THE CAUSES OF THE DECLINING BIRTH RATE 165 



has not been allowed to do so. We cannot, therefore, for several 

 reasons attribute to reduced infant mortality a large part of the 

 decline of the birth rate, although this has doubtless been one 

 factor. 



The influence of venereal diseases upon the decline of the 

 birth rate, although undoubtedly considerable, is difficult to 

 estimate. No reliable data exists as to the proportion of the 

 population affected by these diseases, although their prevalence 

 is a matter of common knowledge. 1 That the two most common 

 venereal maladies are potent causes of sterility has long been 

 recognized. Gonorrhoea, which, according to several medical 

 authorities, has at one time or another affected more than 50 per 

 cent of the adult male population, is responsible for a large 

 amount of sterility, the extent of which the medical profession has 

 only recently come to appreciate. Through obstructing the vas 

 deferens or epididymis, as well as in other ways, gonorrhoea is a 

 not infrequent cause of sterility in the male sex. Furbringer 

 attributes one-third of all sterile marriages to this cause. Kohern 

 found in 96 sterile marriages 30 per cent due to the absence of 

 sperms in the seminal fluid of the husband. The greatest damage 

 is done, however, by the transfer of the infection to wives, which 

 often takes place even after the disease has apparently ceased in 

 the husband. Gonococcus infection, according to the moderate 

 estimate of Prinzing, causes 13 per cent of sterile marriages. 

 Noggerath places the percentage of sterility in woman due to this 

 cause as high as 50, and Neisser believes that 45 per cent of sterile 

 marriages are due to gonorrhoea of one or the other sex. This dis- 

 ease is a frequent cause of failure to produce more children after 

 the birth of the first child owing to the rapid extension of the in- 

 fection after childbirth. The extent to which complete or partial 

 sterility is due directly or indirectly to this cause must be very 

 considerable, although it is not capable of precise measurement. 



1 The best index of the prevalence of venereal diseases in the U. S. is afforded 

 by the examination of recruits hi the late war. According to the Report of the 

 Surgeon General for 1919, 5.6 per cent were found to be infected at the time of the 

 draft. This figure includes negroes among whom venereal infections were about 

 seven times as frequent as among th whites. 



