22 THE LAW OF BIRTHS AND DEATHS 



used with regularity by the vast majority of married 

 couples of child-bearing age from week to week, and this 

 would be true of all the other leading countries of the 

 world. This would necessitate a trade comparable in 

 magnitude with that in some of the commoner necessaries 

 of life, such as mustard or salt. No evidence has ever 

 been produced of the existence of a trade of such magni- 

 tude. The fact that many shops are devoted to their 

 sale in London or Paris proves little. Over the greater 

 part of the country they can seldom be seen exposed 

 for sale at all. The onus of proof rests with those who 

 assert the existence of such a trade, but though com- 

 missions have sat in France, Australia and London, they 

 have never yet obtained evidence of the existence of a 

 trade comparable in magnitude with the effects it is 

 supposed to have produced. 



These commissions, indeed, failed to concentrate on 

 the really essential question. They should have investi- 

 gated the subject by asking if there has, or has not, been 

 a vast decline in the birthrate due to natural causes, 

 and which could not be due to the use of contraceptives 

 on no matter how vast a scale. But their examination 

 of this aspect of the problem was perfunctory in the 

 extreme. To prove that prevention is practised on a 

 considerable scale is not to prove that there has been 

 no decline in the birthrate due to natural causes ; and if 

 there has been such a decline, it is clear that we cannot 

 solve the problem of the birthrate until we have ascer- 

 tained its extent, character and cause. And by asking 

 ourselves this question we go straight to the essential 

 point and avoid an immense amount of tedious and un- 

 profitable discussion. It is possible to answer it by the 

 use of test cases. 



We will first take the results of three inquiries carried 



