250 
THE DESCENT OF MAN. 
Part I. 
acted so powerfully on innumerable animals, both high 
and low in the scale. It can further be shewn that the 
differences between the races of man, as in colour, hairy- 
ness, form of features, &c., are of the nature which it 
might have been expected would have been acted on by 
sexual selection. But in order to treat this subject in a 
fitting manner, I have found it necessary to pass the 
whole animal kingdom in review ; I have therefore de- 
voted to it the Second Part of this work. At the close 
I shall return to man, and, after attempting to shew 
how far he has been modified through sexual selection, 
will give a brief summary of the chapters in this First 
Part. 
