The Outline of Science, Vol. 1 (of 4)

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When all these lines of evidence are considered, they are seen to
converge in the conclusion that man is derived from a simian stock of
mammals. He is solidary with the rest of creation. To quote the closing
words of Darwin's _Descent of Man_:

We must, however, acknowledge, as it seems to me, that man with all
his noble qualities, with sympathy which feels for the most debased,
with benevolence which extends not only to other men but to the
humblest living creature, with his God-like intellect, which has
penetrated into the movements and constitution of the solar
system--with all these exalted powers--man still bears in his bodily
frame the indelible stamp of his lowly origin.

We should be clear that this view does not say more than that man sprang
from a stock common to him and to the higher apes. Those who are
repelled by the idea of man's derivation from a simian type should
remember that the theory implies rather more than this, namely, that man
is the outcome of a genealogy which has implied many millions of years
of experimenting and sifting--the groaning and travailing of a whole
creation. Speaking of man's mental qualities, Sir Ray Lankester says:
"They justify the view that man forms a new departure in the gradual
unfolding of Nature's predestined plan." In any case, we have to try to
square our views with the facts, not the facts with our views, and while
one of the facts is that man stands unique and apart, the other is that
man is a scion of a progressive simian stock. Naturalists have exposed
the pit whence man has been digged and the rock whence he has been hewn,
but it is surely a heartening encouragement to know that it is an
ascent, not a descent, that we have behind us. There is wisdom in
Pascal's maxim:

It is dangerous to show man too plainly how like he is to the
animals, without, at the same time, reminding him of his greatness.
It is equally unwise to impress him with his greatness and not with
his lowliness. It is worse to leave him in ignorance of both. But it
is very profitable to recognise the two facts.

Sec. 3

Man's Pedigree

The facts of anatomy, physiology, and embryology, of which we have given
illustrations, all point to man's affiliation with the order of monkeys
and apes. To this order is given the name Primates, and our first and
second question must be when and whence the Primates began. The rock
record answers the first question: the Primates emerged about the dawn
of the Eocene era, when grass was beginning to cover the earth with a
garment. Their ancestral home was in the north in both hemispheres, and
then they migrated to Africa, India, Malay, and South America. In North
America the Primates soon became extinct, and the same thing happened
later on in Europe. In this case, however, there was a repeopling from
the South (in the Lower Miocene) and then a second extinction (in the
Upper Pliocene) before man appeared. There is considerable evidence in
support of Professor R. S. Lull's conclusion, that in Southern Asia,
Africa, and South America the evolution of Primates was continuous since
the first great southward migration, and there is, of course, an
abundant modern representation of Primates in these regions to-day.

As to the second question: Whence the Primates sprang, the answer must
be more conjectural. But it is a reasonable view that Carnivores and
Primates sprang from a common Insectivore stock, the one order diverging
towards flesh-eating and hunting on the ground, the other order
diverging towards fruit-eating and arboreal habits. There is no doubt
that the Insectivores (including shrews, tree-shrews, hedgehog, mole,
and the like) were very plastic and progressive mammals.

What followed in the course of ages was the divergence of branch after
branch from the main Primate stem. First there diverged the South
American monkeys on a line of their own, and then the Old World monkeys,
such as the macaques and baboons. Ages passed and the main stems gave
off (in the Oligocene period) the branch now represented by the small
anthropoid apes--the gibbon and the siamang. Distinctly later there
diverged the branch of the large anthropoid apes--the gorilla, the
chimpanzee, and the orang. That left a generalised humanoid stock
separated off from all monkeys and apes, and including the immediate
precursors of man. When this sifting out of a generalised humanoid stock
took place remains very uncertain, some authorities referring it to the
Miocene, others to the early Pliocene. Some would estimate its date at
half a million years ago, others at two millions! The fact is that
questions of chronology do not as yet admit of scientific statement.

[Illustration: SIDE-VIEW OF SKULL OF MAN (M) AND GORILLA (G)

Notice in the gorilla's skull the protrusive face region, the big
eyebrow ridges, the much less domed cranial cavity, the massive lower
jaw, the big canine teeth. Notice in man's skull the well-developed
forehead, the domed and spacious cranial cavity, the absence of any
snout, the chin process, and many other marked differences separating
the human skull from the ape's.]

[Illustration: THE SKULL AND BRAIN-CASE OF PITHECANTHROPUS, THE JAVA
APE-MAN, AS RESTORED. BY J. H. McGREGOR FROM THE SCANTY REMAINS

The restoration shows the low, retreating forehead and the prominent
eyebrow ridges.]

[Illustration: SUGGESTED GENEALOGICAL TREE OF MAN AND ANTHROPOID APES

From Sir Arthur Keith; the lettering to the right has been slightly
simplified.]

We are on firmer, though still uncertain, ground when we state the
probability that it was in Asia that the precursors of man were
separated off from monkeys and apes, and began to be terrestrial rather
than arboreal. Professor Lull points out that Asia is nearest to the
oldest known human remains (in Java), and that Asia was the seat of the
most ancient civilisations and the original home of many domesticated
animals and cultivated plants. The probability is that the cradle of the
human race was in Asia.

Man's Arboreal Apprenticeship

At this point it will be useful to consider man's arboreal
apprenticeship and how he became a terrestrial journeyman. Professor
Wood Jones has worked out very convincingly the thesis that man had no
direct four-footed ancestry, but that the Primate stock to which he
belongs was from its first divergence arboreal. He maintains that the
leading peculiarities of the immediate precursors of man were wrought
out during a long arboreal apprenticeship. The first great gain of
arboreal life on bipedal erect lines (not after the quadrupedal fashion
of tree-sloths, for instance) was the emancipation of the hand. The
foot became the supporting and branch-gripping member, and the hand was
set free to reach upward, to hang on by, to seize the fruit, to lift it
and hold it to the mouth, and to hug the young one close to the breast.
The hand thus set free has remained plastic--a generalised, not a
specialised member. Much has followed from man's "handiness."

The arboreal life had many other consequences. It led to an increased
freedom of movement of the thigh on the hip joint, to muscular
arrangements for balancing the body on the leg, to making the backbone a
supple yet stable curved pillar, to a strongly developed collar-bone
which is only found well-formed when the fore-limb is used for more than
support, and to a power of "opposing" the thumb and the big toe to the
other digits of the hand and foot--an obvious advantage for
branch-gripping. But the evolution of a free hand made it possible to
dispense with protrusive lips and gripping teeth. Thus began the
recession of the snout region, the associated enlargement of the
brain-box, and the bringing of the eyes to the front. The overcrowding
of the teeth that followed the shortening of the snout was one of the
taxes on progress of which modern man is often reminded in his dental
troubles.

Another acquisition associated with arboreal life was a greatly
increased power of turning the head from side to side--a mobility very
important in locating sounds and in exploring with the eyes.
Furthermore, there came about a flattening of the chest and of the back,
and the movements of the midriff (or diaphragm) came to count for more
in respiration than the movements of the ribs. The sense of touch came
to be of more importance and the sense of smell of less; the part of the
brain receiving tidings from hand and eye and ear came to predominate
over the part for receiving olfactory messages. Finally, the need for
carrying the infant about among the branches must surely have implied an
intensification of family relations, and favoured the evolution of
gentleness.

[Illustration: _Photo: New York Zoological Park._

THE GIBBON IS LOWER THAN THE OTHER APES AS REGARDS ITS SKULL AND
DENTITION, BUT IT IS HIGHLY SPECIALIZED IN THE ADAPTATION OF ITS LIMBS
TO ARBOREAL LIFE]

[Illustration: _Photo: New York Zoological Park._

THE ORANG HAS A HIGH ROUNDED SKULL AND A LONG FACE]

[Illustration: _Photo: British Museum (Natural History)._

COMPARISONS OF THE SKELETONS OF HORSE AND MAN

Bone for bone, the two skeletons are like one another, though man is a
biped and the horse a quadruped. The backbone in man is mainly vertical;
the backbone in the horse is horizontal except in the neck and the tail.
Man's skull is mainly in a line with the backbone; the horse's at an
angle to it. Both man and horse have seven neck vertebrae. Man has five
digits on each limb; the horse has only one digit well developed on each
limb.]

It may be urged that we are attaching too much importance to the
arboreal apprenticeship, since many tree-loving animals remain to-day
very innocent creatures. To this reasonable objection there are two
answers, first that in its many acquisitions the arboreal evolution of
the _humanoid_ precursors of man prepared the way for the survival of a
_human_ type marked by a great step in brain-development; and second
that the passage from the humanoid to the human was probably associated
with _a return to mother earth_.

According to Professor Lull, to whose fine textbook, _Organic Evolution_
(1917), we are much indebted, "climatic conditions in Asia in the
Miocene or early Pliocene were such as to compel the descent of the
pre-human ancestor from the trees, a step which was absolutely essential
to further human development." Continental elevation and consequent
aridity led to a dwindling of the forests, and forced the ape-man to
come to earth. "And at the last arose the man."

According to Lull, the descent from the trees was associated with the
assumption of a more erect posture, with increased liberation and
plasticity of the hand, with becoming a hunter, with experiments towards
clothing and shelter, with an exploring habit, and with the beginning of
communal life.

It is a plausible view that the transition from the humanoid to the
human was effected by a discontinuous variation of considerable
magnitude, what is nowadays called a _mutation_, and that it had mainly
to do with the brain and the vocal organs. But given the gains of the
arboreal apprenticeship, the stimulus of an enforced descent to terra
firma, and an evolving brain and voice, we can recognise accessory
factors which helped success to succeed. Perhaps the absence of great
physical strength prompted reliance on wits; the prolongation of infancy
would help to educate the parents in gentleness; the strengthening of
the feeling of kinship would favour the evolution of family and social
life--of which there are many anticipations at lower levels. There is
much truth in the saying: "Man did not make society, society made man."

A continuation of the story will deal with the emergence of the
primitive types of man and the gradual ascent of the modern species.

Sec. 4

Tentative Men

So far the story has been that of the sifting out of a humanoid stock
and of the transition to human kind, from the ancestors of apes and men
to the man-ape, and from the man-ape to man. It looks as if the
sifting-out process had proceeded further, for there were several human
branches that did not lead on to the modern type of man.

1. The first of these is represented by the scanty fossil remains known
as _Pithecanthropus erectus_, found in Java in fossiliferous beds which
date from the end of the Pliocene or the beginning of the Pleistocene
era. Perhaps this means half a million years ago, and the remains
occurred along with those of some mammals which are now extinct.
Unfortunately the remains of Pithecanthropus the Erect consisted only of
a skull-cap, a thigh-bone, and two back teeth, so it is not surprising
that experts should differ considerably in their interpretation of what
was found. Some have regarded the remains as those of a large gibbon,
others as those of a pre-human ape-man, and others as those of a
primitive man off the main line of ascent. According to Sir Arthur
Keith, Pithecanthropus was "a being human in stature, human in gait,
human in all its parts, save its brain." The thigh-bone indicates a
height of about 5 feet 7 inches, one inch less than the average height
of the men of to-day. The skull-cap indicates a low, flat forehead,
beetling brows, and a capacity about two-thirds of the modern size. The
remains were found by Dubois, in 1894, in Trinil in Central Java.

2. The next offshoot is represented by the Heidelberg man (_Homo
heidelbergensis_), discovered near Heidelberg in 1907 by Dr.
Schoetensack. But the remains consisted only of a lower jaw and its
teeth. Along with this relic were bones of various mammals, including
some long since extinct in Europe, such as elephant, rhinoceros, bison,
and lion. The circumstances indicate an age of perhaps 300,000 years
ago. There were also very crude flint implements (or eoliths). But the
teeth are human teeth, and the jaw seems transitional between that of an
anthropoid ape and that of man. Thus there was no chin. According to
most authorities the lower jaw from the Heidelberg sand-pit must be
regarded as a relic of a primitive type off the main line of human
ascent.

[Illustration: A RECONSTRUCTION OF THE JAVA MAN

(_Pithecanthropus erectus._)]

3. It was in all probability in the Pliocene that there took origin the
Neanderthal species of man, _Homo neanderthalensis_, first known from
remains found in 1856 in the Neanderthal ravine near Duesseldorf.
According to some authorities Neanderthal man was living in Europe a
quarter of a million years ago. Other specimens were afterwards found
elsewhere, e.g. in Belgium ("the men of Spy"), in France, in Croatia,
and at Gibraltar, so that a good deal is known of Neanderthal man. He
was a loose-limbed fellow, short of stature and of slouching gait, but a
skilful artificer, fashioning beautifully worked flints with a
characteristic style. He used fire; he buried his dead reverently and
furnished them with an outfit for a long journey; and he had a big
brain. But he had great beetling, ape-like eyebrow ridges and massive
jaws, and he showed "simian characters swarming in the details of his
structure." In most of the points in which he differs from modern man he
approaches the anthropoid apes, and he must be regarded as a low type of
man off the main line. Huxley regarded the Neanderthal man as a low form
of the modern type, but expert opinion seems to agree rather with the
view maintained in 1864 by Professor William King of Galway, that the
Neanderthal man represents a distinct species off the main line of
ascent. He disappeared with apparent suddenness (like some aboriginal
races to-day) about the end of the Fourth Great Ice Age; but there is
evidence that before he ceased to be there had emerged a successor
rather than a descendant--the modern man.

4. Another offshoot from the main line is probably represented by the
Piltdown man, found in Sussex in 1912. The remains consisted of the
walls of the skull, which indicate a large brain, and a high forehead
without the beetling eyebrows of the Neanderthal man and
Pithecanthropus. The "find" included a tooth and part of a lower jaw,
but these perhaps belong to some ape, for they are very discrepant. The
Piltdown skull represents the most ancient human remains as yet found in
Britain, and Dr. Smith Woodward's establishment of a separate genus
Eoanthropus expresses his conviction that the Piltdown man was off the
line of the evolution of the modern type. If the tooth and piece of
lower jaw belong to the Piltdown skull, then there was a remarkable
combination of ape-like and human characters. As regards the brain,
_inferred_ from the skull-walls, Sir Arthur Keith says:

All the essential features of the brain of modern man are to be seen
in the brain cast. There are some which must be regarded as
primitive. There can be no doubt that it is built on exactly the
same lines as our modern brains. A few minor alterations would make
it in all respects a modern brain.... Although our knowledge of the
human brain is limited--there are large areas to which we can assign
no definite function--we may rest assured that a brain which was
shaped in a mould so similar to our own was one which responded to
the outside world as ours does. Piltdown man saw, heard, felt,
thought, and dreamt much as we do still.

And this was 150,000 years ago at a modern estimate, and some would say
half a million.

There is neither agreement nor certainty as to the antiquity of man,
except that the modern type was distinguishable from its collaterals
hundreds of thousands of years ago. The general impression left is very
grand. In remote antiquity the Primate stem diverged from the other
orders of mammals; it sent forth its tentative branches, and the result
was a tangle of monkeys; ages passed and the monkeys were left behind,
while the main stem, still probing its way, gave off the Anthropoid
apes, both small and large. But they too were left behind, and the main
line gave off other experiments--indications of which we know in Java,
at Heidelberg, in the Neanderthal, and at Piltdown. None of these lasted
or was made perfect. They represent _tentative_ men who had their day
and ceased to be, our predecessors rather than our ancestors. Still, the
main stem goes on evolving, and who will be bold enough to say what
fruit it has yet to bear!

[Illustration: _After a model by J. H. McGregor._

PROFILE VIEW OF THE HEAD OF PITHECANTHROPUS, THE JAVA APE-MAN--AN EARLY
OFFSHOOT FROM THE MAIN LINE OF MAN'S ASCENT

The animal remains found along with the skull-cap, thigh-bone, and two
teeth of Pithecanthropus seem to indicate the lowest Pleistocene period,
perhaps 500,000 years ago.]

[Illustration: _From the reconstruction by J. H. McGregor._

PILTDOWN SKULL. THE DARK PARTS ONLY ARE PRESERVED, NAMELY PORTIONS OF
THE CRANIAL WALLS AND THE NASAL BONES

Some authorities include a canine tooth and part of the lower jaw which
were found close by. The remains were found in 1912 in Thames gravels in
Sussex, and are usually regarded as vastly more ancient than those of
Neanderthal Man. It has been suggested that Piltdown Man lived 100,000
to 150,000 years ago, in the Third Interglacial period.]

[Illustration: _Reproduced by permission from Osborn's "Men of the Old
Stone Age."_

SAND-PIT AT MAUER, NEAR HEIDELBERG: DISCOVERY SITE OF THE JAW OF
HEIDELBERG MAN

_a-b._ "Newer loess," either of Third Interglacial or of Postglacial
times.
_b-c._ "Older loess" (sandy loess), of the close of Second Interglacial
times.
_c-f._ The "sands of Mauer."
_d-e._ An intermediate layer of clay.

The white cross (X) indicates the spot at the base of the "sands of
Mauer" at which the jaw of Heidelberg was discovered.]

Primitive Men

Ancient skeletons of men of the modern type have been found in many
places, e.g. Combe Capelle in Dordogne, Galley Hill in Kent, Cro-Magnon
in Perigord, Mentone on the Riviera; and they are often referred to as
"Cave-men" or "men of the Early Stone Age." They had large skulls, high
foreheads, well-marked chins, and other features such as modern man
possesses. They were true men at last--that is to say, like ourselves!
The spirited pictures they made on the walls of caves in France and
Spain show artistic sense and skill. Well-finished statuettes
representing nude female figures are also known. The elaborate burial
customs point to a belief in life after death. They made stone
implements--knives, scrapers, gravers, and the like, of the type known
as Palaeolithic, and these show interesting gradations of skill and
peculiarities of style. The "Cave-men" lived between the third and
fourth Ice Ages, along with cave-bear, cave-lion, cave-hyaena, mammoth,
woolly rhinoceros, Irish elk, and other mammals now extinct--taking us
back to 30,000-50,000 years ago, and many would say much more. Some of
the big-brained skulls of these Palaeolithic cave-men show not a single
feature that could be called primitive. They show teeth which in size
and form are exactly the same as those of a thousand generations
afterwards--and suffering from gumboil too! There seems little doubt
that these vigorous Palaeolithic Cave-men of Europe were living for a
while contemporaneously with the men of Neanderthal, and it is possible
that they directly or indirectly hastened the disappearance of their
more primitive collaterals. Curiously enough, however, they had not
themselves adequate lasting power in Europe, for they seem for the most
part to have dwindled away, leaving perhaps stray present-day survivors
in isolated districts. The probability is that after their decline
Europe was repeopled by immigrants from Asia. It cannot be said that
there is any inherent biological necessity for the decline of a vigorous
race--many animal races go back for millions of years--but in mankind
the historical fact is that a period of great racial vigour and success
is often followed by a period of decline, sometimes leading to practical
disappearance as a definite race. The causes of this waning remain very
obscure--sometimes environmental, sometimes constitutional, sometimes
competitive. Sometimes the introduction of a new parasite, like the
malaria organism, may have been to blame.

After the Ice Ages had passed, perhaps 25,000 years ago, the Palaeolithic
culture gave place to the Neolithic. The men who made rudely dressed but
often beautiful stone implements were succeeded or replaced by men who
made polished stone implements. The earliest inhabitants of Scotland
were of this Neolithic culture, migrating from the Continent when the
ice-fields of the Great Glaciation had disappeared. Their remains are
often associated with the "Fifty-foot Beach" which, though now high and
dry, was the seashore in early Neolithic days. Much is known about these
men of the polished stones. They were hunters, fowlers, and fishermen;
without domesticated animals or agriculture; short folk, two or three
inches below the present standard; living an active strenuous life.
Similarly, for the south, Sir Arthur Keith pictures for us a Neolithic
community at Coldrum in Kent, dating from about 4,000 years ago--a few
ticks of the geological clock. It consisted, in this case, of
agricultural pioneers, men with large heads and big brains, about two
inches shorter in stature than the modern British average (5 ft. 8 in.),
with better teeth and broader palates than men have in these days of
soft food, with beliefs concerning life and death similar to those that
swayed their contemporaries in Western and Southern Europe. Very
interesting is the manipulative skill they showed on a large scale in
erecting standing stones (probably connected with calendar-keeping and
with worship), and on a small scale in making daring operations on the
skull. Four thousand years ago is given as a probable date for that
early community in Kent, but evidences of Neolithic man occur in
situations which demand a much greater antiquity--perhaps 30,000 years.
And man was not young then!

[Illustration: PAINTINGS ON THE ROOF OF THE ALTAMIRA CAVE IN NORTHERN
SPAIN, SHOWING A BISON ABOVE AND A GALLOPING BOAR BELOW

The artistic drawings, over 2 feet in length, were made by the Reindeer
Men or "Cromagnards" in the time of the Upper or Post-Glacial
Pleistocene, before the appearance of the Neolithic men.]

We must open one more chapter in the thrilling story of the Ascent of
Man--the Metal Ages, which are in a sense still continuing. Metals began
to be used in the late Polished Stone (Neolithic) times, for there were
always overlappings. Copper came first, Bronze second, and Iron last.
The working of copper in the East has been traced back to the fourth
millennium B.C., and there was also a very ancient Copper Age in the New
World. It need hardly be said that where copper is scarce, as in
Britain, we cannot expect to find much trace of a Copper Age.

The ores of different metals seem to have been smelted together in an
experimental way by many prehistoric metallurgists, and bronze was the
alloy that rewarded the combination of tin with copper. There is
evidence of a more or less definite Bronze Age in Egypt and Babylonia,
Greece and Europe.

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