SEXUAL HORMONES AND MORPHOGENESIS 469 



GENETIC SYSTEM OF SEX CHARACTERS. 



Tandler and Gross, do not supply definite proof of a dependence 

 of the generative cells upon sex hormones. Herrmann (1915, 

 p. 36 and 44) found that folhcular development can be stimu- 

 lated in young rabbits when extract of corpus luteum is 

 injected. In the freemartin, where hormones of the opposite 

 sex are supposed to circulate in the organism of a female, 

 there is also an influence on the sex gland, in this case an 

 influence of male hormones on the generative part of the ovary 

 (Keller and Tandler, 1916, footnote on pp. 513-14; Chapin, 1917) 

 The observations of Willier (1921) on the sex gland of the free- 

 martin made it probable that there is in this animal an actual 



