MAN AND THE APES
Objections to Zoölogical Discussion of Man's Place--Owen's
Prudence--Huxley's Determination to Speak out--Account of his
Treatment of _Man's Place in Nature_--Additions Made by More
Recent Work.
Even before the publication of _The Origin of Species_ there was a
considerable nervousness in the minds of the more orthodox as to
discussions on the position of the human species in zoölogical
classification. Men of the broadest minds, such as Lyell, who himself
had suffered considerably from outside interference with the
scientific right to publish scientific conclusions, was strongly
opposed to anything that seemed to tend towards breaking down the
barrier between man and the lower creatures. Sir William Lawrence, a
very distinguished and able man, had been criticised with the greatest
severity, and had been nearly ostracised, for a very mild little book
_On Man_; and Huxley tells us that the electors to the Chair of a
Scotch University had refused to invite a distinguished man, to whom
the post would have been acceptable, because he had advocated the view
that there were several species of man. The court political leaders,
and society generally, resented strongly anything that seemed at all
likely to disturb the somewhat narrow orthodoxy prevalent in those
times; and, as there were comparatively few posts open to scientific
men, and comparatively greater chances of posts being made for men of
talent and ability who adhered to the respectable traditions, those
who tampered with so serious a question as the place of man were
likely to burn their fingers severely. However, the difficulties of
discussing these problems were much greater immediately after 1859.
One of the most surprising things in the history of this century is
the sudden intensity of the opposition of the public, particularly the
respectable and religious public, to zoölogical writing upon man,
immediately after the publication of the _Origin_. Before that time
anatomists did not necessarily hesitate to point out the close
resemblance between the anatomy of man and that of the higher apes,
and the difficulties anatomists had in making anatomical distinction
of value between them. Thus Professor Owen, who, as a writer, was
rather unusually nervous about expressing facts to which any objection
might be raised by those outside the strictly scientific world, had
written the following paragraph in the course of an essay on the
characters of the class Mammalia, published, in 1857, in the _Journal
of the Proceedings of the Linnæan Society_:
"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."
It is true, he went on to explain his belief in the existence of
certain characters in the brain which seemed to him to justify the
separation of man in a different group from that in which the apes
were placed; but it is certain that he regretted having said anything
which seemed to support the Darwinian view; and, two years later, when
the opposition to Darwin was in its acutest stage, Owen withdrew his
words. His "Reade Lecture," delivered in the University of Cambridge,
was in all respects a reprint of the essay from which we have just
quoted, but the apparently dangerous words were omitted. More than
that, the points insisted on in the essay as being sufficient for the
purpose of separating man in zoölogical classification were elevated
into a reason against descent. Although Huxley, in several addresses
and publications, disproved the existence of the alleged differences,
and although Sir William Flower gave an actual demonstration shewing
the essential identity of the brain of man and of the apes in the
matter in question, Owen never admitted his error.
[Illustration: CHARLES DARWIN
From the painting by Hon. John Collier in the National Portrait
Gallery]
It is not surprising that, if an anatomist so distinguished and acute
as was Owen allowed his judgment to be completely overborne by the
storm of prejudice against Darwinism, those who were not anatomists
should have held up to ridicule all idea of comparison between man and
the apes. In _The Origin of Species_ itself, no elaborate attempt had
been made to set forth the anatomical arguments in favour of or
against a community of descent for man and the apes. But it was made
sufficiently plain, and the public laid hold of the point eagerly,
that the doctrine of descent was not meant to exclude man from the
field of its operation. Huxley, in the course of his ordinary work as
Professor of Biology, had, among many other subjects, naturally
turned his attention to the anatomy and classification of the
higher animals. When Owen's essay appeared, he found that he was
unable to agree with many of the conclusions contained in it, and had
set about a renewed investigation of the matter. Thus it happened
that, when the question became prominent, in 1860, Huxley was ready
with material contributions to it. He believed, moreover, that, as
Darwin was not specially acquainted with the anatomy and development
of vertebrates, there was an opportunity for doing a real service to
the cause of evolution. Accordingly, in 1860, he took for the subject
of a series of lectures to workingmen the "Relation of Man to the
Lower Animals," and, in 1862, expanded the lectures into a volume
called _Man's Place in Nature_. When it was ready, he was prepared to
say with a good conscience that his conclusions "had not been formed
hastily or enunciated crudely."
"I thought," he wrote in the preface to the 1894 edition, "I had
earned the right to publish them, and even fancied I might be
thanked, rather than reproved, for so doing. However, in my
anxiety to promulgate nothing erroneous, I asked a highly
competent anatomist and very good friend of mine to look through
my proofs, and, if he could, point out any errors of fact. I was
well pleased when he returned them without any criticism on that
score; but my satisfaction was speedily dashed by the very
earnest warning, as to the consequences of publication, which my
friend's interest in my welfare led him to give; but, as I have
confessed elsewhere, when I was a young man there was just a
little--a mere _soupçon_--in my composition of that tenacity of
purpose which has another name, and I felt sure that all the evil
things prophesied would not be so painful to me as the giving up
of that which I had resolved to do, upon grounds which I
conceived to be right. So the book came out, and I must do my
friend the justice to say that his forecast was completely
justified. The Boreas of criticism blew his hardest blasts of
misrepresentation and ridicule for some years; and I was even as
one of the wicked. Indeed, it surprises me, at times, to think
how anyone who had sunk so low could have emerged into, at any
rate, relative respectability."
Further, in the same preface, Huxley strongly advises others to
imitate his action in this matter. There are now, and no doubt there
always will be, truths "plainly obvious and generally denied." Whoever
attacks the current ideas is certain, unless human nature changes
greatly, to encounter a bitter opposition, and there will always be
those among his friends who recommend him to temper truth by prudence.
Huxley's advice is different:
"If there is a young man of the present generation who has taken
as much trouble as I did to assure himself that they are truths,
let him come out with them, without troubling his head about the
barking of the dogs of St. Ernulphus. _Veritas prævalebit_--some
day; and, even if she does not prevail in his time, he himself
will be all the better and wiser for having tried to help her.
And let him recollect that such great reward is full payment for
all his labour and pains."
Although they were written so long ago, the lectures on "Man's Place
in Nature" are still the best existing treatise on the subject, and we
shall give an outline of them, mentioning the chief points in which
further work has been done. Information concerning the man-like apes
was scattered in very different places, in the grave records of
scientific societies, in the letters of travellers and missionaries,
in the reports of the zoölogical societies which had been in
possession of living specimens. The facts had to be sifted out from a
great mass of verbiage and unfounded statement. With a characteristic
desire for historical accuracy, more usual in a man of letters than in
an anatomist, Huxley began with a study of classical and mediæval
legends of the existence of pigmies and man-like creatures; but, while
recognising that legends of satyrs and fauns were presages of the
discovery of man-like apes, he was unable to find any actual record
earlier than that contained in Pigafetta's _Description of the Kingdom
of Congo_, drawn up from the notes of a Portuguese sailor and
published in 1598. The descriptions and figures in this work
apparently referred to chimpanzees. From this date onwards he traces
the literature of the animals in question, and then proceeds to give
an account of them.
There are four distinct kinds of man-like apes: in Eastern Asia the
Orangs and the Gibbons (although some later writers differ from Huxley
in removing the Gibbons from the group of anthropoids); in Western
Africa, the Chimpanzees and the Gorillas. All these have certain
characters in common. They are inhabitants of the old world; they all
have the same number of teeth as man, possessing four incisors, two
canines, four premolars, and six true molars in each jaw, in the adult
condition, while the milk dentition, as in man, consists of twenty
teeth,--four incisors, two canines, and four molars in each jaw. Since
Huxley wrote, a large bulk of additional work upon teeth has been
published, and we now know that man and the anthropoid apes display
the same kind of degenerative specialisation in their jaws. Simpler
and older forms of mammals had a much larger number of teeth, and
these differed among themselves more than the teeth of the higher
forms. In the Anthropoids and Man, the jaws are proportionately
shorter and less heavy than in simpler forms, and, in correspondence
with this, the number of the teeth has become reduced, while the teeth
themselves tend to form a more even row. The canine or eye-teeth are
relatively smaller in the gorilla than in primitive mammals; they are
still smaller in the lower races of man; while in ordinary civilised
man they do not project above the others. The shortening of the jaw is
still proceeding, and, although in lower races of man the last molar
or wisdom tooth is almost as large as the molars in front of it, in
the higher races the wisdom tooth is much smaller and frequently does
not develop at all, or begins to decay very soon after its appearance.
If the process of extinction of lower races were to proceed much
further, so that civilised white races became the only human
inhabitants of the earth, then the gap between the Anthropoids and Man
would be wider than it now is; man would be characterised by the
presence of one tooth less than the anthropoids, just as the
anthropoids and some lower monkeys are characterised by having one
tooth less than monkeys still lower.
In all, the nostrils have a narrow partition and look downwards as in
man. The arms are always longer than the legs, the difference being
greatest in the orang and least in the chimpanzee. We know now that in
the lower races of man, the arms are proportionately longer than in
higher races, and it has recently been shewn that, although there is a
general proportion between the length of the long bones and the height
of the whole body in man, so that the height may be calculated with an
average error from these bones, yet the probable error is greater when
the calculation is made from the arms than when it is made from the
legs. In fact, the length of arm as compared to the length of leg and
to whole height is a more variable feature in man than the length of
leg.
In all the anthropoids, the forelimbs end in hands with longer or
shorter thumbs, and the great toe, always smaller than in man, is far
more movable and can be opposed like a thumb to the other toes. Since
Huxley wrote, a considerable amount of evidence has been collected
shewing that partial opposability of the toe in man is not uncommon,
and that there is evidence as to a tendency to increase of length of
the great toe within historical times. None of the great apes have
tails, and none of them have the cheek pouches common among lower
monkeys.
Huxley then gives an account of the natural history of these animals,
an account which still remains the best in literature. He sums up the
habits of the Asiatic forms as follows:
1. They may readily move along the ground in the erect, or semi-erect
position, and without direct support from the arms.
2. They may possess an extremely loud voice, so loud as to be readily
heard one or two miles.
3. They may be capable of great viciousness and violence when
irritated; and this is especially true of adult males.
4. They may build a nest to sleep in.
He finds the same general characters in the case of the gorilla and
chimpanzee, but in their case there was not quite so reliable evidence
upon which to go.
Although, since Huxley wrote, there has been much greater opportunity
of studying anthropoid apes, both in confinement and in their native
haunts, there is not much to add to his account. Some little time ago,
the world was interested by the assertion of a clever American that he
had discovered a kind of language used by the higher apes, and that he
was able to communicate with them. Mr. Garnier, the person in
question, declared his intention of going out to tropical Africa and
establishing himself in a strong cage in the forests inhabited by
gorillas and chimpanzees, in the hope that, impelled by curiosity,
they would look upon him as we look on monkeys in a zoölogical garden,
and that he would thus be able to make his knowledge and records of
monkey language more perfect. As a matter of fact he went to Africa,
and on his return published a volume which aroused the indignation of
naturalists. There was internal evidence that he had gone no further
than the garden of a coast station, and his pretended account of the
habits of monkeys as they lived in their native haunts contained
nothing that was not already known. There is no doubt but that the
anthropoid apes, like many other animals, use modulations of their
voice to express emotional states; that, in fact, they have love-cries
and cries of warning, of alarm, and of pleasure; but there is not the
smallest evidence to suppose that in the case of the anthropoids these
cries approach more nearly to speech than the cries of any other of
the higher mammals.
Since Huxley's volume was published, a large amount of information has
been published by Darwin, Romanes, and others upon the mental
capacities of anthropoids kept in confinement, and the result of this
has been to prove that the anthropoids, in especial the chimpanzees,
possess mental powers more akin to those of man than are to be found
in the most intelligent of the quadrupeds. We may cite some instances
of these higher powers. Vosmaern had a tame female orang-outang that
was able to untie the most intricate knot with fingers or teeth, and
took such pleasure in doing it that she regularly untied the shoes of
those who came near her. The female chimpanzee called Sally, that
lived for many years in the Zoölogical Society's Gardens in London,
was taught by its keeper and by Romanes an interesting variety of
"tricks" involving at least the rudiments of what may be called human
intelligence. Among other feats, it would pick up from the floor and
present to the keeper or to a visitor, a stated number of straws up to
five. Many monkeys seem nearly purely destructive in their dealings
with objects within their reach; but Leutemann tells of an
orang-outang which "tried to put to its proper use whatever was given
to him. To my great surprise he attempted to put on a pair of gloves.
He supported himself on a light walking cane and, when it bent under
him, made ridiculous motions to right it again." Brehm tells of a
chimpanzee:
"After eating, he at once begins to clean up. He holds a stick of
wood in front of him, or puts his hands in his master's slippers,
and slides about the room, then takes a cloth and scrubs the
floor. Scouring, sweeping, and dusting are his favourite
occupations; and, when he once gets hold of the cloth, he never
wants to give it up."
Falkenstein has given a detailed description of a gorilla which was
remarkable for his delicacy in eating.
"He would take a cup or glass with the greatest care, using both
hands to carry it to his mouth, and setting it down so carefully
that I do not remember having lost a single piece of crockery
through him, though we had never tried to teach him the use of
such vessels, wishing to bring him to Europe as nearly in his
natural condition as possible."
These and a multitude of similar observations which have been made
since Huxley wrote are typical of the increase of our knowledge on the
habits and capacities of the anthropoid apes. They all serve to show
that in them the instinct for experimental investigation of
everything with which they are surrounded, and their imitative
faculties are peculiarly great. The importance of this, from the point
of view of Huxley's argument, is great. The difference between the
instincts of the lower animals and the intelligence of man is that
instincts are to a large extent fixed and mechanical. The proper
performance of an instinct demands the presence of exactly the right
external conditions for its accomplishment. In the absence of these
conditions, the call to perform the instinctive action is equally
great, and results in useless performances. In many of the higher
animals these elaborate instincts are more general in their character,
and are supplemented by a considerable but varying aptitude for
modification of instinctive action to suit varieties of surrounding
circumstances. As this intelligence becomes more and more developed,
the blind, mechanical instinct becomes weaker. A large number of
instances might be given of such instincts modified by dawning
intelligence. The chief factors in producing the change are, as has
been shewn by Professor Groos, the possession of a general instinct to
imitate and to experiment, and the existence of a period of youth in
which the young creature may practise these instincts, and so prepare
itself for the more serious purposes of adult life. The anthropoid
apes seem to possess these experimental instincts to an extent much
greater than that observed in any other class of animals, and, as they
have a long period of youth, they have the opportunity of putting them
into practice to the fullest possible extent.
From the natural history of the anthropoid apes, Huxley passed to
consideration of their relation to man, prefacing his observations
with a passage defending the utility of the enquiry, a passage
necessary enough in these days of prejudice, but now chiefly with
historical interest:
"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 enquiry 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.
"The importance of such an enquiry 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 underworld 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 sciences."
Huxley then proceeded to elaborate the argument from development for
the essential identity of man and the apes. This argument has now
become more or less familiar to us all, as it has gained additional
support from recent extension of embryological knowledge, and as it
has been used in every work on evolution since Huxley first laid
stress on it. The adult forms of animals are much more complex than
their embryonic stages, and the series of changes passed through in
attaining the adult condition make up the embryological history of the
animal. Huxley took the embryology of the dog as an example of the
process in the higher animals generally, and as it had been worked out
in detail by a set of investigators. The dog, like all vertebrate
animals, begins its existence as an egg; and this body is just as much
an egg as that of a fowl, although, in the case of the dog, there is
not the accumulation of nutritive material which bloats the egg of the
hen into its enormous size. Since Huxley wrote, it has been shewn
clearly that among the mammalian animals there has been a gradual
reduction in the size of the egg. The ancestors of the mammals laid
large eggs, like those of birds or reptiles; and there still exist two
strange mammalian creatures, the Ornithorhynchus and Echidna of
Australia, which lay large, reptilian-like eggs. The ancestors of most
living mammalia acquired the habit of retaining the eggs within the
body until they were hatched; and, as a result of this, certain
structures which grow out from the embryo while it is still within the
egg and become applied to the inner wall of the porous shell for the
purpose of obtaining air, got their supply of oxygen, not from the
outer air, but from the blood-vessels of the maternal tissues. When
this connection (called the placenta) between embryo and mother
through the egg-shell became more perfect, not only oxygen but
food-material was obtained from the blood-vessels of the mother; and,
in consequence, it became unnecessary for the eggs to be provided with
a large supply of food-yolk. Among existing marsupial animals, which,
on the whole, represent a lower type of mammalian structure than
ordinary mammals, there is more food-yolk than in ordinary mammals,
and less food-yolk than in the two egg-laying mammals. In the ordinary
mammals, such as the rabbit, dog, monkey, and man, there is
practically no yolk whatever deposited in the egg; the egg is of
minute size, and the embryo obtains most of its food from the maternal
blood.
The small egg of the mammal divides into a number of cells, which form
a hollow sphere; on the upper surface of this the development of
organs begins with the formation of a depression which indicates the
future middle line of the animal, and is, in fact, the beginning of
the nervous system. Under this is formed a straight rod of gelatinous
material, the foundation of the vertebral column, and the body of the
embryo is gradually pinched off from the surface of the hollow sphere.
After tracing the details of this process, Huxley proceeded as
follows:
"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 yolk 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 embryos 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."
This general rule, that the longer the paths of embryonic development
of two animals keep identical the more nearly the two animals are
related, when Huxley wrote, was founded on a much smaller number of
facts than now are known. Since 1860 an enormous bulk of embryological
investigation has been published, and the total result has been to
confirm Huxley's position in the fullest possible way. A certain
number of exceptions have been found, but these exceptions are so
obviously special adaptations to special circumstances that their
existence only makes the general truth of the proposition more clear.
The most common kind of exception occurs when two closely related
animals live under very different conditions. For instance, many
marine animals have close allies that in comparatively recent times
have taken to live in fresh water. The conditions of life in fresh
water are very different, especially for delicate creatures
susceptible to rapid changes of temperature, or unable to withstand
strong currents. Thus most of the allies of the fresh-water crayfish,
which live in the sea, lay eggs from which there are soon hatched
minute, almost transparent larvæ, exceedingly unlike the adult. In the
comparatively equable temperature of sea-water, and in the usual
absence of strong currents, these small larvæ, as Huxley shewed later
in his volume on the _Crayfish_, live a free life, obtaining their own
food, and by a series of slow transformations gradually acquire the
adult form. In fresh water, however, the delicate larvæ would be
unable to live, and the mode of development is different. The series
of slow transformations is condensed, and takes place almost entirely
inside the egg-shell; so that, when hatching occurs, the young
crayfish is exceedingly like the adult. Apart from such special cases,
it is true that the study of development affords a clear test of
closeness of structural affinity.
Huxley then proceeds to discuss 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 animals immediately below him in the
scale; without doubt, in these respects, he is far nearer the
apes than the apes are to the dog."
Then, on lines with which, by continuous repetition and expansion by
authors subsequent to him, we have now become familiar, Huxley
compared, stage by stage, the development of man with that of other
animals, and shewed, first, its essential similarity, and then that in
every case where it departed from the development of the dog it
resembled more closely the development of the ape. He went on to
review the anatomy of man:
"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 organisation. He resembles them as they resemble one
another--he differs from, them as they differ from one another.
And, though these differences 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
zoölogists."
Having explained the general system of zoölogical classification, he
tried to dispel preliminary prejudice by inducing his readers or
bearers to take an outside view of themselves.
"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 enquiry 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."
In pursuit of this method, and taking the gorilla as the type for
immediate comparison with man, he passed in review the various
anatomical structures, shewing that in every case man did not differ
more from the gorilla than that differed from other anthropoids. We
shall take a few examples of his method and results, reminding our
readers, however, that Huxley carried his comparisons into every
important part of the anatomical structure.
There is no part of the skeleton so characteristically human as the
bones which form the pelvis, or bony girdle of the hips. The expanded
haunch-bones form a basin-like structure which affords support to the
soft internal viscera during the habitually upright position, and
gives space for the attachment of the very large muscles which help
man to assume and support that attitude. In the gorilla this region
differs considerably from that in man. The haunch-bones are narrower
and much shallower, so that they do not form so convenient a
supporting basin; they have much less surface for the attachment of
muscles. The gibbon, however, differs more vastly from the gorilla
than that differs from man. The haunch-bones are flat and narrow, and
totally devoid of any basin-like formation; the passage through the
pelvis is long and narrow, and the ischia have outwardly curved
prominences, which, in life, are coated by callosities on which the
animal habitually rests, and which are coarse, corn-like patches of
skin wholly absent in the gorilla, in the chimpanzee, in the orang,
and in man.
In the characters of the hands, the feet, and the brain, certain real
or supposed structural distinctions between man and the apes had been
relied upon.
"Man has been defined as the only animal possessed of two hands
terminating his fore-limbs, and of two feet terminating 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 reasserted, 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 enquirers who have specially
investigated the matter; and that it has neither 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 foundation."
The last remarks referred, of course, to the statements of Owen, which
had made a great impression at the time and the result of which still
lingers in some of the worse-informed treatises attacking evolution.
Huxley gave a lucid account of the general structure and arrangement
of the brain in the vertebrate series, explaining the well-known fact
that from fish up to man the general ground-plan of the brain is
identical, but that there is a progressive increase in the complexity
and in the size of some parts compared with others. Next, he showed
that, so far from its being possible to erect any barrier in the
structure of the brain between man and the apes, there exists among
the mammals an almost complete series of gradations from brains a
little higher than that of the rabbit to brains a little lower than
that of man. He laid great stress on
"the remarkable circumstance that though, so far as our present
knowledge extends, there _is_ one 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 minor." ... "So far from the posterior
lobe, the posterior cornu, and the hippocampus minor being
structures peculiar to, and characteristic of man, as they have
over and over again been 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." ... "Man differs from the chimpanzee or the orang, so
far as cerebral structure goes, less than these do from the
monkeys, and 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."
Although Huxley found no structural differences between the brains of
man and of anthropoid apes, he was careful to lay great stress on the
important difference in size and weight. A full-grown gorilla is
nearly twice as heavy as a European woman, and yet the heaviest known
gorilla brain probably does not exceed twenty ounces in weight, while
healthy adult human brains probably never weigh less than thirty-one
or thirty-two ounces. This difference is not of systematic importance;
for cranial capacities shew that relatively and absolutely there is a
greater difference in brain-weight between the lowest and highest
human beings than there is between the highest ape and the lowest
human being.
In dealing with the suggestion that man differs from the apes in being
bimanous, while the apes are quadrumanous, Huxley first explained and
discussed what the exact differences between hands and feet are. He
shewed that in man the foot is absolutely distinguished from the hand
by three structural points, although the two organs are similar in
general ground-plan. These structural points are:
1. The arrangement of the tarsal bones.
2. The possession of a short flexor and short extensor muscle of the
digits.
3. The possession of a muscle named _peronæus longus_.
Then he described the foot of the gorilla, and shewed that although it
was superficially hand-like, it possessed all the structural
characters that distinguish a foot from a hand. Tracing the structure
of the foot downwards through the series of anthropoids and monkeys,
he established clearly that, while important differences existed in
nearly every single creature, the differences between the gorilla and
man were not greater than those between the gorilla and other
anthropoids, and less than between the gorilla and lower monkeys.
This wonderful series of lectures ranks very high among the important
works of Huxley. It is true that a considerable proportion of the work
was not absolutely original, but it had all been specially verified by
him. It was a task undertaken with the greatest courage, and with a
care equal to the courage; and it settled conclusively for all time
the impossibility of making between man and the anthropoids any
anatomical barriers greater than those which exist between the
different although closely related members of any of the other family
groups in the animal kingdom. The advance of knowledge has only added
to the details of Huxley's argument; it has not made any
reconstruction of it necessary. A writer on the same subject to-day
would to all certainty make use of the same general methods. The chief
differences, perhaps, that would be made are two: First, greater
stress would be laid on the distinction, first made by Huxley himself,
between intermediate and linear types. (See p. 87). To use the popular
phrase, a great deal of water has passed under the bridges since the
separation of man from the ape-like progenitors common to him and to
the existing anthropoids. It has already been pointed out that the
gradual extinction of lower races of man is widening the apparent gap
between existing man and existing apes; and evidence accumulates that
many still more primitive and more ape-like races of man than the
lowest existing savages have disappeared from the surface of the
earth. Moreover, we know that existing anthropoids are the degenerate
and scattered remnants of what was once a much more widely spread and
more important group. We have some reason for believing the contrary,
and no reason for believing that the surviving anthropoids represent
the most man-like apes that have lived.
The second great point in which a modern writer would amend Huxley's
statement of the case is more purely anatomical. One result of
Darwin's work has been that anatomists attend much more closely to the
slight variations of anatomical structure to be found among
individuals of the same species. A comparison between an individual
human body and the body of an individual gorilla is not now considered
sufficient. The comparison must be made between the results of
dissection of a very large number of men and of a very large number of
gorillas. The anatomy of a type is not the anatomy of an individual;
it is a kind of central point around which there oscillate the
variations presented by the individuals belonging to the type. So far
as this newer method has been applied, it has been found that the
variations of the gorilla type frequently, in the case of individual
organs, overlap the variations of the human type, and that the
structure of man differs from the structure of any anthropoid type
only in that the abstract central point of its variations is slightly
different from the abstract central point of the variations presented
by individual orangs, gorillas, and chimpanzees.