HE WHO wishes
to decide whether man is the
modified descendant
of some pre-existing form, would
probably first enquire whether
man varies, however slightly,
in bodily structure and in mental
faculties; and if so, whether
the variations are transmitted
to his offspring in accordance
with the laws which prevail with
the lower animals. Again, are
the variations the result, as
far as our ignorance permits
us to judge, of the same general
causes, and are they governed
by the same general laws, as
in the case of other organisms;
for instance, by correlation,
the inherited effects of use
and disuse, &c.? Is man subject
to similar malconformations,
the result of arrested development,
of reduplication of parts, &c.,
and does he display in any of
his anomalies reversion to some
former and ancient type of structure?
It might also naturally be enquired
whether man, like so many other
animals, has given rise to varieties
and sub-races, differing but
slightly from each other, or
to races differing so much that
they must be classed as doubtful
species? How are such races distributed
over the world; and how, when
crossed, do they react on each
other in the first and succeeding
generations? And so with many
other points.
The enquirer would next come
to the important point, whether
man tends to increase at so rapid
a rate, as to lead to occasional
severe struggles for existence;
and consequently to beneficial
variations, whether in body or
mind, being preserved, and injurious
ones eliminated. Do the races
or species of men, whichever
term may be applied, encroach
on and replace one another, so
that some finally become extinct?
We shall see that all these questions,
as indeed is obvious in respect
to most of them, must be answered
in the affirmative, in the same
manner as with the lower animals.
But the several considerations
just referred to may be conveniently
deferred for a time: and we will
first see how far the bodily
structure of man shows traces,
more or less plain, of his descent
from some lower form. In succeeding
chapters the mental powers of
man, in comparison with those
of the lower animals, will be
considered.
The Bodily Structure
of Man. It is notorious that
man is constructed
on the same general type or model
as other mammals. All the bones
in his skeleton can be compared
with corresponding bones in a
monkey, bat, or seal. So it is
with his muscles, nerves, blood-vessels
and internal viscera. The brain,
the most important of all the
organs, follows the same law,
as shewn by Huxley and other
anatomists. Bischoff,* who is
a hostile witness, admits that
every chief fissure and fold
in the brain of man has its analogy
in that of the orang; but he
adds that at no period of development
do their brains perfectly agree;
nor could perfect agreement be
expected, for otherwise their
mental powers would have been
the same. Vulpian*(2) remarks: "Les
differences reelles qui existent
entre l'encephale de l'homme
et celui des singes superieurs,
sont bien minimes. It ne faut
pas se faire d'illusions a cet
egard. L'homme est bien plus
pres des singes anthropomorphes
par les caracteres anatomiques
de son cerveau que ceux-ci ne
le sont non seulement des autres
mammiferes, mais meme de certains
quadrumanes, des guenons et des
macaques." But it would be superfluous
here to give further details
on the correspondence between
man and the higher mammals in
the structure of the brain and
all other parts of the body.
* Grosshirnwindungen des Menschen,
1868, s. 96. The conclusions
of this author, as well as those
of Gratiolet and Aeby, concerning
the brain, will be discussed
by Prof. Huxley in the appendix.
*(2) Lec. sur la Phys., 1866,
p. 890, as quoted by M. Dally,
L'Ordre des Primates et le Transformisme,
1868, p. 29.
It may, however, be worth while
to specify a few points, not
directly or obviously connected
with structure, by which this
correspondence or relationship
is well shewn.
Man is liable
to receive from the lower animals,
and to communicate
to them, certain diseases, as
hydrophobia, variola, the glanders,
syphilis, cholera, herpes, &c.;*
and this fact proves the close
similarity*(2) of their tissues
and blood, both in minute structure
and composition, far more plainly
than does their comparison under
the best microscope, or by the
aid of the best chemical analysis.
Monkeys are liable to many of
the same non-contagious diseases
as we are; thus Rengger,*(3)
who carefully observed for a
long time the Cebus azarae in
its native land, found it liable
to catarrh, with the usual symptoms,
and which, when often recurrent,
led to consumption. These monkeys
suffered also from apoplexy,
inflammation of the bowels, and
cataract in the eye.The younger
ones when shedding their milk-teeth
often died from fever. Medicines
produced the same effect on them
as on us. Many kinds of monkeys
have a strong taste for tea,
coffee, and spirituous liquors:
they will also, as I have myself
seen, smoke tobacco with pleasure.*(4)
Brehm asserts that the natives
of north-eastern Africa catch
the wild baboons by exposing
vessels with strong beer, by
which they are made drunk. He
has seen some of these animals,
which he kept in confinement,
in this state; and he gives a
laughable account of their behaviour
and strange grimaces. On the
following morning they were very
cross and dismal; they held their
aching heads with both hands,
and wore a most pitiable expression:
when beer or wine was offered
them, they turned away with disgust,
but relished the juice of lemons.*(5)
An American monkey, an Ateles,
after getting drunk on brandy,
would never touch it again, and
thus was wiser than many men.
These trifling facts prove how
similar the nerves of taste must
be in monkeys and man, and how
similarly their whole nervous
system is affected.
* Dr. W. Lauder Lindsay has
treated this subject at some
length in the Journal of Mental
Science, July, 1871: and in the
Edinburgh Veterinary Review,
July, 1858.
*(2) A reviewer has criticised
(British Quarterly Review, Oct.
1, 1871, p. 472) what I have
here said with much severity
and contempt: but as I do not
use the term identity, I cannot
see that I am greatly in error.
There appears to me a strong
analogy between the same infection
or contagion producing the same
result, or one closely similar,
in two distinct animals, and
the testing of two distinct fluids
by the same chemical reagent.
*(3) Naturgeschichte der Saugethiere
von Paraguay, 1830, s. 50.
*(4) The same tests are common
to some animals much lower in
the scale. Mr. A. Nicols informs
me that he kept in Queensland,
in Australia, three individuals
of the Phaseolarctus cinereus,
and that, without having been
taught in any way, they acquired
a strong taste for rum, and for
smoking tobacco.
*(5) Brehm, Illustriertes Thierleben,
B. i., 1864, 75, 86. On the Ateles,
s. 105. For other analogous statements,
see ss. 25, 107.
Man is infested with internal
parasites, sometimes causing
fatal effects; and is plagued
by external parasites, all of
which belong to the same genera
or families as those infesting
other mammals, and in the case
of scabies to the same species.*
Man is subject, like other mammals,
birds, and even insects,*(2)
to that mysterious law, which
causes certain normal processes,
such as gestation, as well as
the maturation and duration of
various diseases, to follow lunar
periods. His wounds are repaired
by the same process of healing;
and the stumps left after the
amputation of his limbs, especially
during an early embryonic period,
occasionally possess some power
of regeneration, as in the lowest
animals.*(3)
* Dr. W. Lauder Lindsay, Edinburgh
Veterinary Review, July, 1858,
p. 13.
*(2) With respect
to insects see Dr. Laycock, "On a General
Law of Vital Periodicity," British
Association, 1842. Dr. Macculloch,
Silliman's North American Journal
of Science, vol. xvii., p. 305,
has seen a dog suffering from
tertian ague. Hereafter I shall
return to this subject.
*(3) I have given the evidence
on this head in my Variation
of Animals and Plants under Domestication,
vol. ii., p. 15, and more could
be added.
The whole process
of that most important function,
the reproduction
of the species, is strikingly
the same in all mammals, from
the first act of courtship by
the male,* to the birth and nurturing
of the young. Monkeys are born
in almost as helpless a condition
as our own infants; and in certain
genera the young differ fully
as much in appearance from the
adults, as do our children from
their full-grown parents.*(2)
It has been urged by some writers,
as an important distinction,
that with man the young arrive
at maturity at a much later age
than with any other animal: but
if we look to the races of mankind
which inhabit tropical countries
the difference is not great,
for the orang is believed not
to be adult till the age of from
ten to fifteen years.*(3) Man
differs from woman in size, bodily
strength, hairiness, &c., as
well as in mind, in the same
manner as do the two sexes of
many mammals. So that the correspondence
in general structure, in the
minute structure of the tissues,
in chemical composition and in
constitution, between man and
the higher animals, especially
the anthropomorphous apes, is
extremely close.
* Mares e diversis generibus
Quadrumanorum sine dubio dignoscunt
feminas humanas a maribus. Primum,
credo, odoratu, postea aspectu.
Mr. Youatt, qui diu in Hortis
Zoologicis (Bestiariis) medicus
animalium erat, vir in rebus
observandis cautus et sagax,
hoc mihi certissime probavit,
et curatores ejusdem loci et
alii e ministirs confirmaverunt.
Sir Andrew Smith et Brehm notabant
idem in Cynocephalo. Illustrissimus
Cuvier etiam narrat multa de
hac re, qua ut opinor, nihil
turpius potest indicari inter
omnia hominibus et Quadrumanis
communia. Narrat enim Cynocephalum
quendam in furorem incidere aspectu
feminarum aliquarem, sed nequaquam
accendi tanto furore ab omnibus.
Semper eligebat juniores, et
dignoscebat in turba, et advocabat
voce gestuque.
*(2) This remark is made with
respect to Cynocephalus and the
anthropomorphous apes by Geoffroy
Saint-Hilaire and F. Cuvier,
Histoire Nat. des Mammiferes,
tom. i., 1824.
*(3) Huxley, Man's Place in
Nature, 1863, p. 34.
Embryonic Development.
Man is developed from an ovule,
about
the 125th of an inch in diameter,
which differs in no respect from
the ovules of other animals.
The embryo itself at a very early
period can hardly be distinguished
from that of other members of
the vertebrate kingdom. At this
period the arteries run in arch-like
branches, as if to carry the
blood to branchiae which are
not present in the higher Vertebrata,
though the slits on the sides
of the neck still remain (see
f, g, fig. 1), marking their
former position. At a somewhat
later period, when the extremities
are developed, "the feet of lizards
and mammals," as the illustrious
von Baer remarks, "the wings
and feet of birds, no less than
the hands and feet of man, all
arise from the same fundamental
form." It is, says Prof. Huxley,* "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 developments,
as the man does. Startling as
this last assertion may appear
to be, it is demonstrably true."
* Man's Place in Nature, 1863,
p. 67.
As some of my readers may never
have seen a drawing of an embryo,
I have given one of man and another
of a dog, at about the same early
stage of development, carefully
copied from two works of undoubted
accuracy.*
* The human embryo (see upper
fig.) is from Ecker, Icones Phys.,
1851-1859, tab. xxx., fig. 2.
The drawing of this embryo is
much magnified. The embryo of
the dog is from Bischoff, Entwicklungsgeschichte
des Hunde-Eies, 1845, tab. xi.,
fig. 42 B. This drawing is magnified,
the embryo being twenty-five
days old. The internal viscera
have been omitted, and the uterine
appendages in both drawings removed.
I was directed to these figures
by Prof. Huxley, from whose work,
Man's Place in Nature, the idea
of giving them was taken. Haeckel
has also given analogous drawings
in his Schopfungsgeschichte.
After the foregoing
statements made by such high
authorities,
it would be superfluous on my
part to give a number of borrowed
details, shewing that the embryo
of man closely resembles that
of other mammals. It may, however,
be added, that the human embryo
likewise resembles certain low
forms when adult in various points
of structure. For instance, the
heart at first exists as a simple
pulsating vessel; the excreta
are voided through a cloacal
passage; and the os coccyx projects
like a true extending considerably
beyond the rudimentary legs."*
In the embryos of all air-breathing
vertebrates, certain glands,
called the corpora Wolffiana,
correspond with, and act like
the kidneys of mature fishes.*(2)
Even at a later embryonic period,
some striking resemblances between
man and the lower animals may
be observed. Bischoff says "that
the convolutions of the brain
in a human foetus at the end
of the seventh month reach about
the same stage of development
as in a baboon when adult."*(3)
The great toe, as Professor Owen
remarks,*(4) "which forms the
fulcrum when standing or walking,
is perhaps the most characteristic
peculiarity in the human structure";
but in an embryo, about an inch
in length, Prof. Wyman*(5) found "that
the great toe was shorter than
the others; and, instead of being
parallel to them, projected at
an angle from the side of the
foot, thus corresponding with
the permanent condition of this
part in the Quadrumana." I will
conclude with a quotation from
Huxley,*(6) who, after asking
does man originate in a different
way from a dog, bird, frog or
fish, says, "The reply is not
doubtful for a moment; 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 to apes than the apes
are to the dog."
* Prof. Wyman in Proceedings
of the American Academy of Sciences,
vol. iv., 1860, p. 17.
*(2) Owen, Anatomy of Vertebrates,
vol. i., p. 533.
*(3) Die Grosshirnwindungen
des Menschen 1868, s. 95.
*(4) Anatomy of Vertebrates,
vol. ii., p. 553.
*(5) Proc. Soc. Nat. Hist.,
Boston, 1863, vol. ix., p. 185.
*(6) Man's Place in Nature,
p. 65.
Rudiments. This subject, though
not intrinsically more important
than the two last, will for several
reasons be treated here more
fully.* Not one of the higher
animals can be named which does
not bear some part in a rudimentary
condition; and man forms no exception
to the rule. Rudimentary organs
must be distinguished from those
that are nascent; though in some
cases the distinction is not
easy. The former are either absolutely
useless, such as the mammee of
male quadrupeds, or the incisor
teeth of ruminants which never
cut through the gums; or they
are of such slight service to
their present possessors, that
we can hardly suppose that they
were developed under the conditions
which now exist. Organs in this
latter state are not strictly
rudimentary, but they are tending
in this direction. Nascent organs,
on the other hand, though not
fully developed, are of high
service to their possessors,
and are capable of further development.
Rudimentary organs are eminently
variable; and this is partly
intelligible, as they are useless,
or nearly useless, and consequently
are no longer subjected to natural
selection. They often become
wholly suppressed. When this
occurs, they are nevertheless
liable to occasional reappearance
through reversion- a circumstance
well worthy of attention.
* I had written
a rough copy of this chapter
before reading
a valuable paper, "Caratteri
rudimentali in ordine all' origine
dell' uomo" (Annuario della Soc.
d. Naturalisti, Modena, 1867,
p. 81), by G. Canestrini, to
which paper I am considerably
indebted. Haeckel has given admirable
discussions on this whole subject,
under the title of "Dysteleology," in
his Generelle Morphologie and
Shopfungsgeschichte.
The chief agents
in causing organs to become
rudimentary
seem to have been disuse at that
period of life when the organ
is chiefly used (and this is
generally during maturity), and
also inheritance at a corresponding
period of life. The term "disuse" does
not relate merely to the lessened
action of muscles, but includes
a diminished flow of blood to
a part or organ, from being subjected
to fewer alternations of pressure,
or from becoming in any way less
habitually active. Rudiments,
however, may occur in one sex
of those parts which are normally
present in the other sex; and
such rudiments, as we shall hereafter
see, have often originated in
a way distinct from those here
referred to. In some cases, organs
have been reduced by means of
natural selection, from having
become injurious to the species
under changed habits of life.
The process of reduction is probably
often aided through the two principles
of compensation and economy of
growth; but the later stages
of reduction, after disuse has
done all that can fairly be attributed
to it, and when the saving to
be effected by the economy of
growth would be very small,*
are difficult to understand.
The final and complete suppression
of a part, already useless and
much reduced in size, in which
case neither compensation or
economy can come into play, is
perhaps intelligible by the aid
of the hypothesis of pangenesis.
But as the whole subject of rudimentary
organs has been discussed and
illustrated in my former works,*(2)
I need here say no more on this
head.
* Some good criticisms on this
subject have been given by Messrs.
Murie and Mivart, in Transactions,
Zoological Society, 1869, vol.
vii., p. 92.
*(2) Variation of Animals and
Plants under Domestication, vol.
ii pp. 317 and 397. See also
Origin of Species.(OOS)
Rudiments of
various muscles have been observed
in many parts
of the human body;* and not a
few muscles, which are regularly
present in some of the lower
animals can occasionally be detected
in man in a greatly reduced condition.
Every one must have noticed the
power which many animals, especially
horses, possess of moving or
twitching their skin; and this
is effected by the panniculus
carnosus. Remnants of this muscle
in an efficient state are found
in various parts of our bodies;
for instance, the muscle on the
forehead, by which the eyebrows
are raised. The platysma myoides,
which is well developed on the
neck, belongs to this system.
Prof. Turner, of Edinburgh, has
occasionally detected, as he
informs me, muscular fasciculi
in five different situations,
namely in the axillae, near the
scapulae, &c., all of which must
be referred to the system of
the panniculus. He has also shewn*(2)
that the musculus sternalis or
sternalis brutorum, which is
not an extension of the rectus
abdominalis, but is closely allied
to the panniculus, occurred in
the proportion of about three
per cent. in upward of 600 bodies:
he adds, that this muscle affords "an
excellent illustration of the
statement that occasional and
rudimentary structures are especially
liable to variation in arrangement."
* For instance,
M. Richard (Annales des Sciences
Nat., 3d series,
Zoolog., 1852, tom. xviii., p.
13) describes and figures rudiments
of what he calls the "muscle
pedieux de la main," which he
says is sometimes "infiniment
petit." Another muscle, called "le
tibial posterieur," is generally
quite absent in the hand, but
appears from time to time in
a more or less rudimentary condition.
*(2) Prof. W. Turner, Proceedings
of the Royal Society of Edinburgh,
1866-67, p. 65.
Some few persons have the power
of contracting the superficial
muscles on their scalps; and
these muscles are in a variable
and partially rudimentary condition.
M.A. de Candolle has communicated
to me a curious instance of the
long-continued persistence or
inheritance of this power, as
well as of its unusual development.
He knows a family, in which one
member, the present head of the
family, could, when a youth,
pitch several heavy books from
his head by the movement of the
scalp alone; and he won wagers
by performing this feat. His
father, uncle, grandfather, and
his three children possess the
same power to the same unusual
degree. This family became divided
eight generations ago into two
branches; so that the head of
the above-mentioned branch is
cousin in the seventh degree
to the head of the other branch.
This distant cousin resides in
another part of France; and on
being asked whether he possessed
the same faculty, immediately
exhibited his power. This case
offers a good illustration how
persistent may be the transmission
of an absolutely useless faculty,
probably derived from our remote
semi-human progenitors; since
many monkeys have, and frequently
use the power, of largely moving
their scalps up and down.*
* See my Expression of the Emotions
in Man and Animals, 1872, p.
144.
The extrinsic
muscles which serve to move
the external ear,
and the intrinsic muscles which
move the different parts, are
in a rudimentary condition in
man, and they all belong to the
system of the panniculus; they
are also variable in development,
or at least in function. I have
seen one man who could draw the
whole ear forwards; other men
can draw it upwards; another
who could draw it backwards;*
and from what one of these persons
told me, it is probable that
most of us, by often touching
our ears, and thus directing
our attention towards them, could
recover some power of movement
by repeated trials. The power
of erecting and directing the
shell of the ears to the various
points of the compass, is no
doubt of the highest service
to many animals, as they thus
perceive the direction of danger;
but I have never heard, on sufficient
evidence, of a man who possessed
this power, the one which might
be of use to him. The whole external
shell may be considered a rudiment,
together with the various folds
and prominences (helix and anti-helix,
tragus and anti-tragus, &c.)
which in the lower animals strengthen
and support the ear when erect,
without adding much to its weight.
Some authors, however, suppose
that the cartilage of the shell
serves to transmit vibrations
to the acoustic nerve; but Mr.
Toynbee,*(2) after collecting
all the known evidence on this
head, concludes that the external
shell is of no distinct use.
The ears of the chimpanzee and
orang are curiously like those
of man, and the proper muscles
are likewise but very slightly
developed.*(3) I am also assured
by the keepers in the Zoological
Gardens that these animals never
move or erect their ears; so
that they are in an equally rudimentary
condition with those of man,
as far as function is concerned.
Why these animals, as well as
the progenitors of man, should
have lost the power of erecting
their ears, we can not say. It
may be, though I am not satified
with this view, that owing to
their arboreal habits and great
strength they were but little
exposed to danger, and so during
a lengthened period moved their
ears but little, and thus gradually
lost the power of moving them.
This would be a parallel case
with that of those large and
heavy birds, which, from inhabiting
oceanic islands, have not been
exposed to the attacks of beasts
of prey, and have consequently
lost the power of using their
wings for flight. The inability
to move the ears in man and several
apes is, however, partly compensated
by the freedom with which they
can move the head in a horizontal
plane, so as to catch sounds
from all directions. It has been
asserted that the ear of man
alone possesses a lobule; but "a
rudiment of it is found in the
gorilla";*(4) and, as I hear
from Prof. Preyer, it is not
rarely absent in the negro.
* Canestrini quotes Hyrtl. (Annuario
della Soc. dei Naturalisti, Modena,
1897, p. 97) to the same effect.
*(2) The Diseases of the Ear,
by J. Toynbee, F. R. S., 1860,
p. 12. A distinguished physiologist,
Prof. Preyer, informs me that
he had lately been experimenting
on the function of the shell
of the ear, and has come to nearly
the same conclusion as that given
here.
*(3) Prof. A. Macalister, Annals
and Magazine of Natural History,
vol. vii., 1871, p. 342.
*(4) Mr. St. George Mivart,
Elementary Anatomy, 1873, p.
396.
The celebrated
sculptor, Mr. Woolner, informs
me of one little
peculiarity in the external ear,
which he has often observed both
in men and women, and of which
he perceived the full significance.
His attention was first called
to the subject whilst at work
on his figure of Puck, to which
he had given pointed ears. He
was thus led to examine the ears
of various monkeys, and subsequently
more carefully those of man.
The peculiarity consists in a
little blunt point, projecting
from the inwardly folded margin,
or helix. When present, it is
developed at birth, and according
to Prof. Ludwig Meyer, more frequently
in man than in woman. Mr. Woolner
made an exact model of one such
case, and sent me the accompanying
drawing (see fig. 2). These points
not only project inwards towards
the centre of the ear, but often
a little outwards from its plane,
so as to be visible when the
head is viewed from directly
in front or behind. They are
variable in size, and somewhat
in position, standing either
a little higher or lower; and
they sometimes occur on one ear
and not on the other. They are
not confined to mankind, for
I observed a case in one of the
spider-monkeys (Ateles beelzebuth)
in our Zoological Gardens; and
Mr. E. Ray Lankester informs
me of another case in a chimpanzee
in the gardens at Hamburg. The
helix obviously consists of the
extreme margin of the ear folded
inwards; and this folding appears
to be in some manner connected
with the whole external ear being
permanently pressed backwards.
In many monkeys, which do not
stand high in the order, as baboons
and some species of Macacus,*
the upper portion of the ear
is slightly pointed, and the
margin is not at all folded inwards;
but if the margin were to be
thus folded, a slight point would
necessarily project inwards towards
the centre, and probably a little
outwards from the plane of the
ear; and this I believe to be
their origin in many cases. On
the other hand, Prof. L. Meyer,
in an able paper recently published,*(2)
maintains that the whole case
is one of mere variability; and
that the projections are not
real ones, but are due to the
internal cartilage on each side
of the points not having been
fully developed. I am quite ready
to admit that this is the correct
explanation in many instances,
as in those figured by Prof.
Meyer, in which there are several
minute points, or the whole margin
is sinuous. I have myself seen,
through the kindness of Dr. L.
Down, the ear of a microcephalus
idiot, on which there is a projection
on the outside of the helix,
and not on the inward folded
edge, so that this point can
have no relation to a former
apex of the ear. Nevertheless
in some cases, my original view,
that the points are vestiges
of the tips of formerly erect
and pointed ears, still seems
to me probable. I think so from
the frequency of their occurrence,
and from the general correspondence
in position with that of the
tip of a pointed ear. In one
case, of which a photograph has
been sent me, the projection
is so large, that supposing,
in accordance with Prof. Meyer's
view, the ear to be made perfect
by the equal development of the
cartilage throughout the whole
extent of the margin, it would
have covered fully one-third
of the whole ear. Two cases have
been communicated to me, one
in North America, and the other
in England, in which the upper
margin is not at all folded inwards,
but is pointed, so that it closely
resembles the pointed ear of
an ordinary quadruped in outline.
In one of these cases, which
was that of a young child, the
father compared the ear with
the drawing which I have given*(3)
of the ear of a monkey, the Cynopithecus
niger, and says that their outlines
are closely similar. If, in these
two cases, the margin had been
folded inwards in the normal
manner, an inward projection
must have been formed. I may
add that in two other cases the
outline still remains somewhat
pointed, although the margin
of the upper part of the ear
is normally folded inwards- in
one of them, however, very narrowly.
The following woodcut (see fig.
3) is an accurate copy of a photograph
of the foetus of an orang (kindly
sent me by Dr. Nitsche), in which
it may be seen how different
the pointed outline of the ear
is at this period from its adult
condition, when it bears a close
general resemblance to that of
man. It is evident that the folding
over of the tip of such an ear,
unless it chang greatly during
its further development, would
give rise to a point projecting
inwards. On the whole, it still
seems to me probable that the
points in question are in some
cases, both in man and apes,
vestiges of a former condition.
* See also some remarks, and
the drawings of the ears of the
Lemuroidea, in Messrs. Murie
and Mivart's excellent paper
in Transactions of the Zoological
Society, vol. vii., 1869, pp.
6 and 90.
*(2) Uber das
Darwin'sche Spitzohr," Archiv
fur Path. Anst. und Phys., 1871,
p. 485.
*(3) The Expression of the Emotions,
p. 136.
The nictitating membrane, or
third eyelid, with its accessory
muscles and other structures,
is especially well developed
in birds, and is of much functional
importance to them, as it can
be rapidly drawn across the whole
eyeball. It is found in some
reptiles and amphibians, and
in certain fishes, as in sharks.
It is fairly well developed in
the two lower divisions of the
mammalian series, namely, in
the Monotremata and marsupials,
and in some few of the higher
mammals, as in the walrus. But
in man, the Quadrumana, and most
other mammals, it exists, as
is admitted by all anatomists,
as a mere rudiment, called the
semilunar fold.*
* Muller's Elements of Physiology,
Eng. translat., 1842, vol. ii.,
p. 1117. Owen, Anatomy of Vertebrates,
vol. iii., p. 260; ibid., on
the walrus, Proceedings of the
Zoological Society, November
8, 1854. See also R. Knox, Great
Artists and Anatomists, p. 106.
This rudiment apparently is somewhat
larger in Negroes and Australians
than in Europeans, see Carl Vogt,
Lectures on Man, Eng. translat.,
p. 129.
The sense of
smell is of the highest importance
to the greater
number of mammals- to some, as
the ruminants, in warning them
of danger; to others, as the
Carnivora, in finding their prey;
to others, again, as the wild
boar, for both purposes combined.
But the sense of smell is of
extremely slight service, if
any, even to the dark coloured
races of men, in whom it is much
more highly developed than in
the white and civilised races.*
Nevertheless it does not warn
them of danger, nor guide them
to their food; nor does it prevent
the Esquimaux from sleeping in
the most fetid atmosphere, nor
many savages from eating half-putrid
meat. In Europeans the power
differs greatly in different
individuals, as I am assured
by an eminent naturalist who
possesses this sense highly developed,
and who has attended to the subject.
Those who believe in the principle
of gradual evolution, will not
readily admit that the sense
of smell in its present state
was originally acquired by man,
as he now exists. He inherits
the power in an enfeebled and
so far rudimentary condition,
from some early progenitor, to
whom it was highly serviceable,
and by whom it was continually
used. In those animals which
have this sense highly developed,
such as dogs and horses, the
recollection of persons and of
places is strongly associated
with their odour; and we can
thus perhaps understand how it
is, as Dr. Maudsley has truly
remarked,*(2) that the sense
of smell in man "is singularly
effective in recalling vividly
the ideas and images of forgotten
scenes and places."
* The account
given by Humboldt of the power
of smell possessed
by the natives of South America
is well known, and has been confirmed
by others. M. Houzeau (Etudes
sur les Facultes Mentales, &c.,
tom. i., 1872, p. 91) asserts
that he repeatedly made experiments,
and proved that Negroes and Indians
could recognise persons in the
dark by their odour. Dr. W. Ogle
has made some curious observations
on the connection between the
power of smell and the colouring
matter of the mucous membrane
of the olfactory region as well
as of the skin of the body. I
have, therefore, spoken in the
text of the dark-coloured races
having a finer sense of smell
than the white races. See his
paper, Medico-Chirurgical Transactions,
London, vol. liii., 1870, p.
276.
*(2) The Physiology and Pathology
of Mind, 2nd ed., 1868, p. 134.
Man differs
conspicuously from all the
other primates in being
almost naked. But a few short
straggling hairs are found over
the greater part of the body
in the man, and fine down on
that of a woman. The different
races differ much in hairiness;
and in the individuals of the
same race the hairs are highly
variable, not only in abundance,
but likewise in position: thus
in some Europeans the shoulders
are quite naked, whilst in others
they bear thick tufts of hair.*
There can be little doubt that
the hairs thus scattered over
the body are the rudiments of
the uniform hairy coat of the
lower animals. This view is rendered
all the more probable, as it
is known that fine, short, and
pale-coloured hairs on the limbs
and other parts of the body,
occasionally become developed
into "thickset, long, and rather
coarse dark hairs," when abnormally
nourished near old-standing inflamed
surfaces.*(2)
* Eschricht, "Uber die Richtung
der Haare am menschlichen Korper," Muller's
Archiv fur Anat. und Phys., 1837,
s. 47. I shall often have to
refer to this very curious paper.
*(2) Paget, Lectures on Surgical
Pathology, 1853, vol. i., p.
71.
I am informed by Sir James Paget
that often several members of
a family have a few hairs in
their eyebrows much longer than
the others; so that even this
slight peculiarity seems to be
inherited. These hairs, too,
seem to have their representatives;
for in the chimpanzee, and in
certain species of Maeacus, there
are scattered hairs of considerable
length rising from the naked
skin above the eyes, and corresponding
to our eyebrows; similar long
hairs project from the hairy
covering of the superciliary
ridges in some baboons.
The fine wool-like hair, or
so-called lanugo, with which
the human foetus during the sixth
month is thickly covered, offers
a more curious case. It is first
developed, during the fifth month,
on the eyebrows and face, and
especially round the mouth, where
it is much longer than that on
the head. A moustache of this
kind was observed by Eschricht*
on a female foetus; but this
is not so surprising a circumstance
as it may at first appear, for
the two sexes generally resemble
each other in all external characters
during an early period of growth.
The direction and arrangement
of the hairs on all parts of
the foetal body are the same
as in the adult, but are subject
to much variability. The whole
surface, including even the forehead
and ears, is thus thickly clothed;
but it is a significant fact
that the palms of the hands and
the soles of the feet are quite
naked, like the inferior surfaces
of all four extremities in most
of the lower animals. As this
can hardly be an accidental coincidence,
the woolly covering of the foetus
probably represents the first
permanent coat of hair in those
mammals which are born hairy.
Three or four cases have been
recorded of persons born with
their whole bodies and faces
thickly covered with fine long
hairs; and this strange condition
is strongly inherited, and is
correlated with an abnormal condition
of the teeth.*(2) Prof. Alex.
Brandt informs me that he has
compared the hair from the face
of a man thus characterised,
aged thirty-five, with the lanugo
of a foetus, and finds it quite
similar in texture; therefore,
as he remarks, the case may be
attributed to an arrest of development
in the hair, together with its
continued growth. Many delicate
children, as I have been assured
by a surgeon to a hospital for
children, have their backs covered
by rather long silky hairs; and
such cases probably come under
the same head.
* Eschricht, ibid., ss. 40,
47.
*(2) See my Variation of Animals
and Plants under Domestication,
vol. ii., p. 327. Prof. Alex.
Brandt has recently sent me an
additional case of a father and
son, born in Russia, with these
peculiarities. I have received
drawings of both from Paris.
It appears as
if the posterior molar or wisdom-teeth
were tending
to become rudimentary in the
more civilised races of man.
These teeth are rather smaller
than the other molars, as is
likewise the case with the corresponding
teeth in the chimpanzee and orang;
and they have only two separate
fangs. They do not cut through
the gums till about the seventeenth
year, and I have been assured
that they are much more liable
to decay, and are earlier lost
than the other teeth; but this
is denied by some eminent dentists.
They are also much more liable
to vary, both in structure and
in the period of their development,
than the other teeth.* In the
Melanian races, on the other
hand, the wisdom-teeth are usually
furnished with three separate
fangs, and are generally sound;
they also differ from the other
molars in size, less than in
the Caucasian races.*(2) Prof.
Schaaffhausen accounts for this
difference between the races
by "the posterior dental portion
of the jaw being always shortened" in
those that are civilised,*(3)
and this shortening may, I presume,
be attributed to civilised men
habitually feeding on soft, cooked
food, and thus using their jaws
less. I am informed by Mr. Brace
that it is becoming quite a common
practice in the United States
to remove some of the molar teeth
of children, as the jaw does
not grow large enough for the
perfect development of the normal
number.*(4)
* Dr. Webb, "Teeth in Man and
the Anthropoid Apes," as quoted
by Dr. C. Carter Blake in Anthropological
Review, July, 1867, p. 299.
*(2) Owen, Anatomy of Vertebrates,
vol. iii., pp. 320, 321, and
325.
*(3) "On the Primitive Form
of the Skull," Eng. translat.,
in Anthropological Review, Oct.,
1868, p. 426.
*(4) Prof. Montegazza writes
to me from Florence, that he
has lately been studying the
last molar teeth in the different
races of man, and has come to
the same conclusion as that given
in my text, viz., that in the
higher or civilised races they
are on the road towards atrophy
or elimination.
With respect to the alimentary
canal, I have met with an account
of only a single rudiment, namely
the vermiform appendage of the
caecum. The caecum is a branch
or diverticulum of the intestine,
ending in a cul-de-sac, and is
extremely long in many of the
lower vegetable-feeding mammals.
In the marsupial koala it is
actually more than thrice as
long as the whole body.* It is
sometimes produced into a long
gradually-tapering point, and
is sometimes constricted in parts.
It appears as if, in consequence
of changed diet or habits, the
caecum had become much shortened
in various animals, the vermiform
appendage being left as a rudiment
of the shortened part. That this
appendage is a rudiment, we may
infer from its small size, and
from the evidence which Prof.
Canestrini*(2) has collected
of its variability in man. It
is occasionally quite absent,
or again is largely developed.
The passage is sometimes completely
closed for half or two-thirds
of its length, with the terminal
part consisting of a flattened
solid expansion. In the orang
this appendage is long and convoluted:
in man it arises from the end
of the short caecum, and is commonly
from four to five inches in length,
being only about the third of
an inch in diameter. Not only
is it useless, but it is sometimes
the cause of death, of which
fact I have lately heard two
instances: this is due to small
hard bodies, such as seeds, entering
the passage, and causing inflammation.*(3)
* Owen, Anatomy of Vertebrates,
vol. iii., pp 416, 434, 441.
*(2) Annuario della Soc. d.
Nat. Modena, 1867, p. 94.
*(3) M. C. Martins
("De l'Unite
Organique," in Revue des Deux
Mondes, June 15, 1862, p. 16)
and Haeckel (Generelle Morphologie,
B. ii., s. 278), have both remarked
on the singular fact of this
rudiment sometimes causing death.
In some of the lower Quadrumana,
in the Lemuridae and Carnivora,
as well as in many marsupials,
there is a passage near the lower
end of the humerus, called the
supra-condyloid foramen, through
which the great nerve of the
fore limb and often the great
artery pass. Now in the humerus
of man, there is generally a
trace of this passage, which
is sometimes fairly well developed,
being formed by a depending hook-like
process of bone, completed by
a band of ligament. Dr. Struthers,*
who has closely attended to the
subject, has now shewn that this
peculiarity is sometimes inherited,
as it has occurred in a father,
and in no less than four out
of his seven children. When present,
the great nerve invariably passes
through it; and this clearly
indicates that it is the homologue
and rudiment of the supra-condyloid
foramen of the lower animals.
Prof. Turner estimates, as he
informs me, that it occurs in
about one per cent of recent
skeletons. But if the occasional
development of this structure
in man is, as seems probable,
due to reversion, it is a return
to a very ancient state of things,
because in the higher Quadrumana
it is absent.
* With respect to inheritance,
see Dr. Struthers in the Lancet,
Feb. 15, 1873, and another important
paper, ibid., Jan. 24, 1863,
p. 83. Dr. Knox, as I am informed,
was the first anatomist who drew
attention to this peculiar structure
in man; see his Great Artists
and Anatomists, p. 63. See also
an important memoir on this process
by Dr. Gruber, in the Bulletin
de l'Acad. Imp. de St. Petersbourg,
tom. xii., 1867, p. 448.
There is another
foramen or perforation in the
humerus, occasionally
present in man, which may be
called the inter-condyloid. This
occurs, but not constantly, in
various anthropoid and other
apes,* and likewise in many of
the lower animals. It is remarkable
that this perforation seems to
have been present in man much
more frequently during ancient
times than recently. Mr. Busk*(2)
has collected the following evidence
on this head: Prof. Broca "noticed
the perforation in four and a
half per cent of the arm-bones
collected in the 'Cimetiere,
du Sud,' at Paris; and in the
Grotto of Orrony, the contents
of which are referred to the
Bronze period, as many as eight
humeri out of thirty-two were
perforated; but this extraordinary
proportion, he thinks, might
be due to the cavern having been
a sort of 'family vault.' Again,
M. Dupont found thirty per cent
of perforated bones in the caves
of the Valley of the Lesse, belonging
to the Reindeer period; whilst
M. Leguay, in a sort of dolmen
at Argenteuil, observed twenty-five
per cent to be perforated; and
M. Pruner-Bey found twenty-six
per cent in the same condition
in bones from Vaureal. Nor should
it be left unnoticed that M.
Pruner-Bey states that this condition
is common in Guanche skeletons." It
is an interesting fact that ancient
races, in this and several other
cases, more frequently present
structures which resemble those
of the lower animals than do
the modern. One chief cause seems
to be that the ancient races
stand somewhat nearer in the
long line of descent to their
remote animal-like progenitors.
* Mr. St. George Mivart, Transactions
Phil. Soc., 1867, p. 310.
*(2) "On the Caves of Gibraltar," Transactions
of the International Congress
of Prehistoric Archaeology, Third
Session, 1869, p. 159. Prof.
Wyman has lately shewn (Fourth
Annual Report, Peabody Museum,
1871, p. 20), that this perforation
is present in thirty-one per
cent of some human remains from
ancient mounds in the Western
United States, and in Florida.
It frequently occurs in the negro.
In man, the os coccyx, together
with certain other vertebrae
hereafter to be described, though
functionless as a tail, plainly
represent this part in other
vertebrate animals. At an early
embryonic period it is free,
and projects beyond the lower
extremities; as may be seen in
the drawing (see fig. 1) of a
human embryo. Even after birth
it has been known, in certain
rare and anomalous cases,* to
form a small external rudiment
of a tail. The os coccyx is short,
usually including only four vertebrae,
all anchylosed together: and
these are in a rudimentary condition,
for they consist, with the exception
of the basal one, of the centrum
alone.*(2) They are furnished
with some small muscles; one
of which, as I am informed by
Prof. Turner, has been expressly
described by Theile as a rudimentary
repetition of the extensor of
the tail, a muscle which is so
largely developed in many mammals.
* Quatrefages has lately collected
the evidence on this subject.
Revue des Cours Scientifiques,
1867-1868, p. 625. In 1840 Fleischmann
exhibited a human foetus bearing
a free tail, which, as is not
always the case, included vertebral
bodies; and this tail was critically
examined by the many anatomists
present at the meeting of naturalists
at Erlangen (see Marshall in
Niederland. Archiv fur Zoologie,
December, 1871).
*(2) Owen, On the Nature of
Limbs, 1849, p. 114.
The spinal cord in man extends
only as far downwards as the
last dorsal or first lumbar vertebra;
but a thread-like structure (the
filum terminale) runs down the
axis of the sacral part of the
spinal canal, and even along
the back of the coccygeal bones.
The upper part of this filament,
as Prof. Turner informs me, is
undoubtedly homologous with the
spinal cord; but the lower part
apparently consists merely of
the pia mater, or vascular investing
membrane. Even in this case the
os coccyx may be said to possess
a vestige of so important a structure
as the spinal cord, though no
longer enclosed within a bony
canal. The following fact, for
which I am also indebted to Prof.
Turner, shews how closely the
os coccyx corresponds with the
true tail in the lower animals:
Luschka has recently discovered
at the extremity of the coccygeal
bones a very peculiar convoluted
body, which is continuous with
the middle sacral artery; and
this discovery led Krause and
Meyer to examine the tail of
a monkey (Maeacus), and of a
cat, in both of which they found
a similarly convoluted body,
though not at the extremity.
The reproductive system offers
various rudimentary structures;
but these differ in one important
respect from the foregoing cases.
Here we are not concerned with
the vestige of a part which does
not belong to the species in
an efficient state, but with
a part efficient in the one sex,
and represented in the other
by a mere rudiment. Nevertheless,
the occurrence of such rudiments
is as difficult to explain, on
the belief of the separate creation
of each species, as in the foregoing
cases. Hereafter I shall have
to recur to these rudiments,
and shall shew that their presence
generally depends merely on inheritance,
that is, on parts acquired by
one sex having been partially
transmitted to the other. I will
in this place only give some
instances of such rudiments.
It is well known that in the
males of all mammals, including
man, rudimentary mammae exist.
These in several instances have
become well developed, and have
yielded a copious supply of milk.
Their essential identity in the
two sexes is likewise shewn by
their occasional sympathetic
enlargement in both during an
attack of the measles. The vesicula
prostatica, which has been observed
in many male mammals, is now
universally acknowledged to be
the homologue of the female uterus,
together with the connected passage.
It is impossible to read Leuckart's
able description of this organ,
and his reasoning, without admitting
the justness of his conclusion.
This is especially clear in the
case of those mammals in which
the true female uterus bifurcates,
for in the males of these the
vesicula likewise bifurcates.*
Some other rudimentary structures
belonging to the reproductive
system might have been here adduced.*(2)
* Leuckart, in Todd's Cyclopaedia
of Anatomy, 1849-52, vol. iv.,
p. 1415. In man this organ is
only from three to six lines
in length, but, like so many
other rudimentary parts, it is
variable in development as well
as in other characters.
*(2) See, on this subject, Owen,
Anatomy of Vertebrates, vol.
iii., pp. 675, 676, 706.
The bearing
of the three great classes
of facts now given is
unmistakeable. But it would be
superfluous fully to recapitulate
the line of argument given in
detail in my Origin of Species.
The homological construction
of the whole frame in the members
of the same class is intelligible,
if we admit their descent from
a common progenitor, together
with their subsequent adaptation
to diversified conditions. On
any other view, the similarity
of pattern between the hand of
a man or monkey, the foot of
a horse, the flipper of a seal,
the wing of a bat, &c., is utterly
inexplicable.* It is no scientific
explanation to assert that they
have all been formed on the same
ideal plan. With respect to development,
we can clearly understand, on
the principle of variation supervening
at a rather late embryonic period,
and being inherited at a corresponding
period, how it is that the embryos
of wonderfully different forms
should still retain, more or
less perfectly, the structure
of their common progenitor. No
other explanation has ever been
given of the marvellous fact
that the embryos of a man, dog,
seal, bat, reptile, &c., can
at first hardly be distinguished
from each other. In order to
understand the existence of rudimentary
organs, we have only to suppose
that a former progenitor possessed
the parts in question in a perfect
state, and that under changed
habits of life they became greatly
reduced, either from simple disuse,
or through the natural selection
of those individuals which were
least encumbered with a superfluous
part, aided by the other means
previously indicated.
* Prof. Bianconi,
in a recently published work,
illustrated by
admirable engravings (La Theorie
Darwinienne et la creation dite
independante, 1874), endeavours
to show that homological structures,
in the above and other cases,
can be fully explained on mechanical
principles, in accordance with
their uses. No one has shewn
so well, how admirably such structures
are adapted for their final purpose;
and this adaptation can, as I
believe, be explained through
natural selection. In considering
the wing of a bat, he brings
forward (p. 218) what appears
to me (to use Auguste Comte's
words) a mere metaphysical principle,
namely, the preservation "in
its integrity of the mammalian
nature of the animal." In only
a few cases does he discuss rudiments,
and then only those parts which
are partially rudimentary, such
as the little hoofs of the pig
and ox, which do not touch the
ground; these he shows clearly
to be of service to the animal.
It is unfortunate that he did
not consider such cases as the
minute teeth, which never cut
through the jaw in the ox, or
the mammae of male quadrupeds,
or the wings of certain beetles,
existing under the soldered wing-covers,
or the vestiges of the pistil
and stamens in various flowers,
and many other such cases. Although
I greatly admire Prof. Bianconi's
work, yet the belief now held
by most naturalists seems to
me left unshaken, that homological
structures are inexplicable on
the principle of mere adaptation.
Thus we can understand how it
has come to pass that man and
all other vertebrate animals
have been constructed on the
same general model, why they
pass through the same early stages
of development, and why they
retain certain rudiments in common.
Consequently we ought frankly
to admit their community of descent:
to take any other view, is to
admit that our own structure,
and that of all the animals around
us, is a mere snare laid to entrap
our judgment. This conclusion
is greatly strengthened, if we
look to the members of the whole
animal series, and consider the
evidence derived from their affinities
or classification, their geographical
distribution and geological succession.
It is only our natural prejudice,
and that arrogance which made
our forefathers declare that
they were descended from demigods,
which leads us to demur to this
conclusion. But the time will
before long come, when it will
be thought wonderful that naturalists,
who were well acquainted with
the comparative structure and
development of man, and other
mammals, should have believed
that each was the work of a separate
act of creation. |