238 POPULAR SCIENCE MONTHLY. 



Darwin turned his attention towards this point and accumulated 

 data. In the 'Descent of Man' he brought together many of the 

 chief facts then known concerning variation in man and woman. 

 All the evidence that he could find pointed in the same direction, 

 and he concluded (Part II., Ch. 8) that there is a 'greater general 

 variability in the male sex.' 



Some twenty years later in a summary study of human secondary 

 sexual characters entitled 'Man and Woman,' written as a brief 

 introduction to a more elaborate study of the sexual instinct in man, 

 I devoted a chapter to this question, dealing with it more compre- 

 hensively than had previously been done and drawing data from a 

 much wider field, but finding no reason to differ fundamentally from 

 the conclusions of Hunter, Burdach and Darwin. I could not indeed 

 assert that as regards man the greater variability of the male is 

 'general,' but all the facts available since Darwin's day indicated that 

 a greater variability of the male occurred in the majority of the 

 groups of data investigated. And when I considered that this greater 

 organic variational tendency of men is apparently true of psychic 

 variations also of genius, of idiocy and other mental anomalies 

 having an organic basis it seemed to me that in the greater varia- 

 tional tendency of man we are in the presence of a fact that has 

 social and practical consequences of the widest significance, a fact 

 which has affected the whole of our human civilization. Although 

 the greater variational tendency of men is balanced by the more 

 equable level of women, we have to recognize that the existence of the 

 exceptional men who have largely created the lines of our progress is 

 based on natural law. It is a conclusion which does not yet appear 

 to me to be fundamentally affected. 



There was, however, one important omission in my statement 

 of this question, and I wish to emphasize the importance of the 

 omission because its significance will subsequently become apparent 

 to the reader. I said little or nothing as to the variability of men 

 and women in size, either as regards total stature and weight, or 

 the dimensions of parts of the body.* The reason for that omission 

 is clearly indicated in various parts of the volume and we shall en- 

 counter it in due course. 



Three years later, in a volume of miscellaneous essays entitled 

 'The Chances of Death,' Professor Karl Pearson published a lengthy 

 paper entitled 'Variation in Man and Woman.' This writer started 

 with the assertion that in 'Man and Woman' I had 'done much 



* I did not consider that such evidence must be absolutely rejected I 

 admitted it in one or two cases (printed in smaller type) but simply that as 

 it was liable to a discount of unknown extent it could not be placed in the first 

 rank of evidence. 



