intelligence, but perhaps also in stature, and by
that advance alone would be able to maintain himself as the master of
all other animals and as the most widespread occupier of the earth. It
is quite in accordance with this view that we find the most pronounced
distinction between man and the anthropoid apes in the size and
complexity of his brain. Thus, Professor Huxley tells us that "it may be
doubted whether a healthy human adult brain ever weighed less than 31
or 32 ounces, or that the heaviest gorilla brain has exceeded 20
ounces," although "a full-grown gorilla is probably pretty nearly twice
as heavy as a Bosjes man, or as many an European woman."[226] The
average human brain, however, weighs 48 or 49 ounces, and if we take the
average ape brain at only 2 ounces less than the very largest gorilla's
brain, or 18 ounces, we shall see better the enormous increase which has
taken place in the brain of man since the time when he branched off from
the apes; and this increase will be still greater if we consider that
the brains of apes, like those of all other mammals, have also increased
from earlier to later geological times.

If these various considerations are taken into account, we must conclude
that the essential features of man's structure as compared with that of
apes--his erect posture and free hands--were acquired at a comparatively
early period, and were, in fact, the characteristics which gave him his
superiority over other mammals, and started him on the line of
development which has led to his conquest of the world. But during this
long and steady development of brain and intellect, mankind must have
continuously increased in numbers and in the area which they
occupied--they must have formed what Darwin terms a "dominant race." For
had they been few in numbers and confined to a limited area, they could
hardly have successfully struggled against the numerous fierce carnivora
of that period, and against those adverse influences which led to the
extinction of so many more powerful animals. A large population spread
over an extensive area is also needed to supply an adequate number of
brain variations for man's progressive improvement. But this large
population and long-continued development in a single line of advance
renders it the more difficult to account for the complete absence of
human or pre-human remains in all those deposits which have furnished,
in such rich abundance, the remains of other land anim