PREFACE 



. 



THIS little work, as its title suggests, is an attempt to 

 place the problems of animal fertility and the birthrate 

 on a more scientific footing than they have hitherto 

 held. It endeavours to show that the decline of the 

 birthrate cannot be explained on the hypothesis that it 

 is due to the deliberate evasion of child-bearing ; but 

 that it can be explained as the result of a natural law 

 the function of which is to adjust the degree of fertility 

 to suit approximately the needs of the race. 



The accepted theory cannot, by any stretch of in- 

 genuity, be made to account for many of the most 

 significant features of the birthrate problem. It cannot 

 account for the vast and increasing proportion of com- 

 pletely sterile marriages among the intellectual classes 

 in all countries, among the British nobility, and among 

 the wealthy classes generally unless, indeed, its advo- 

 cates are prepared to make, without a particle of reliable 

 evidence in its support, the remarkable assumption that 

 anything up to 25 per cent, of these classes take the 

 most elaborate and troublesome precautions, from the 

 very marriage eve, to avoid having a single child. It 

 cannot account for rises in the birthrate such as took 

 place during the early part of last century in England 

 and recently in Japan. It cannot account for the seasonal 

 fluctuations of the birthrate. It ignores the fact that 

 the use of contraceptives involves the most elaborate 

 and troublesome precautions at a time when the parties 



5 



4CG633 



