PHYSIOLOGICAL PROPERTIES OF GONADS 383 



stitial cells. The grafts of 68 Bl had persisted for seven months, 

 and, as indicated, consist principally of interstitial cells; the ger- 

 minal epithelium has entirely disappeared, leaving only the Ser- 

 toli cells. The condition of this graft evidently represents the 

 conditions so often described as an hypertrophy of the inter- 

 stitial gland. 



The relative effects of the grafts upon the somatic structures 

 are essentially the same in the two animals; if any different, the 

 the external genital condition was more modified in 67 Bl. In the 

 psychical reactions, also, the latter was a more vigorous male-like 

 animal than was 68 Bl. And since a slightly more pronounced 

 modification was associated with the graft in which the intersti- 

 tial cells were present in lesser abundance it does not lend support 

 to the idea that the interstitial cells are the seat of the elabora- 

 tion of an internal secretion upon which the modifications depend. 



DISCUSSION 



In former papers the writer has taken a view-point that is 

 decidedly at variance with the idea of an antagonism existing 

 between the two opposite sex glands, the chief supporter of which 

 is Steinach. 



In view of the great number of researches upon the modifica- 

 tion of the secondary sex characters of vertebrates by castration 

 experiments and sex-gland transplantation, there is no doubt that 

 many of the characteristics of the different sexes are dependent 

 upon the integrity of the sex gland for their existence. Thus 

 from ancient times the effects of the removal of the testicle from 

 a young human individual has been exemplified by the eunuch. 

 And to mention but two or three more recent researches, Stotsen- 

 burg has shown that the presence of the ovary in female rats is 

 responsible for the relatively lighter weight of the animal. In 

 the rat, at least, the testicle has no influence upon the growth 

 curve. The weight character is then influenced by one sex gland 

 alone. And in an entirely different class of vertebrates Pezard 

 ('18) has given an excellent analysis of the influence of the sex 

 glands in modifying the somatic and psychical character of the ani- 



