74 



FRANK R. LILLIE. 



derived from atretic follicles. If this view should be confirmed, 

 the time of first formation of specific female sex hormones would 

 be postponed in most species until after birth. 



Doncaster's suggestion (1920) that the tortoise-shell tomcat 

 may be a female transformed by hormones of a male partner in 

 foetal life has been dealt with by C. C. Little (1920, 1921), who 

 finds no vascular 'connections between the membranes of foetal 

 cats. The suggestion, however, leads me to emphasize the finding 

 that conditions in the free-martin, which offer probably the most 

 favorable possible opportunity, do not lend themselves to the idea 

 that complete sex inversion by hormones is a possible thing. I 

 am led to emphasize this because Julian Huxley (1922, pp. 201 and 

 214) also states, basing his statement on the free-martin, that 

 hormones may produce all stages of conversion of one sex into the 

 other. Although I have paid particular attention to this point, I 

 have been able to find no evidence for it. On the contrary, the 

 conversion of the female sex in the case of the free-martin stops 

 very far short of complete inversion. There is a wide gap between 

 the most extreme case and the normal male, and the statistics do 

 not favor the suggestion that in some cases this gap may be crossed 

 at a bound, leaving no intermediates (cf. p. 50). I believe, how- 

 ever, that proper caution admonishes us to realize that the limits 

 of hormone action may vary, even widely, in different species. 

 Both Steinach and Moore, for instance, find considerable differ- 

 ences between the rat and guinea-pig in the feminizing effect of 

 ovarian grafts on castrated infantile males. I do not, therefore, 

 mean to deny the possibility of complete sex inversion by hor- 

 mones for all species, but merely to emphasize that the case is not 

 proved for any species. 



So far it has not been shown that the explanation of the inter- 

 sexual condition in the free-martin is of wider application for the 

 explanation of intersexuality in mammals. The theories must, 

 however, develop along two main lines, viz. : either that of unbal- 

 anced sex factors or of unbalanced hormones. The former is a 

 problem in genetics, which will be advanced by actual breeding 

 experiments, for which goats seem to offer unusual advantages 

 owing to the relative abundance of hermaphrodites in certain 

 breeds, and the negative evidence against the theory of unbalanced 



