VIII 
THE DEVELOPMENT OF HUMAN RACES UNDER THE LAW OF 
NATURAL SELECTION 1 
Among the most advanced students of man there exists a 
wide difference of opinion on some of the most vital questions 
respecting his nature and origin. Anthropologists are now, 
indeed, pretty well agreed that man is not a recent introduc- 
tion into the earth. All who have studied the question now 
admit that his antiquity is very great ; and that, though 
we have to some extent ascertained the minimum of time 
during which he must have existed, we have made no approxi- 
mation towards determining that far greater period during which 
he may have, and probably has existed. We can with toler- 
able certainty affirm that man must have inhabited the earth a 
thousand centuries ago, but we cannot assert that he positively 
did not exist, or that there is any good evidence against his 
having existed, for a period of ten thousand centuries. We 
know positively that he was contemporaneous with many now 
extinct animals, and has survived changes of the earth’s 
surface fifty or a hundred times greater than any that have 
occurred during the historical period; but we cannot place 
any definite limit to the number of species he may have 
outlived, or to the amount of terrestrial change he may 
have witnessed. 
Wide differences of opinion as to Man’s Origin 
But while on this question of man’s antiquity there is a 
very general agreement, — and all are waiting eagerly for 
1 First published in the Anthropological Review, May 1864 ; reprinted in 
Contributions, etc., with some alterations and additions. 
