296 Heredity and Environment 



race is to be regenerated through sterilization. But unfortunately 

 this reform begins at home among those who because of good 

 hereditary traits should not be infertile. Sterility is too easily 

 acquired; what is not so easily brought about is the fertility of 

 the better lines. Galton was far wiser than most of his follow- 

 ers for he realized the necessity of increasing the families of the 

 better types as well as of decreasing those of the worse. 



What Bernard Shaw regards as the greatest discovery of the 

 nineteenth century, viz., the means of artificially limiting the size 

 of families, may prove to be the greatest menace to the human 

 race. If it were applied only to those who should not have chil- 

 dren or to those who should for various reasons have only a few 

 children it would be a blessing to mankind. But applied to those 

 who could and should have many children it is no gift of the gods. 

 No one denies that the chief motive for limiting the size of fam- 

 ilies is personal comfort and pleasure 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 en- 

 vironment is more important that heredity, which is contrary to 

 all the biological 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 

 conveniently 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 individuals 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 variety of potential person- 

 alities in human germ cells but only an infinitesimal number ever 

 come to development. If this number is still further reduced 

 by artificial means the race will be made the poorer not merely 



