Real men arose, we believe, by variational uplifts of considerable
magnitude which led to big and complex brains and to the power of
reasoned discourse. In some other lines of mammalian evolution there
were from time to time great advances in the size and complexity of the
brain, as is clear, for instance, in the case of horses and elephants.
The same is true of birds as compared with reptiles, and everyone
recognises the high level of excellence that has been attained by their
vocal powers. How these great cerebral advances came about we do not
know, but it has been one of the main trends of animal evolution to
improve the nervous system. Two suggestions may be made. First, the
prolongation of the period of ante-natal life, in intimate physiological
partnership with the mother, may have made it practicable to start the
higher mammal with a much better brain than in the lower orders, like
Insectivores and Rodents, and still more Marsupials, where the period
before birth (gestation) is short. Second, we know that the individual
development of the brain is profoundly influenced by the internal
secretions of certain ductless glands notably the thyroid. When this
organ is not functioning properly the child's brain development is
arrested. It may be that increased production of certain
hormones--itself, of course, to be accounted for--may have stimulated
brain development in man's remote ancestors.
Given variability along the line of better brains and given a process of
discriminate sifting which would consistently offer rewards to alertness
and foresight, to kin-sympathy and parental care, there seems no great
difficulty in imagining how Man would evolve. We must not think of an
Aristotle or a Newton except as fine results which justify all the
groaning and travailing; we must think of average men, of primitive
peoples to-day, and of our forbears long ago. We must remember how much
of man's advance is dependent on the external registration of the social
heritage, not on the slowly changing natural inheritance.
Looking backwards it is impossible, we think, to fail to recognise
progress. There is a ring of truth in the fine description Æschylus gave
of primitive men that--
first, beholding they beheld in vain, and, hearing, heard not, but,
like shapes in dreams, mixed all things wildly down the tedious
time, nor knew to build a house against the sun with wicketed sides,
nor any woodwork knew, but lived like silly ants, beneath the
ground, in hollow caves unsunned. There came to them no steadfast
sign of winter, nor of spring flower-perfumed, nor of summer full of
fruit, but blindly and lawlessly they did all things.
Contrast this picture with the position of man to-day. He has mastered
the forces of Nature and is learning to use their resources more and
more economically; he has harnessed electricity to his chariot and he
has made the ether carry his messages. He tapped supplies of material
which seemed for centuries unavailable, having learned, for instance,
how to capture and utilise the free nitrogen of the air. With his
telegraph and "wireless" he has annihilated distance, and he has added
to his navigable kingdom the depths of the sea and the heights of the
air. He has conquered one disease after another, and the young science
of heredity is showing him how to control in his domesticated animals
and cultivated plants the nature of the generations yet unborn. With all
his faults he has his ethical face set in the right direction. The main
line of movement is towards the fuller embodiment of the true, the
beautiful, and the good in healthy lives which are increasingly a
satisfaction in themselves.
[Illustration: _Photo: British Museum (Natural History)._
SIDE-VIEW OF A PREHISTORIC HUMAN SKULL DISCOVERED IN 1921 IN BROKEN HILL
CAVE, NORTHERN RHODESIA
Very striking are the prominent eyebrow ridges and the broad massive
face. The skull looks less domed than that of modern man, but its
cranial capacity is far above the lowest human limit. The teeth are
interesting in showing marked rotting or "caries," hitherto unknown in
prehistoric skulls. In all probability the Rhodesian man was an African
representative of the extinct Neanderthal species hitherto known only
from Europe.]
[Illustration: _After the restoration modelled by J. H. McGregor._
A CROMAGNON MAN OR CROMAGNARD, REPRESENTATIVE OF A STRONG ARTISTIC RACE
LIVING IN THE SOUTH OF FRANCE IN THE UPPER PLEISTOCENE, PERHAPS 25,000
YEARS AGO
They seemed to have lived for a while contemporaneously with the
Neanderthal Men, and there may have been interbreeding. Some Cromagnards
probably survive, but the race as a whole declined, and there was
repopulation of Europe from the East.]
[Illustration: _Reproduced by permission from Osborn's "Men of the Old
Stone Age."_
PHOTOGRAPH SHOWING A NARROW PASSAGE IN THE CAVERN OF FONT-DE-GAUME ON
THE BEUNE
Throughout the cavern the walls are crowded with engravings; on the left
wall, shown in the photograph, are two painted bison. In the great
gallery there may be found not less than eighty figures--bison,
reindeer, and mammoths. A specimen of the last is reproduced below.]
[Illustration: A MAMMOTH DRAWN ON THE WALL OF THE FONT-DE-GAUME CAVERN
The mammoth age was in the Middle Pleistocene, while Neanderthal Men
still flourished, probably far over 30,000 years ago.]
[Illustration: A GRAZING BISON, DELICATELY AND CAREFULLY DRAWN, ENGRAVED
ON A WALL OF THE ALTAMIRA CAVE, NORTHERN SPAIN
This was the work of a Reindeer Man or Cromagnard, in the Upper or
Post-Glacial Pleistocene, perhaps 25,000 years ago. Firelight must have
been used in making these cave drawings and engravings.]