656 



population in general ; I will now proceed to another result of my 

 investigation, which was as surprising as it was unexpected. 



It had attracted my notice, while working out my material, that 

 tiie older people mentioned therein were often characterized by a 

 late appearance of the nienarche. This observation gave rise to the 

 question whether the nienarche could have undergone some change 

 during the last decades, in such a manner that sexual maturity in 

 the youngest generation begins, on an average, at an earlier age 

 tiian in the former generations. 1 liave tried to tind an answer to 

 this question in two ways. In the first place 1 collected from my 

 material data referring to persons born l)efore 1880, and calculated 

 from these the average age of the menarche. Secondly I tried to obtain 

 data relating to the menarche in mother and daughters. Especially 

 this last is difficult, considering the fact that only a very few of 

 the women can actually mention tiie year of the menarche, much less 

 the mouth. Yet I have succeeded in collecting a number of such data. 



Both ways led to the same result, viz. that the menarche in what 

 we may call the youngest generation, as regards sexual maturity, 

 arrives at a considerably earlier period than formerly. I will return 

 to the cause and significance of this phenomenon after communicating 

 the pure facts. 



Let us begin with the menarche in women born before 1880. 

 In my material concerning them there were 98 data of tiie menar- 

 che according to year and month, and furthermore I possessed 104 

 cases in which only the age was mentioned. These 232 cases have 

 been systematically arranged in Table IV, and curve B in tig. I 

 gives the direction in percentages for each age. 



If one compares Table IV witii Table I, the following will be 

 seen : the beginning of the variability-curve lies, for women of the 



TABLE IV. 



