INTRODUCTION 3 



differences of innate qualities, of mental and physical 

 characters. Already, to some extent, the qualities 

 embedded in the different classes are beginning to be 

 understood, and can be subjected to statistical analysis. 

 Already we see that, by legislation or by the pressure of 

 enlightened public opinion, it may become possible here 

 and there to direct or restrain the growth of population, 

 and thus modify the future history of the race. If, by 

 increased medical and hygienic knowledge, the feeble- 

 minded and weak-bodied stocks be allowed to survive, 

 and if, as seems to be the case at present, they repro- 

 duce themselves faster than do the better stocks, the 

 relative numbers of such persons in the country must 

 increase, and the average quality of the race deteriorate. 

 If, by economic and social conditions, children be made 

 too heavy a burden on the more desirable elements of 

 the population, there is danger that the thrifty and 

 far-seeing members of the community will postpone 

 marriage, and, when married, restrict the number of 

 their offspring. Thus, while the weak and careless 

 elements grow at an increasing rate, the good stocks of 

 the people check their rate of growth or even diminish 

 in number, and the selective deterioration of the race 

 is hastened in two ways. 



How far are such tendencies apparent or immanent ? 

 How can we guard against them or minimize their 

 effects ? How can we maintain or improve the innate 

 qualities of our race without trenching on moral freedom 

 and personal responsibility, on ethical standards and 

 religious convictions .? 



It has been thought by some men that our growing 



