362 HEREDITY AND ENVIRONMENT 



the present age, as it is in lower organisms. 

 For man and for every other living creature 

 heredity fixes the possibilities of development, 

 it "sets bounds about us which we cannot 

 pass"; but the more complex those possibilities 

 become the more complex must be the environ- 

 ment which calls them forth and the more 

 varied become the results of development un- 

 der altered conditions of life. 



Functional activity also plays a larger part 

 in man's development than in that of any other 

 animal, owing to the longer period of his 

 development and to the more extensive and 

 varied training which he is capable of under- 

 going. It is a notable fact that the period of 

 immaturity in man is longer than in any other 

 animal, and it is during this formative period 

 that environment and education have their 

 greatest influence. Other animals develop 

 much more rapidly than man but that develop- 

 ment sooner comes to an end. The children of 

 lower races of man develop more rapidly than 

 those of higher races but in such cases they 

 also cease to develop at an earlier age. The 

 prolongation of the period of infancy and of 



