CHAPTER III 



SEX AND SEX DIFFERENCES AS QUANTITATIVE 



Intersexes in moths ; Bird intersexes ; Higher metaboHsm 

 of males ; Quantitative difference between sex factors ; 

 Old ideas of intersexuality ; Modem surgery and 

 human intersexes ; Quantitative theory a Mendelian 

 explanation ; Peculiar complication in the case of 

 man ; Chemical life cycles of the sexes ; Functional- 

 reproductive period and the sex problem ; Relative 

 significance of physiological sex differences. 



Crossing European and Japanese gypsy moths, 

 Goldschmidt (i, 2, 3, 4) noticed that the sex 

 types secured were not pure — i.e., that certain 

 crosses produced females which bore a distinctly 

 greater resemblance to the male type than 

 others, and vice versa. One of these hybrids 

 of " intersexes," as he calls them, would always 

 possess some female and some male sexual 

 characters. He found that he could separate 

 the males and females, respectively, into seven 

 distinct grades with respect to their modification 

 toward the opposite-sex type, and could produce 

 any one of these grades at will by breeding. 



For example, the seven grades of females 

 were roughly as follows : (i) Pure females ; 



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