., 



THE ORGANS OF REPRODUCTION 97 



,ve been destroyed. When the animal is cas- 

 trated, which involves removal both of the external 

 and internal glands, it loses its antlers. Clearly 

 then the result of castration must be attributed 

 to the loss of the interstitial hormone. 



From the evidence presented we may conclude 

 that the hormone or hormones that give rise to the 

 male characteristics are due to the interstitial 

 gland. The hormone is elaborated by the gland and 

 passes directly into the blood stream. We are here 

 therefore dealing with a gland belonging to the 

 "ductless" group. 



Professor Biedl says that "it is highly probable 

 that, by the agency of its secretory product, the 

 interstitial gland is responsible for the develop- 

 ment of the male sexual gland from the indifferent 

 genital trace. That it has a determining influence 

 upon the normal development and maturity of the 

 generative portion of the sexual gland, upon the 

 formation of the secondary genital organs, and 

 upon the existence and persistence of those morpho- 

 logical and biological characters which are the 

 property of the male sex, is undoubted." 



Our information regarding the interstitial cells 

 of the female is meager, but whatever we do know 

 points to their presence, and to their possessing a 

 function similar to the cells of the male. 



Grafting. Brown- Sequard's suggestion that the 

 active genital glands impart vigor to the body, due 



