30 THE LAW OF BIRTHS AND DEATHS 



Society, I found that the average size of their families 

 was 2 '33, and that 25 per cent, of the marriages were 

 childless. The Eugenics Society is composed of able 

 people who believe that it is desirable to secure the 

 largest possible proportion of children from the ablest 

 sections of the community, and that the present position 

 in which the least capable are reproducing most rapidly 

 is likely to be disastrous to the efficiency of the race in 

 the long run. It is not at all likely that they would 

 publicly expound such beliefs and yet take measures to 

 limit their own families, seeing that they are themselves 

 among the abler sections of the community. Here again 

 the number of completely sterile marriages provides the 

 best test, and by far the most probable explanation is 

 that the vast proportion of such marriages among them 

 is due to the same causes which have produced a similar 

 result among the staff of Cambridge University. The 

 proportion is greater than among the nobility, and illus- 

 trates the fact that intellectual activity seems to be more 

 potent in reducing fertility than social position. It may 

 be added that the families do not consist almost exclu- 

 sively of one or two children as we should expect on the 

 contraceptive theory, but of sterile marriages, with ones, 

 twos, threes, fours and fives, scattered in just the random 

 fashion we should expect from a natural law. 



A still more instructive case is that of the members 

 of the National Birthrate Commission. Here is a body 

 of people who sincerely believe that unless some means 

 are found of grappling successfully with the birthrate 

 problem we run the gravest risk of ultimate disaster. 

 So strongly do they feel on this point that they give 

 their services gratis for a considerable time in order to 

 investigate the problem. Yet I find that the average 

 number of children per family among them is only T76, 



