520 LAWS OF MULTIPLICATION. 



to be facts belonging to a different category from that in 

 which they are placed, and harmonize with the rest when 

 rightly interpreted. 



The conformity of human fertility to the laws of multipli- 

 cation in general, being granted, it remains to inquire what 

 effects must be caused by permanent changes in men's natures 

 and circumstances. Thus far we have observed how, by their 

 exceptionally-high evolution and exceptionally-low fertility, 

 mankind display the inverse variation between Individuation 

 and Genesis, in one of its extremes. And we have also ob- 

 served how mankind, like other kinds, are functionally changed 

 in their rates of multiplication by changes of conditions. But 

 we have not observed how alteration of structure in Man 

 entails alteration of fertility. The influence of this factor is 

 so entangled with the influences of other factors which are 

 for the present more potent, that we cannot recognize it. 

 Here, if we proceed at all, we must proceed deductively. 



[NOTE. From among the publications of the American 

 Academy of Political and Social Science, there was sent to 

 me some years ago an essay entitled " The Significance of a 

 Decreasing Birth Kate" by (Miss) J. L. Brownell, Fellow in 

 Political Science, Bryn Mawr College. This essay contains 

 a number of elaborate comparisons drawn from the vital 

 statistics of the tenth United States Census. The results 

 of these comparisons are thus summed up : 



" 1. Whether or not it be true that the means spoken of by Dr. 

 Billings, M. Dumont, M. Levasseur, and Dr. Edson has become nn 

 important factor in the diminishing birth-rate of civilized countries, 

 it is evident that it is not the only factor, and that, quite apart from 

 voluntary prevention, there is a distinct problem to be investigated. 

 This is shown by the fact that the white and the colored birth-rate 

 vary together. 



" 2. Mr. Spencer's generalization that the birth-rate diminishes ns 

 the rate of individual evolution increases is confirmed by a comparison 

 of the birth-rates with the death-rates from nervous diseases, and also 



