458 
DARWINISM 
CHAP. 
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.” 1 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 oft' 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 develop¬ 
ment which has led to his conquest of the world. But during 
this long and steady development of brain and intellect, man¬ 
kind 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 varia¬ 
tions 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 animals. It is true 
that the remains of apes are also very rare, and we may 
well suppose that the superior intelligence of man led him to 
avoid that extensive destruction by flood or in morass which 
seems to have often overwhelmed other animals. Yet, when 
1 Man's Place in Nature, p. 102. 
