SEX SPECIFIC ACTION OF HORMONES 309 



the testicle remained in the feminized animal. The latter 

 conclusion is, I think, the most probable. Experiments per- 

 formed by Pezard support this assumption. 



In an experiment in which ovaries were implanted in a 

 castrated cockerel, Pezard (1918, pp. 147-52) described a 

 slower growth of the spurs, whereas the comb and the plumage 

 remained male. The sexual instincts, which disappeared after 

 the operation, reappeared later. The autopsy showed that the 

 castration of the cockerel was an incomplete one. It is possible, 

 however, that the slower growth of the spurs was caused by 

 the engrafted ovary exerting a feminizing action for a certain 

 time. Pezard performed also experiments upon the trans- 

 plantation of testes into castrated hens; but here too 

 castration was not completely effectual. Both hens with en- 

 grafted testicles exhibited a female plumage; no spurs were 

 present. But in one case the comb was much bigger than in 

 a normal or castrated hen, and the curve of growth of the comb 

 resembled that of a normal cock. Evidently there was an 

 endocrine action on the part of the engrafted testicle in the 

 incompletely castrated hen, a condition of hermaphroditism 

 or intersexuality such as possibly existed also in some of the 

 above-mentioned experiments by Goodale. Such a condition 

 of hermaphroditism was apparently present also in older 

 experiments of Foges (1903, pp. 53-54; 19^4^ P- 383; 1920). 

 Having engrafted testes into a hen (most likely a normal 

 or an incompletely castrated one) Foges observed a growth of 

 the comb and wattles similar to that in a cock. Owing to the 

 insufficient knowledge of endocrinology at that time Foges* 

 results could not be explained as due to the simultaneous 

 presence of both the male and the female gonad. 



Feminization experiments have been carried out by Goodale 

 (1918) on five drakes, of which three were definitely feminized. 

 The plumage resembled that of the normal female, excepting 

 that some feathers preserved the male characters. The femini- 

 zation of the plumage was especially pronounced on the head 

 and on the neck. The curl in the tail which characterizes the 

 normal or the castrated drake was absent in the feminized 

 animals as in the normal duck, although the feathers concerned 

 were present; further, in the feminized bird these feathers 

 were not black as in the normal drake, but brown or yellowish 

 brown. In two feminized birds the sexual instincts were 



