RETROSPECT AND PROSPECT 381 



at least, we may well ask with E. Carpenter, "Is Civilization a 

 disease? " If it is a disease it is one which has apparently proven 

 fatal to many nations in the past. Without venturing to discuss 

 the various explanations of the downfall of civilizations it may be 

 said that, so far as insight can be obtained in the racial changes 

 that have accompanied this process of decay, the ethnic stocks 

 which were responsible for the cultural advancement that oc- 

 curred became gradually bred out and replaced by the blood of 

 alien peoples. Decadence from within was often the prelude to 

 conquest from without, but whether the old stock was replaced by 

 conquering invaders, peaceful immigrants, or the progeny of 

 slaves, the result was in many respects the same. 



In the present book we have made what is perhaps a very 

 inadequate effort to diagnose some of the racial maladies that 

 affect our own day and generation. It is only by recognizing these 

 and understanding the methods of their working that effective 

 means can be taken to keep them in check. Rather feeble at- 

 tempts have been made to curtail the propagation of mental 

 defectives, through sterilizing or segregating some of the worst of 

 these undesirable elements. This practice carried on much more 

 extensively than it has been would undoubtedly relieve society 

 of an immense burden. But the elimination of our worst defec- 

 tives would not meet the most serious difficulty which consists in 

 the loss of those stocks which carry our best inheritance. It is 

 doubtful if the pecuniary rewards which have sometimes been 

 advocated for increasing the birth rate of desirable parents 

 would prove very effective. There is much to be said in favor of 

 making parenthood voluntary in all classes so as to restrict the 

 birth rate among the people who occupy the rather broad belt 

 between the obviously defective and ordinary mediocrity. This 

 of itself would lead to a greater relative fecundity among those of 

 superior inheritance, and so long as restriction is not carried far 

 enough to prevent all increase of the population, the result would 

 doubtless be eugenically and socially desirable. Through reduc- 

 ing the death rate the natural increase of several countries has 

 become more rapid, despite the diminishing numbers of births. 



