HORMONES 53 



were then allowed to grow to maturity and 

 the development of the secondary sexual char- 

 acters was closely watched. (Plate I.) The 

 implanted ovaries, even though simply under 

 the skin, grew and ripened. None of these ani- 

 mals developed male secondary sexual charac- 

 ters ; the male external genitalia, for instance, 

 remained immature, and the body assumed the 

 form of the smaller sex, the female. The growth 

 of hair and the deposition of fat were in the 

 direction of the female type. The mammary 

 glands, the nipples, and their surrounding 

 areolse were typically female. None of these 

 animals showed the characteristic male sexual 

 excitability even in the presence of a female 

 in heat. They very commonly did exhibit the 

 " tail reflex " and the " protective reflex," both 

 characteristics of the female, and they were 

 sought by males, though of course ineffec- 

 tively. Thus, so far as the secondary sexual 

 characters were concerned, a male animal had 

 been converted, both structurally and func- 

 tionally, into a female. 



When in a very young male animal the 

 testes were transplanted from one region to 

 another, development was seen to proceed 

 along normal lines. Such an animal in the 



