sterility are very ill understood, and that
every day's advance in knowledge leads us to regard the hiatus in his
evidence as of less and less importance, when set against the multitude
of facts which harmonize with, or receive an explanation from, his

I adopt Mr. Darwin's hypothesis, therefore, subject to the production of
proof that physiological species may be produced by selective breeding;
just as a physical philosopher may accept the undulatory theory of
light, subject to the proof of the existence of the hypothetical ether;
or as the chemist adopts the atomic theory, subject to the proof of the
existence of atoms; and for exactly the same reasons, namely, that it
has an immense amount of prima facie probability: that it is the only
means at present within reach of reducing the chaos of observed facts
to order; and lastly, that it is the most powerful instrument of
investigation which has been presented to naturalists since the
invention of the natural system of classification, and the commencement
of the systematic study of embryology.

But even leaving Mr. Darwin's views aside, the whole analogy of natural
operations furnishes so complete and crushing an argument against the
intervention of any but what are termed secondary causes, in the
production of all the phenomena of the universe; that, in view of the
intimate relations between Man and the rest of the living world, and
between the forces exerted by the latter and all other forces, I can
see no excuse for doubting that all are co-ordinated terms of Nature's
great progression, from the formless to the formed--from the inorganic
to the organic--from blind force to conscious intellect and will.

Science has fulfilled her function when she has ascertained and
enunciated truth; and were these pages addressed to men of science
only, I should now close this essay, knowing that my colleagues have
learned to respect nothing but evidence, and to believe that their
highest duty lies in submitting to it, however it may jar against their

But desiring, as I do, to reach the wider circle of the intelligent
public, it would be unworthy cowardice were I to ignore the repugnance
with which the majority of my readers are likely to meet the
conclusions to which the most careful and conscientious study I have
been able to give to this matter, has led me.

On all sides I shall hear the cry--"We are men and women, not a mere
better sort of apes, a little longer in the leg, more compact in the
foot, and bigger in brain than your brutal Chimpanzees and Gorillas.
The power of knowledge--the conscience of good and evil--the pitiful
tenderness of human affections, raise us out of all real fellowship with
the brutes, however closely they may seem to approximate us."

To this I can only reply that the exclamation would be most just and
would have my own entire sympathy, if it were only relevant. But, it
is not I who seek to base Man's dignity upon his great toe, or
insinuate that we are lost if an Ape has a hippocampus minor. On the
contrary, I have done my best to sweep away this vanity. I have
endeavoured to show that no absolute structural line of demarcation,
wider than that between the animals which immediately succeed us in the
scale, can be drawn between the animal world and ourselves; and I may
add the expression of my belief that the attempt to draw a psychical
distinction is equally futile, and that even the highest faculties of
feeling and of intellect begin to germinate in lower forms of life.* At
the same time, no one is more strongly convinced than I am of the
vastness of the gulf between civilized man and the brutes; or is more
certain that whether 'from' them or not, he is assuredly not 'of'
them. No one is less disposed to think lightly of the present dignity,
or desparingly of the future hopes, of the only consciously intelligent
denizen of this world.

[Footnote] * It is so rare a pleasure for me to find
Professor Owen's opinions in entire accordance with my own,
that I cannot forbear from quoting a paragraph which
appeared in his Essay "On the Characters, etc., of the
Class Mammalia," in the 'Journal of the Proceedings of the
Linnean Society of London' for 1857, but is unaccountably
omitted in the "Reade Lecture" delivered before the
University of Cambridge two years later, which is otherwise
nearly a reprint of the paper in question. Prof. Owen
writes: "Not being able to appreciate or conceive of the
distinction between the psychical phenomena of a Chimpanzee,
and of a Boschisman or of an Aztec, with arrested brain
growth, as being of a nature so essential as to preclude a
comparison between them, or as being other than a
difference of degree, I cannot shut my eyes to the
significance of that all-pervading similitude of
structure--every tooth, every bone, strictly
homologous--which makes the determination of the difference
between 'Homo' and 'Pithecus' the anatomist's difficulty."
Surely it is a little singular, that the 'anatomist,' who
finds it 'difficult' to 'determine the difference' between
'Homo' and 'Pithecus', should yet range them on anatomical
grounds, in distinct sub-classes!

We are indeed told by those who assume authority in these matters, that
the two sets of opinions are incompatible, and that the belief in the
unity of origin of man and brutes involves the brutalization and
degradation of the former. But is this really so? Could not a
sensible child confute by obvious arguments, the shallow rhetoricians
who would force this conclusion upon us? Is it, indeed, true, that the
Poet, or the Philosopher, or the Artist whose genius is the glory of
his age, is degraded from his high estate by the undoubted historical
probability, not to say certainty, that he is the direct descendant of
some naked and bestial savage, whose intelligence was just sufficient
to make him a little more cunning than the Fox, and by so much more
dangerous than the Tiger? Or is he bound to howl and grovel on all
fours because of the wholly unquestionable fact, that he was once an
egg, which no ordinary power of discrimination could distinguish from
that of a Dog? Or is the philanthropist or the saint to give up his
endeavours to lead a noble life, because the simplest study of man's
nature reveals, at its foundations, all the selfish passions and fierce
appetites of the merest quadruped? Is mother-love vile because a hen
shows it, or fidelity base because dogs possess it?

The common sense of the mass of mankind will answer these questions
without a moment's hesitation. Healthy humanity, finding itself hard
pressed to escape from real sin and degradation, will leave the
brooding over speculative pollution to the cynics and the 'righteous
overmuch' who, disagreeing in everything else, unite in blind
insensibility to the nobleness of the visible world, and in inability
to appreciate the grandeur of the place Man occupies therein.

Nay more, thoughtful men, once escaped from the blinding influences of
traditional prejudice, will find in the lowly stock whence Man has
sprung, the best evidence of the splendour of his capacities; and will
discern in his long progress through the Past, a reasonable ground of
faith in his attainment of a nobler Future.

They will remember that in comparing civilised man with the animal
world, one is as the Alpine traveller, who sees the mountains soaring
into the sky and can hardly discern where the deep shadowed crags and
roseate peaks end, and where the clouds of heaven begin. Surely the
awe-struck voyager may be excused if, at first, he refuses to believe
the geologist, who tells him that these glorious masses are, after all,
the hardened mud of primeval seas, or the cooled slag of subterranean
furnaces--of one substance with the dullest clay, but raised by inward
forces to that place of proud and seemingly inaccessible glory.

But the geologist is right; and due reflection on his teachings, instead
of diminishing our reverence and our wonder, adds all the force of
intellectual sublimity to the mere aesthetic intuition of the
uninstructed beholder.

And after passion and prejudice have died away, the same result will
attend the teachings of the naturalist respecting that great Alps and
Andes of the living world--Man. Our reverence for the nobility of
manhood will not be lessened by the knowledge that Man is, in substance
and in structure, one with the brutes; for, he alone possesses the
marvellous endowment of intelligible and rational speech, whereby, in
the secular period of his existence, he has slowly accumulated and
organized the experience which is almost wholly lost with the cessation
of every individual life in other animals; so that now he stands raised
upon it as on a mountain top, far above the level of his humble
fellows, and transfigured from his grosser nature by reflecting, here
and there, a ray from the infinite source of truth.

'A succinct History of the Controversy respecting the Cerebral Structure
of Man and the Apes'

UP to the year 1857 all anatomists of authority, who had occupied
themselves with the cerebral structure of the Apes--Cuvier, Tiedemann,
Sandifort, Vrolik, Isidore G. St. Hilaire, Schroeder van der Kolk,
Gratiolet--were agreed that the brain of the Apes possesses a POSTERIOR

Tiedemann, in 1825, figured and acknowledged in the text of his 'Icones'
the existence of the POSTERIOR CORNU of the lateral ventricle in the
Apes, not only under the title of 'Scrobiculus parvus loco cornu
posterioris'--a fact which has been paraded--but as 'cornu posterius'
('Icones', p. 54), a circumstance which has been, as sedulously, kept in
the background.

Cuvier ('Lecons', T. iii. p. 103) says, "the anterior or lateral
ventricles possess a digital cavity [posterior cornu] only in Man and
the Apes...its presence depends on that of the posterior lobes."

Schroeder van der Kolk and Vrolik, and Gratiolet, had also figured and
described the posterior cornu in various Apes. As to the HIPPOCAMPUS
MINOR Tiedemann had erroneously asserted its absence in the Apes; but
Schroeder van der Kolk and Vrolik had pointed out the existence of what
they considered a rudimentary one in the Chimpanzee, and Gratiolet had
expressly affirmed its existence in these animals. Such was the state
of our information on these subjects in the year 1856.

In the year 1857, however, Professor Owen, either in ignorance of these
well-known facts or else unjustifiably suppressing them, submitted to
the Linnaean Society a paper "On the Characters, Principles of
Division, and Primary Groups of the Class Mammalia," which was printed
in the Society's Journal, and contains the following passage:--"In Man,
the brain presents an ascensive step in development, higher and more
strongly marked than that by which the preceding sub-class was
distinguished from the one below it. Not only do the cerebral
hemispheres overlap and the olfactory lobes and cerebellum, but they
extend in advance of the one and further back than the other. The
posterior development is so marked, that anatomists have assigned to
that part the character of a third lobe; 'it is peculiar to the genus
Homo, and equally peculiar is the posterior horn of the lateral
ventricle and the 'hippocampus minor,' which characterise the hind lobe
of each hemisphere'."--'Journal of the Proceedings of the Linnaean
Society, Vol. ii. p. 19.

As the essay in which this passage stands had no less ambitious an aim
than the remodelling of the classification of the Mammalia, its author
might be supposed to have written under a sense of peculiar
responsibility, and to have tested, with especial care, the statements
he ventured to promulgate. And even if this be expecting too much,
hastiness, or want of opportunity for due deliberation, cannot now be
pleaded in extenuation of any shortcomings; for the propositions cited
were repeated two years afterwards in the Reade Lecture, delivered
before so grave a body as the University of Cambridge, in 1859.

When the assertions, which I have italicised in the above extract, first
came under my notice, I was not a little astonished at so flat a
contradiction of the doctrines current among well-indormed anatomists;
but, not unnaturally imagining that the deliberate statements of a
responsible person must have some foundation in fact, I deemed it my
duty to investigate the subject anew before the time at which it would
be my business to lecture thereupon came round. The result of my
inquiries was to prove that Mr. Owen's three assertions, that "the
third lobe, the posterior horn of the lateral ventricle, and the
hippocampus minor," are "pecular to the genus 'Homo'," are contrary to
the plainest facts. I communicated this conclusion to the students of
my class; and then, having no desire to embark in a controversy which
could not redound to the honour of British science, whatever its issue,
I turned to more congenial occupations.

The time speedily arrived, however, when a persistence in this reticence
would have involved me in an unworthy paltering with truth.

At the meeting of the British Association at Oxford, in 1860, Professor
Owen repeated these assertions in my presence, and, of course, I
immediately gave them a direct and unqualified contradiction, pledging
myself to justify that unusual procedure elsewhere. I redeemed that
pledge by publishing, in the January number of the 'Natural History
Review' for 1861, an article wherein the truth of the three following
propositions was fully demonstrated (l. c. p. 71):--

"1. That the third lobe is neither peculiar to, nor characteristic of,
man, seeing that it exists in all the higher quadrumana."

"2. That the posterior cornu of the lateral ventricle is neither
peculiar to, nor characteristic of, man, inasmuch as it also exists in
the higher quadrumana."

"3. That the 'hippocampus minor' is neither pecular to, nor
characteristic of, man, as it is found in certain of the higher

Furthermore, this paper contains the following paragraph (p. 76): "And
lastly, Schroeder van der Kolk and Vrolik (op. cit. p. 271), though
they particularly note that 'the lateral ventricle is distinguished
from that of Man by the very defective proportions of the posterior
cornu, wherein only a stripe is visible as an indication of the
hippocampus minor;' yet the Figure 4, in their second Plate, shows that
this posterior cornu is a perfectly distinct and unmistakeable
structure, quite as large as it often is in Man. It is the more
remarkable that Professor Owen should have overlooked the explicit
statement and figure of these authors, as it is quite obvious, on
comparison of the figures, that his woodcut of the brain of a Chimpanzee
(l. c. p. 19) is a reduced copy of the second figure of Messrs.
Schroeder van der Kolk and Vrolik's first Plate.

"As M. Gratiolet (l. c. p. 18), however is careful to remark,
'unfortunately the brain which they have taken as a model was greatly
altered (profondement affaisse), whence the general form of the brain
is given in these plates in a manner which is altogether incorrect.'
Indeed, it is perfectly obvious, from a comparison of a section of the
skull of the Chimpanzee with these figures, that such is the case; and
it is greatly to be regretted that so inadequate a figure should have
been taken as a typical representation of the Chimpanzee's brain."

From this time forth, the untenability of his position might have been
as apparent to Professor Owen as it was to every one else; but, so far
from retracting the grave errors into which he had fallen, Professor
Owen has persisted in and reiterated them; first, in a lecture
delivered before the Royal Institution on the 19th of March, 1861,
which is admitted to have been accurately reproduced in the 'Athenaeum'
for the 23rd of the same month, in a letter addressed by Professor Owen
to that journal on the 30th of March. The 'Athenaeum report was
accompanied by a diagram purporting to represent a Gorilla's brain, but
in reality so extraordinary a misrepresentation, that Professor Owen
substantially, though not explicitly, withdraws it in the letter in
question. In amending this error, however, Professor Owen fell into
another of much graver import, as his communication concludes with the
following paragraph: "For the true proportion in which the cerebrum
covers the cerebellum in the highest Apes, reference should be made to
the figure of the undissected brain of the Chimpanzee in my 'Reade's
Lecture on the Classification, etc., of the Mammalia', p. 25, fig. 7, 8
vo. 1859."

It would not be credible, if it were not unfortunately true, that this
figure, to which the trusting public is referred, without a word of
qualification, "for the true proportion in which the cerebrum covers
the cerebellum in the highest Apes," is exactly that unacknowledged copy
of Schroeder van der Kolk and Vrolik's figure whose utter inaccuracy
had been pointed out years before by Gratiolet, and had been brought to
Professor Owen's knowledge by myself in the passage of my article in
the 'Natural History Review' above quoted.

I drew public attention to this circumstance again in my reply to
Professor Owen, published in the 'Athenaeum' for April 13th, 1861; but
the exploded figure was reproduced once more by Professor Owen, without
the slightest allusion to its inaccuracy, in the 'Annals of Natural
History' for June 1861!

This proved too much for the patience of the original authors of the
figure, Messrs. Schroeder van der Kolk and Vrolik, who, in a note
addressed to the Academy of Amsterdam, of which they were members,
declared themselves to be, though decided opponents of all forms of the
doctrine of progressive development, above all things, lovers of truth:
and that, therefore, at whatever risk of seeming to lend support to
views which they disliked, they felt it their duty to take the first
opportunity of publicly repudiating Professor Owen's misuse of their

In this note they frankly admitted the justice of the criticisms of M.
Gratiolet, quoted above, and they illustrated, by new and careful
figures, the posterior lobe, the posterior cornu, and the hippocampus
minor of the Orang. Furthermore, having demonstrated the parts, at one
of the sittings of the Academy, they add, "la presence des parties
contestees y a ete universellement reconnue par les anatomistes
presents a la seance. Le seul doute qui soit reste se rapporte au pes
Hippocampi minor.... A l'etat frais l'indice du petit pied d'Hippocampe
etait plus prononce que maintenant."

Professor Owen repeated his erroneous assertions at the meeting of the
British Association in 1861, and again, without any obvious necessity,
and without adducing a single new fact or new argument, or being able
in any way to meet the crushing evidence from original dissections of
numerous Apes' brains, which had in the meanwhile been brought forward
by Prof. Rolleston,* F.R.S., Mr. Marshall,** F.R.S., Mr. Flower,*** Mr.
Turner,**** and myself,***** revived the subject at the Cambridge
meeting of the same body in 1862. Not content with the tolerably
vigorous repudiation which these unprecedented proceedings met with in
Section D, Professor Owen sanctioned the publication of a version of his
own statements, accompanied by a strange misrepresentation of mine (as
may be seen by comparison of the 'Times' report of the discussion), in
the 'Medical Times' for October 11th, 1862. I subjoin the conclusion
of my reply in the same journal for October 25th.

[Footnotes] * On the Affinities of the Brain of the Orang.
'Nat. Hist. Review', April, 1861.

** On the Brain of a young Chimpanzee. 'Ibid.', July, 1861.

*** On the Posterior lobes of the Cerebrum of the
Quadrumana. 'Philosophical Transactions', 1862.

**** On the anatomical Relations of the Surfaces of the
Tentorium to the Cerebrum and Cerebellum in Man and the
lower Mammals. 'Proceedings of the Royal Society of
Edinburgh', March, 1862.

***** On the Brain of Ateles. 'Proceedings of Zoological
Society', 1861.

"If this were a question of opinion, or a question of interpretation of
parts or of terms,--were it even a question of observation in which the
testimony of my own senses alone was pitted against that of another
person, I should adopt a very different tone in discussing this matter.
I should, in all humility, admit the likelihood of having myself erred
in judgment, failed in knowledge, or been blinded by prejudice.

"But no one pretends now, that the controversy is one of the terms or of
opinions. Novel and devoid of authority as some of Professor Owen's
proposed definitions may have been, they might be accepted without
changing the great features of the case. Hence though special
investigations into these matters have been undertaken during the last
two years by Dr. Allen Thomson, by Dr. Rolleston, by Mr. Marshall, and
by Mr. Flower, all, as you are aware, anatomists of repute in this
country, and by Professors Schroeder Van der Kolk, and Vrolik (whom
Professor Owen incautiously tried to press into his own service) on the
Continent, all these able and conscientious observers have with one
accord testified to the accuracy of my statements, and to the utter
baselessness of the assertions of Professor Owen. Even the venerable
Rudolph Wagner, whom no man will accuse of progressionist proclivities,
has raised his voice on the same side; while not a single anatomist,
great or small, has supported Professor Owen.

"Now, I do not mean to suggest that scientific differences should be
settled by universal suffrage, but I do conceive that solid proofs must
be met by something more than empty and unsupported assertions. Yet
during the two years through which this preposterous controversy has
dragged its weary length, Professor Owen has not ventured to bring
forward a single preparation in support of his often-repeated

"The case stands thus, therefore:--Not only are the statements made by
me in consonance with the doctrines of the best older authorities, and
with those of all recent investigators, but I am quite ready to
demonstrate them on the first monkey that comes to hand; while
Professor Owen's assertions are not only in diametrical opposition to
both old and new authorities, but he has not produced, and, I will add,
cannot produce, a single preparation which justifies them"

I now leave this subject, for the present.--For the credit of my calling
I should be glad to be, hereafter, for ever silent upon it. But,
unfortunately, this is a matter upon which, after all that has
occurred, no mistake or confusion of terms is possible--and in affirming
that the posterior lobe, the posterior cornu, and the hippocampus minor
exist in certain Apes, I am stating either that which is true, or that
which I must know to be false. The question has thus become one of
personal veracity. For myself, I will accept no other issue than this,
grave as it is, to the present controversy.

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