438 HEREDITY AND ENVIRONMENT 



one denies that the chief motive for limiting the 

 size of families is personal comfort and pleas- 

 ure rather than the welfare of the race. The 

 argument that people should have no more chil- 

 dren than they can rear in comfort or luxury 

 assumes that environment is more important 

 than heredity, which is contrary to all the bio- 

 logical evidence. In the breeding of horses or 

 cattle or men heredity is more potent than 

 environment ; and it is more important for the 

 welfare of the race that children with good in- 

 heritance should be brought into the world 

 than that parents should live easy lives and 

 have no more children than they can conven- 

 iently rear amid all the comforts of a luxury- 

 loving age. 



The method of evolution in the past has been 

 the production of enormous numbers of indi- 

 viduals and the elimination of the least fit. The 

 modern method of improving domestic races is 

 to select for reproduction the best types from 

 large numbers of individuals. One reason why 

 human evolution has gone on so slowly is to be 

 found in the slow breeding of men. Nature 

 has provided an almost infinite wealth and 



