228 SOCIAL HEREDITY AND SOCIAL EVOLUTION 



of the savage races has been one of ceaseless migra- 

 tion from place to place, driven by this eternal force 

 of starvation. Lack of food has limited the size of 

 the families. The impossibility of carrying a large 

 family of children on these migrations, together with 

 the knowledge that the scarcity of food will produce 

 suffering if the family grows too large, lies at the 

 foundation of the destruction of so many helpless 

 babes. Infanticide is to them a means of self -protec- 

 tion. 



With the development of agricultural habits, how- 

 ever, man placed himself at once in a different atti- 

 tude toward this problem of his struggle with nature. 

 Agriculture has taught him to make his own environ- 

 ment. He has reversed the condition of life found 

 among animals and savages. Instead of endeavoring 

 to adapt himself to the conditions of the world 

 around him, man now tries to adapt the world to his 

 own necessities. This complete change in attitude 

 has made possible both civilization and society. 

 From the very beginning social progress has been 

 characterized by a struggle with nature, and by a 

 successful attempt on the part of man to change the 

 conditions of inanimate nature in such a way as to 

 make his own life larger and easier. Agriculture has 

 enlarged the world very rapidly. A piece of land 

 large enough to support a single hunter living upon 

 fruits and captured animals will support a thousand 

 agriculturists, and agriculture has thus increased the 

 size of the world at least a thousand times. This 

 change enables man to live in the same place genera- 

 tion after generation, with the confidence that the 

 land in his possession will continue to bring forth 

 more than a sufficiency of food. 



