294 



INTERNAL SECRETIONS 



gr 

 400 



370 



320 



270, 



Athias performed the following experiment. Three days 

 after the beginning of milk secretion he removed the ovarian 

 grafts. The milk secretion persisted for nine days; then the 

 mammary glands began to regress, and in about a week the 

 regression was already very pronounced. 



It may be mentioned that the sex specific influence of the 

 ovary on the teats and the mammary glands cannot be studied 

 on the rat, as no teats are macroscopically visible in the male 

 rat {Myers, 1917). 



Steinach describes also the changes which the feminized 

 animal undergoes in body weight and body proportions. 



According to King and 

 ^ Donaldson (see Donaldson, 



1915) a striking difference 

 in body weight between the 

 male and female Norway rat 

 f ^ may be observed at an age 

 r ^ of about three months. 150 

 days after birth the male 

 J^ has body weight about 60 

 gr. greater than that of the 

 female; at an age of 365 

 days this difference is about 

 85 gr. In adult guinea pigs 

 the difference between male 

 and female may be as much 

 as about 200 gr. to the 

 advantage of the male. 

 According to Steinach the 

 feminized male rat has a much lower weight than that of a 

 normal male or a "castrate" (Figs. 116 and 117), and he 

 concludes that the weight of the castrated male is inhibited 

 by the ovarian graft, the growth capacity becoming Hke that 

 of a female. Similar observations were made by Steinach on 

 the guinea pig. One might object that this inhibition of 

 growth is caused not by the ovarian graft, but rather by the 

 operation itself when performed on such young animals; 

 but Steinach has pointed out that there was no inhibition 

 of growth in those cases in which the ovarian graft did not 

 "take." There is, according to Steinach, an even greater 

 difference in body weight between a normal male and a 



220 



,'-l . ; I I ] I I U I . j~.ill 



182 



214 



246 



278 



150 

 days 



Fig. 116. — Body weight of normal and 

 feminized male rats. At an age of 9 

 months the feminized animals 

 weighed about 100 gr. less than 

 normal males. — Drawn from figures 

 of Steinach (191 2, table i, p. 94). 



