seem to me to take us appreciably nearer to that lower
pithecoid form, by the modification of which he has, probably, become
what he is." The Californian remains and works of art, above referred
to, give no indication of a specially low form of man; and it remains an
unsolved problem why no traces of the long line of man's ancestors, back
to the remote period when he first branched off from the pithecoid type,
have yet been discovered.

It has been objected by some writers--notably by Professor Boyd
Dawkins--that man did not probably exist in Pliocene times, because
almost all the known mammalia of that epoch are distinct species from
those now living on the earth, and that the same changes of the
environment which led to the modification of other mammalian species
would also have led to a change in man. But this argument overlooks the
fact that man differs essentially from all other mammals in this
respect, that whereas any important adaptation to new conditions can be
effected in them only by a change in bodily structure, man is able to
adapt himself to much greater changes of conditions by a mental
development leading him to the use of fire, of tools, of clothing, of
improved dwellings, of nets and snares, and of agriculture. By the help
of these, without any change whatever in his bodily structure, he has
been able to spread over and occupy the whole earth; to dwell securely
in forest, plain, or mountain; to inhabit alike the burning desert or
the arctic wastes; to cope with every kind of wild beast, and to provide
himself with food in districts where, as an animal trusting to nature's
unaided productions, he would have starved.[225]

It follows, therefore, that from the time when the ancestral man first
walked erect, with hands freed from any active part in locomotion, and
when his brain-power became sufficient to cause him to use his hands in
making weapons and tools, houses and clothing, to use fire for cooking,
and to plant seeds or roots to supply himself with stores of food, the
power of natural selection would cease to act in producing modifications
of his body, but would continuously advance his mind through the
development of its organ, the brain. Hence man may have become truly
man--the species, Homo sapiens--even in the Miocene period; and while
all other mammals were becoming modified from age to age under the
influence of ever-changing physical and biological conditions, he would
be advancing mainly in