19 8 E. UHLENHUTH 



(Bouin and Ancel, Steinach) and the interstitial cells and corpora lutea 

 of the ovary (Bouin and Ancel, Steinach) elaborate the sex hormones ; the 

 sex gland is differentiated into a generative and a glandular (interstitial 

 gland) structure (Fig. 4 and Fig. 5). 



The sex hormones are specific ; the male hormone produces only the 

 male, the female only the female characters, as demonstrated especially 

 by Steinach's important experiments. Ovaries grafted into male rats 

 castrated at an early stage produce only the female characters and may 

 serve to suppress even such male characters as would develop after castra- 



lug. G. A normal and a castrated male guinea pig; into the latter two ovaries 

 were grafted subcutaneously (note the prominent areas on the abdomen) and caused 

 feminization of the male (development of the female pregnancy type of the mammary 

 gland). Demonstrates specific action of the female sex hormone. After Steinach. 



tion (Fig. 6). The same fact is shown by Lillie's discoveries in the 

 female free martin of cattle, which, through the action of the male 

 hormones becomes changed in varying degrees into a male. In amphibians 

 such specific action has been denied by Harms and by Meisenheimer, 

 though, as it seems, on the basis of too small a number of experiments. 



In mammals there exists an antagonism between the sex glands in 

 that the presence of one may be destructive to the other (Steinach, Lillie), 

 although for a short time both may exist in a functioning condition in 

 the same individual, if the nutritional conditions are equally favorable 

 to both (Steinach (e), Sand). This may result in the simultaneous devel- 

 opment of male and female secondary sex characters in one individual. 



Probably the sex hormones, like other hormones, are non-specific as 

 regards the species from which they come. Pezard prevented the effects 

 of castration in male domestic fowls by the injection of pig's testiple. 



