INTRODUCTION xix 



sponsive organism performing an enormous 

 variety of complicated and intricate acts some 

 of which are indicative of the highest order 

 of intelligence; and, secondly, he possesses 

 powers of reproduction in that he can leave 

 behind him offspring who, while they carry 

 with them the vast inheritance of the race, 

 are also the means of that gradual change 

 which has made his own coming possible. In 

 deaHng with the natural history of man in 

 the following lectures these two aspects of his 

 nature will be the chief topics for consider' 

 ation. 



