MANIFESTED IN HUMAN SOCIETY 121 



educated and wealthy classes, and the facts through- 

 out show that the development of the nervous system 

 and nervous energy are accompanied by lessened 

 fertility. 



There is some reason to believe that the development 

 of the nervous system as the result of the increasingly 

 complex environment and increasing intellectual activity 

 is being accentuated from generation to generation. 

 " The parturitions of savage women resemble those of 

 the lower animals in their comparative ease, the mother 

 often resuming her duties immediately after birth. As 

 a rule, the difficulties of civilised women are very much 

 greater, for few of them are able to pursue their occupa- 

 tion for a fortnight or more after parturition. Their 

 difficulties increase with each successive generation. 

 At the beginning of the nineteenth century, according 

 to the statistics of the Rotunda Hospital, instrumental 

 aid was given to women on the average once in 608 cases. 

 Probably it is now given twenty times as often. No 

 doubt much of this change is due to the greater skill and 

 confidence acquired by medical men : but certainly not 

 all of it. Every medical man in ordinary practice sees 

 many cases in which the woman would perish but for 

 his aid. 



" Several attempts have been made to explain this 

 growing disproportion between the child's head and 

 the maternal pelvis." 1 It seems a fair inference that 

 the trouble is due to the increase in the relative size of 

 the child's head, and that this is due to the development 

 of the brain in response to the increasing complexity of 

 the environment. It is certainly not due to a decrease 

 in the width of the female pelvis among civilised races, 

 for the pelvis of the average civilised woman is conspicu- 

 1 Principles of Heredity, Dr. Archdall Reid, chap. xxv. 



