ANDROGENIC TISSUE 69 



None has been demonstrated in the dog, cat, rabbit, or cow. 

 It is very improbable that this tissue is limited to man and 

 the mouse, and future studies shall undoubtedly reveal an 

 analogous structure in other animals. 



The accessory bodies observed by Wiesel 676 in the reproduc- 

 tive tract of young rats are possibly androgenic tissue for they 

 disappear, according to Wiesel, with age and do not hyper- 

 trophy or support life in adrenalectomized animals 198 as they 

 should if they comprised part of the interrenal system. No 

 one has, however, confirmed WiesePs description of these 

 bodies. 335 



A tissue has also been described in the pig embryo 95 which 

 resembles the androgenic tissue of man and may represent its 

 homologue in this animal. Incomplete studies 694 on the an- 

 thrapoid apes (Orangutans and chimpanzees) also indicate the 

 occurrence of a post-natal involution similar to that of man. 



Kolmer 362 from his histological study of the adrenal of a 

 nine-month old elephant (Elephas indicus) was led to believe 

 that a process of involution similar to that which occurs in the 

 human adrenal, also takes place in this animal. His descrip- 

 tion of the adrenals of certain other species also suggests the 

 presence of an androgenic zone in the little ant-eater (Taman- 

 dua tetradactylus) , the armadillo (Dasypus septemcinctus) , and 

 the porcupine (Hystrix cristata). The thick layer of connec- 

 tive tissue which surrounds the medulla in these species is 

 analogous to that seen in the mouse after the involution of the 

 androgenic zone. The unique structure in the adrenal of the 

 oppossum {Trichosurus vulpecula), described by Bourne, 77 is 

 also suggestive of the development of an androgenic zone in 

 this species. Further work with these species will be neces- 

 sary to determine if an androgenic zone is present during the 

 early development of these animals. 



It is questionable if the involution of the cortex recently 

 described by Whitehead 673 represents the degeneration of an- 

 drogenic tissue in the rabbit.* 



*Cf., however, Jour, of Anatomy, vol. 70, p. 126. 



