SEX SPECIFIC ACTION OF HORMONES 291 



months and become transformed into the organ characteristic 

 of the virgin female. A further growth of the teats and the 

 glands takes place during gravidity and lactation. In the same 

 manner the teats develop in the feminized male. The teats are 

 long, thick, and red, and the area around them is shiny and 

 protruding, as in a normal female during gravidity. As shown 

 by microscopical examination the mammary glands themselves 

 really develop as in the normal female during gravidity and 

 lactation. There is sometimes even a secretion of milk which 



Fig. 114. — Influence oj ovarian transplantation on the teats of the castrated 

 male guinea pig. — Photo of Steinach. 



B. Feminized male (during period of lactation). 



can be pressed out from the gland. Such animals are sought 

 out by young ones which attempt to suck. Sometimes the 

 feminized male takes care of the 3^oung and suckles (Fig. 115). 

 The milk secretion persisted in certain cases for quite a pro- 

 longed period, but there were intervals without milk secretion. 

 Steinach's discovery has been fully confirmed by Athias 

 (1915), by Sand (1918, 1919), by Moore (1919 a, 1921) and by 

 Harms (1922), by Lipschutz and Krause (1923 b and c) and by 

 Lipschutz and Voss (unpublished experiments); the state- 

 ments of these authors differ from those of Steinach only in 



