EVIDENCE FROM ARRANGEMENT OF HAIR.
_Ex Uno Disce Omnes._
The singular arrangement of hair on the forearm of man is the subject
of some curious statements by Darwin, Wallace and Romanes, and these
suggested to me twenty years ago the following line of thought. To many
minds the text will appear a humble one, but it opens many avenues of
inquiry.
These three illustrious men are all more or less inaccurate and
incomplete in their descriptions of the hair on man’s forearm, though
Romanes[42] gives a drawing which supplements his written account.
They looked upon it as a vestige of the pattern of hair on the forearm
of existing anthropoid apes, especially the orang, in whom its
fully-developed form was an adaptation governed by Natural Selection.
Of the three, Wallace is the most uncompromising on behalf of this
view, Romanes rather accepts it _en passant_, and Darwin in a long
passage[43] adopts it with some reserve and his usual respect for the
work of his great co-worker, as the most probable explanation of a fact
which lay heavy on his scientific conscience. Indeed, for all these
great men it was a _crux_, though Romanes, with his Lamarckian views,
need not have found much difficulty with an alternative account of
it.[44]
[42] _Darwin and after Darwin_, Vol. 1, p. 90.
[43] _The Descent of Man_, Chap. VI., p, 151.
[44] I may remark that Darwin seems at an earlier date to have made a
very curious suggestion in this connection, for Hartmann, in his work
on Anthropoid Apes, p. 99, quotes him as saying: “We should, however,
bear in mind that the attitude of an animal may perhaps be in part
determined by the direction of the hair; and not the direction of the
hair by the attitude,” a notion so obviously untenable that it does
not appear in the second edition of _The Descent of Man_, 1896.
At the time when these statements were made, the lineal ancestors of
man were much more definite personages than they are now, as Arthur,
the legendary Celtic hero, was formerly held to be an historical
personage more than is the case now. These ancestors were generally
believed then to be found among the four existing anthropoid apes.
The picture of our ancestor among the apes, as given by Wallace, in
connection with this state of the hair on his forearm, represents
him as spending much of his time like the gorilla, who, according to
Livingstone, “sits in pelting rain with his hands over his head.” He
would no doubt find the thatch-like arrangement of the hair a tolerably
efficient umbrella, but one may doubt very much if so clever a denizen
of the tropics would fail to find under the great branches of trees, in
a tropical forest, a better covering and one more like the roofs of our
houses. But when we cannot find a roof to our heads we--and the orang
or gorilla--naturally employ a substitute, and not otherwise. Be that
as it may, it is doubtful if the thatch of his forearms would supply
him with that survival value on which the theory of Selection depends,
to say nothing of the fact that in its incipient stage the reversal of
the slope of hair, inherited from the lemur stock, would be trivial and
useless.
But one must ask: “Did man’s Simian ancestor really loaf away so much
of his time in this dull manner? and was the running-off of rain so
frequent and imperative a need as to make him set to work to invent
this special adaptation?”
After some millions of years have passed since his day we are not in a
position to go beyond speculations, and this one seems barely credible,
moreover, it is quite unnecessary, as certain following facts will show.
Steps of the Inquiry.
Having expounded the text and its context, I would mention that in
1897 I came across these views of biologists as to the very strange
arrangement of hair on man’s forearm, and was struck with the
inadequacy of the theory of Darwin, Wallace and Romanes to account for
the state of things which every man can find, if he looks for it, on
his own forearm. I examined a large number of apes and monkeys so as to
test the theory, and the results were published in _Nature_, Vol. 55,
under the title “Certain vestigial characters in Man.” Suffice it to
say that from the evidence I brought forward one had to choose between
two heresies: either to deny the Simian ancestry of man or to affirm
the inheritance of some acquired characters; and I chose the latter.
The choice of “evils” or heresies which had to be made then will serve
as an introduction to all that follows.
This article was followed by a paper at the Zoological Society of
London on “The Hair-Slope in certain Typical Mammals,” and after this
came a paper at the same Society, giving evidence and reason why
certain patterns of hair in some mammals should rank as specific
characters. Various other papers at the Anatomical Society of Great
Britain and Ireland were read and published and others at the
Zoological Society, in which different regions of the hairy coat of
man and lower mammals were dealt with. In 1903 the whole subject of
the Direction of Hair in Animals and Man was treated in a book freely
illustrated.
I then followed the advice of Horace and left the subject alone for
nine years, during which time my further observations and reflections
served but to confirm, except in two or three unimportant details, the
results and conclusions in the book and papers of an earlier date.
The connection between the habits of an animal and the distribution
of its hairy coat were always cropping up, and I saw then and see now
no possible explanation of the connection than that the former is the
efficient cause of the latter.
How the Hair is Arranged on the Forearm.
Returning now to the text, the remarkable arrangement of hair on man’s
forearm, attention may be directed to the accompanying figure of the
forearm of a lemur, an ape and man, in which the extensor or back view
of this limb-segment is shown, the heavy “war-arrows” being employed
to direct the attention of the reader to the main lines in which the
hair-streams flow. The front or flexor surfaces in the lemur and
ape are not shown because they are precisely like the corresponding
back surfaces, and the flexor surface in man is shown in the figure.
The figures are so much like diagrams that a very little detailed
description will suffice. For the examination of the hair on man’s
forearm the best subject is a dark-haired youth, and it is easily
traced, though in any hairy subject it can be shown up well by placing
the forearm in water for a minute and allowing the water to drain
off. The normal and congenital hair-slope on the forearm is then well
displayed.
On the front surface of man’s forearm the hairs point away from the
elbow and divide in the middle of the surface into two streams, one
passing to the outer and the other to the inner border in a downward
gentle curve, and they join the streams of hair on the back surface. In
this pattern there is nothing very peculiar, for it is shared by many
monkeys.
When the back surface is examined it is found to present an arrangement
of the hair which is _unique_ among hairy mammals. The figure shows the
eccentric course taken by the hair on the back surface. In the centre,
exactly along the extensor border of the ulna, from the wrist to the
point of the elbow, the hair-stream has been bold enough to turn
straight _upwards_ in a narrow line, and it was here that our three
great leaders saw their chance of claiming for Selection a tiny bit
of territory, a kind of Duchy of Luxembourg between two great States,
though, as I proceed to show, the claim is disallowed and untenable.
[Illustration: Fig 1.--Arrangement of Hair on the Forearm.]
In the ape the hairs of the forearm are much longer and thicker than
those of man, and both on the front and back all point _from the wrist
to the elbow_.
In the lemur all the hairs point _from the elbow to the wrist_.
In the products of Nature there are no freaks, or impish tricks
performed, and it is not for nothing she does her work. Every one of
them asks for and should receive an explanation consistent with fact
and reason, and here comes in the need for studying, as one may, the
broad outlines of man’s ancestry. His ancestor being now sought in an
earlier and more generalized stock than that of the four genera of
anthropoid apes known to us, the most instructive and safest line to
take is to trace him back to the stock lemur, who remains to-day among
the most Chinese or unchanging of known mammals. In his illuminating
work, _Prehistoric Man and History_, Professor Scott Elliott adopts an
excellent term, “lemur-monkey-man,” to sum up, without missing links,
the long ancestry of man. I take the liberty of adapting this term more
closely to the present inquiry and use that of _lemur-ape-man_ instead,
for whatever may be the relation of man to present apes some ape-like
ancestors enter into his genealogical tree.[45] For my purpose the
monkey is less useful because his hair-slope differs so little from
that of lemurs, whereas apes have made for themselves a very remarkable
position as regards the hair of their forearms. Our series of animals
for study is then well represented by the lemur-ape-man--hypothetical,
necessary and serviceable. Through all the immense stretch of time
occupied in this process of descent there has been ample opportunity
for the lemur to change his fashion to that of the ape, and the latter
to change to the present fashion of man.
[45] This was written before the publication of Professor
Woods-Jones’ book _Arboreal Man_.
This simple arrangement of the lemur’s hair is common to that of all
the more primitive long-bodied mammals, of which an otter is a good
example, and I venture, greatly daring, to call this the normal slope
of hair. Somewhere and somehow in the human tree there has appeared
a total reversal of the lemur-type; the stock of apes acquired a new
fashion, and gradually discarded altogether their ancient inheritance,
beginning their innovation perhaps, with _Dryopithecus fontani_ in the
Miocene Age.
The Dynamics of Hair-Pattern.
There are a few well-known facts which it is necessary to bear in mind
if one is endeavouring to understand the mode of origin and order
of the events before us. The hairy coat of a mammal is composed of
individual hairs of varying length, colour and thickness, each being
rooted in a tiny pit in the skin and growing from a papilla at its
base. As the hair grows, its free end is pushed away from the papilla
at the rate of one inch in two months. This is the rate in man’s hair,
and it is probably greater in the case of lower mammals on account
of the greater importance and physiological activity of their hairy
coat than in man’s. But one inch in two months is a close enough
calculation. Here, then, is a structure which grows throughout the
whole life of the animal, and has to dispose itself somehow on the
surface of the skin. It does this _in the line of least resistance_,
and to trace this line is the Alpha and Omega of the present inquiry.
There is a conception of much value in understanding the dynamics of
the distribution of hair, and that is to view the hair of mammals as
composed of certain streams. As in every illustration, this conception
may be challenged because of some difference the critic may find
between these streams and a stream of fluid. It certainly does not
leave its bed as do the component parts of a river, a glacier or molten
lava, for the base of the hair is fixed. But it will serve, and is
at least not more open to objection than certain useful metaphors in
biology as when the genealogy of man and animals is pictured as a tree,
or the living things of the earth as a “web of life.” It is, then, as
_streams moving at the rate of one inch in two months in the lines of
least resistance_ that I propose to discuss the animal hair and its
diverse patterns and offer no further apology for doing so. Just as
in the cases of a stream of water with varying banks and rocks in its
course, or a glacier with its mountain-sides and sinuous valleys, or a
stream of lava with small projecting surfaces of a mountain, our stream
of hair flows on, hindered only by adequate obstructions.
Yet another conception from the region of metaphor must be mentioned.
It is one which will commend itself to every mind which has been
steeped in thoughts of warfare for five years. We are all soldiers now;
we think in terms of military affairs. In the case of our hair-streams
there are in many regions two forces directly opposed to one another,
others in which no struggle has yet occurred, as, in the Great War,
Italy was not at one period at open war with Germany.
Between the opposing forces in our small battle-field of the hairy
coat there have been waged battles to which those of Mukden, Verdun,
the Somme and Arras, are not to be compared in point of time. They
are but as one day to a thousand years. On one side of the conflict
in our present chosen field the ancient primitive type of the lemur
has remained entrenched for some millions of years, until there arose
new forces in its descendants on the other side and this changed the
war of positions into one of movement. It was indeed “a contemptible
little army” which came forward to oppose the ancient barbarian
forces of the lemur, long prepared and organised, and these new
armies fought under the banner, Habit. In the slowly-formed patterns
in many types of mammals we have records of the treaties made after
these long struggles and the rectifications of frontier which became
necessary. The critic may call these “battles of kites and crows,”
and ask What war correspondents were allowed to describe them; but a
battle, whether great or small, long or short, is important to the
parties concerned, and it is open to us to “reconstruct” the facts of
the battle as do the historians on their part, for example, Sir James
Ramsay the battle of Agincourt--with tolerable verisimilitude. But in
science, especially geological science, the process of reconstruction
is much more ambitious and bold than any that is here attempted. Who
has not been fascinated, if he has read Sir E. Ray Lankester’s work
on Extinct Animals, by the skill and daring with which he conveys to
us a vivid idea of the form and mode of life, with scanty data, of
the extinct Moa of New Zealand, the great Pterodactyle, Pteranodon,
or the Diprotodon of Owen--“the probable appearance in life” of these
uncanny but very real inhabitants of the earth in days long past. How
skilfully did Owen from a piece of bone seven inches long, sent to
him by a gentleman in New Zealand sixty years ago, pronounce it to be
a part of the thigh-bone of a bird like an ostrich, and then after a
few years had passed, confirmed it by more bones of the skeleton, till
the large Moa, extinguished 600 or 700 years ago by the Maoris, lived
again before us--an historical personage; or how by the examination of
the skull and most of its skeleton the giant marsupial from Australia,
Diprotodon, was resuscitated and admired; or again, how from the bones
of the arms, shoulder-girdle and fingers was built up the strange body
of Pteranodon, the great flying dragon. All of which is the legitimate
and approved business of biologists and palæontologists, and this
digression is made here to show that my line of treatment of a little
subject agrees with that in a greater one; nay, it even proceeds in
its explanations of events on the ever valuable principle of Lyell in
a still greater one without which to-day geology would be a thing of
naught, that is, the principle of _explaining changes in the surface of
the earth by reference to causes now in action_. The objection that one
subject is very great and the other very small is not valid; for one as
much as the other there are millions of years to be had for the asking.
Who in these days hesitates to talk and try to think in millions?--tens
of millions of men, millions of soldiers, millions upon millions of
money, millions of bacteria in vaccines and millions of money belonging
to other people disposed of by the new spendthrift Minister?
From Lemur to Ape.
Returning now to our Eocene lemur we must remind ourselves of the
problem before his simple mind and those of his Simian descendants. How
was he to change so greatly the direction of the hair on his forearm
(Fig. 1) till it should turn right about face and imitate those great
German “victories” of Hindenburg, well called Marshal Rückwarts? The
problem lies open in the Figure and receiving no aid from Selection or
survival of the fittest, in this little effort, he had to fall back on
the eternal and tedious force of habit and use. I am afraid if here I
were interrupted by some critic, more learned than wise, by a summary
demand on the part of Selection for its share in the result, I should
be tempted to reply with the word Φλυαρια employed by George Borrow,
forbearing to give the translation of the reply as he gives it. Anyhow,
it is a case in which to “listen politely and change the subject.”
Here comes in the aspect of strife between primitive and new
obstructing forces in a little hair-stream. The lemur lives in trees
and carries on a stealthy nocturnal business, moving on all fours in
quest of his daily bread, and no external force or new habit avails to
modify the hair-slope on his forearms, and so it remains until some
primitive form of monkey, gradually evolving into a primitive ape,
brings into the family new habits and customs. Other men and other
manners appear in the Miocene Age. Our supposed Dryopithecus fontani
becomes more upright in his bodily, and perhaps his moral habits,
and spends an increasing amount of his leisure time in the sitting
posture; his hands are frequently grasping a bough as he sits and
reflects, it may be in a man-ward direction, or, as is more likely, on
his last meal of nuts and fruits. But he did not spend quite so much
time as Wallace and others think in this futile attitude, for he knew
in his way as much as the modern bachelor does, of making his posture
comfortable and restful when he was not out at work, and he varied
his plans by resting his forearms on his thigh, crouched up and cosy,
and doubtless slept much in this attitude. All these bold departures
from his lemur-ancestor’s habits had the necessary result of altering
the slope of his hair on the forearms, which was now growing as long
and coarse as we see it to-day in the orang. In course of milleniums
the ancient forces yielded to those of the new armies, and the once
normal slope became reversed in a way which shocked the conservative
lemurs of his day. It requires little imagination to see how the
lengthening thickening hairs on this limb-segment became changed in
their direction by friction against the opposing surfaces of the
thighs, by gravitation, and the frequent dripping of rain when they
were held up to grasp a bough. Here then we see at work new forces of
friction, pressure, gravitation and dripping of rain, turning endlessly
and slowly the lemur-fashion into the ape-fashion, with unlimited time
for their effectual action. In this stock of Man’s ancestry Selection
was taking care of the individual and Habit of the details of his
making--two truly harmonious partners.
From Ape to Man.
Another step, and a long one, has still to be taken from the
ape-fashion to that of man. Bearing in mind that the lemur-fashion has
been totally reversed by the ape it startles one to find that man in
his modern fashion has largely reverted to that of the lemur on the
front and sides of his forearm. This is clearly shown in Figure 1.
There also you see graphically recorded in the hair of the extensor
border of the ulna, a little _backward_ streak, a poor little legacy of
fifty pounds from the fortunes of many thousands once possessed by the
ape. From the present limited point of view, man is a veritable pauper,
and his possessions in this limb-segment may with some irony well be
called a “vestige.”
Professor Scott-Elliott in his book, _Prehistoric Man and His Story_,
p. 60, goes rather wide of the mark here in his graphic picture of our
rude ancestor and his hard life. He gives too strongly the idea of
him sitting asleep in raging gales, in driving rain which is neatly
conducted by the thatch of his hair off his skin. As far as it goes
this need not be questioned, as a matter of probability, but he states
far too broadly “The hair on the arm, even of those civilised men who
retain sufficient to trace the arrangement, turns down both upper
and forearm to the elbow”[46]--true as to the upper arm, but only
true of the forearm in a very narrow streak of hair over the extensor
surface of the ulna. The fact is that in every human being, not too
old, its course can be traced with a lens. He overlooks also from
this protective point of view the fact that the ape or early man, in
the position of rest he describes, would have very much the reverse
of protection from the “lie” of the hair on his thighs, for this is
towards the knee and is well calculated to catch the rain and conduct
it carefully, or let it run, into his groins. So the protection theory
(under the empire of Selection) is again in straits. But I must not
forget my self-denying ordinance alluded to in the Preface, but will
show how the ape fashion began to be modified into its present and
probably final form in man. Still further changes in the simple habits
of the earliest men became frequent, and fresh forces were organised in
our mimic battlefield. Gravitation gradually ceased to act as the hairs
became thinner and shorter. Friction and pressure changed their lines
of incidence with the increasing tendency of man to assume the upright
posture, for the surfaces exposed to pressure and friction were only
affected when the extensor surface or back of the forearm rested on
some supporting object, an attitude extremely common in man as we know
him now. Then came the opportunity of the primitive barbarian host, the
lemur fashion, by a prolonged counter-attack to recover on the greater
part of the forearm the ground lost millions of years before by the
ape, and then was engraved on the forearm of man the permanent treaty
which we have before us to-day.
[46] _Prehistoric Man and His Story_, p. 60
This small and apparently trivial battle-ground has been described at
what may seem undue length, but it is a miniature of the rise and fall
of little empires such as here engage our attention, and I make no
apology for this to the reader who has gone thus far with me, for, on
the principle of _ex uno disce omnes_, all that follows in other areas
of the hairy coat of mammals will be the clearer, and little repetition
will be needed.
NOTE.--Two terms have been used somewhat freely in this Introduction,
“vestige” and “normal,” and a few remarks upon them are not out of
place, for they are both somewhat ambiguous and apt to be carelessly
employed.
A vestige in biological writings is almost the exclusive property
of the Pan-Selectionists, and no one can doubt that on the one
hand it is a far more correct term than that of rudiment which
Darwin employed so freely, on the other that they have a perfectly
legitimate claim to it in a large number of obsolete structures of
animal forms. But vestiges, footsteps, footprints, have another and
equally correct meaning, even if less often thus employed, in the
fact that a vestige or footprint may just as well be a relic of
what the race and individuals have _done_, as a relic of what they
have _retained_ in the way of possession, and I submit that the
facts and arguments I have here advanced afford a valid claim to the
term “vestige” in the results of certain _doings_ on the part of
animals--as will appear later still more clearly.
The term “normal” is a fine field for dialectics, but neither
ordinary men nor scientific students can do their work without
its use, and yet it would have been an intellectual treat to
have heard how Huxley, for example, would have turned inside out
any opponent who chose to employ it to his dissatisfaction. In a
strictly-conducted tournament no evolutionary biologist would allow
its use--to his adversary. A norm for him exists only as one of
Professor Karl Pearson’s “conceptual counters,” a piece of mental
shorthand or hardly more than a _pis aller_. Among the fundamental
conceptions of organic evolution there is one which is almost a
truism, the doctrine of Heraclitus, πἁντα ρε̑ι, the everlasting flux
and change of Nature and her products. In strict logic, according
to what we all now believe, there is no possible norm. All that one
may do is to take stock at a certain epoch of evolution and label,
for our own convenience, some group, or organism or structure as
“normal”--and go on with our business, collecting some specimens,
calling them type-specimens, and putting them in books or cases in
the Natural History Museum--and then proceed to business.
The biological teacher in his class room says he must live, he must
have his tools for his work, to which the idle student replies under
his breath, “I do not see the necessity,” but then few students
are now idle, and this jibe does not sting any one! The examiner
must have his normal human anatomy, and would ruthlessly plough
any daring examinee who tried to sophisticate the meaning of the
term “normal.” I have often been struck with what I must call the
intellectual audacity of a most eminent leader in physical science
and mathematics, who is not unlike a certain great Church, which
grants nothing to her adversaries but is not averse from taking. In
his _Grammar of Science_, written with a pen dipped in hydrochloric
acid, Professor Karl Pearson four times over, and perhaps more,
has the courage to call the human brain in this twentieth century
“normal.” Has he never heard of the coming Superman of Mr. Bernard
Shaw and other prophets? Thinking _sub specie aeternitatis_ has he
here in the West, and at a certain small epoch of time, any right
to call the human brain “normal”? I can only long that there may be
more normal brains such as Professor Karl Pearson’s, and am almost
inclined to echo the prayer of Moses, “Would God all the Lord’s
people were [such] prophets”! These comments on the term “normal”
imply no complaint against its use, indeed are a claim for it, and I
deprecate very much that form of criticism known in boys’ schools,
domestic circles, and among politicians as the _tu quoque_ reply,
and I hope the few ambiguous terms used in this book will pass the
censor, and help the reader.