THE TREND OF EVOLUTION 169 



or have children. Among these are some of the best human 

 stock the world possesses, and thus the race is made poorer 

 for many generations to come. Enforced celibacy in many 

 religious orders and societies of scholars has led to the ex- 

 tinction of some of the world's most gifted lines. The present 

 customs of mate selection condemn many of the finest women 

 in the world to spinsterhood, while the feather-brained and 

 sexually-daring "flappers" readily find mates. On the other 

 hand, personal ambition and selfishness, the prevalence of 

 prostitution and illicit sexual relations, the fear of misalliances, 

 divorce, and alimony are potent causes of bachelorhood. In 

 both cases the results are that many of the best human lines 

 are wiped out. Galton has shown that on the average people 

 who marry at twenty-two will leave twice as many descendants 

 at the end of a century as those who marry at thirty-three and 

 in a few generations they will actually possess the earth. And 

 yet the increasing time required for education, as well as more 

 luxurious standards of living, have made early marriages 

 almost impossible among professional and business classes, 

 with whom the most vigorous and fertile years of the repro- 

 ductive period are years of sterility. Finally, luxury, soft 

 living, and selfishness have made children unwelcome among 

 many married people who have shown qualities of success in 

 life and whose hereditary traits are above the average. Under 

 such conditions the general average of intelligence and social 

 fitness in the race as a whole must inevitably decline. 



There is an evident tendency to assortative mating in 

 modern society due not merely to similarity of social status 

 and ideals but also to the more potent factor of propinquity. 

 Generally men and women representing the extremes of the 

 social or intellectual scale do not marry and it has been claimed 

 that owing to this fact there is a constant tendency for society 

 to be split up into hereditary classes. Some authors maintain 

 that the more intelligent and the less intelligent elements of 



