416 FRANK R. LILLIE 



in the absence of male hormones. These facts must be kept 

 clearly in mind as definitely fixing the very provisional character 

 of such speculations as we may make. 



The present standpoint for the analysis of sex-characters of 

 mammals would have to include (1) primary zygotic determina- 

 tion of the male and female sex and (2) secondary differentiation 

 of the sex characters, in which internal secretions play a very 

 specific and fundamental role. The production of intermediate 

 zygotic conditions is theoretically possible, since Goldschmidt has 

 demonstrated all grades of inter sexuality in the gypsy moth de- 

 pending on variable conditions of the gametes. But it is obvious 

 that such conditions are not involved in the present case and 

 that we have to consider only the secondary factors. 



It follows from the data that the female zygote must contain 

 factors for both sexes ; the primary determination of the female sex 

 must therefore be due to dominance of the female factors over 

 the male. If we think of this as a simple quantitative relation, 

 as Goldschmidt ('16) has done, we can explain the intersexual 

 condition of the free-martin as due to an acceleration or inten- 

 sification of the male factors of the female zygote by the male 

 hormones. The degree of the effect which is quite variable, as 

 we have seen, would of course be subject to all quantitative 

 variations of the hormone. Thus the case of the free-martin 

 could come under the same general point of view as that of 

 the intersexes of Lymantria according to Goldschmidt with the 

 one exception that the quantitative differences between the male 

 and female factors of the female zygote necessary for the differ- 

 entiation of female characters, are reduced in the free-martin by 

 internal secretions instead of by variations of potency of the 



hormones during foetal life, or they are neutralized in some way, or the placenta is 

 impervious to them. The first possibility does not seem consistent with our 

 knowledge of the physiology of the mammalian ovary, or with the cytology of the 

 organ during pregnancy; the second one offers no point of attack at present; the 

 third seems the most probable a 'priori, and is no doubt susceptible of experi- 

 mental analysis. ' But whatever explanation may prove to be correct it seems 

 probable that disturbance of the equilibrium that protects the male from the 

 sex hormones of the mother would result in malformations of the male sex char- 

 acters to a degree commensurate with the extent of the disturbances. There is, 

 therefore, here a possible explanation of the greater mortality among male 

 • foetuses, and of certain types of intersexes (pseudo-hermaphroditism). 



