STUDIES IX THE EXPEKIMEXTAL ANALYSIS OF SEX. 591 



Studies in the Experimental Analysis of Sex. 



By 



Oeoflroy Siiiitli. :VI.A., 



Fellow of Xew College. Oxford. 



(From the Department of PathoL^gv. Univer.sitv of Oxford.) 



Part 5. — On the Effects of Testis-extract Injections upon 



Fowls. 



Ix tlie ' Proceediug.s of the Koyal Societ}- of Medicine/ 

 vol. i, "Pathology/' p. 153, 1907-8, Dr." C. E. Walker 

 describe.s an experiment in which lie injected two adult 

 hens with extract of cock's testis for a certain period, Avitii 

 the apparent result that the combs grew very rapidly to quite 

 twice their original area. On ceasing the injections they 

 shrank gradually until thev nearly reassumed their original 

 size. A further experiment is alluded to in which several 

 young hens of two months' age were treated in the same 

 manner, and it is .«tated that, though the results differed 

 somewhat from the first experiment, they were entirely 

 satisfactory, but no further details, as far as I am aware, 

 have been given. 



On the strength of the above experiments Dr. Walker 

 concludes, firstly, that the hen bird possesses the potentiality 

 of developing the comb as in the male ; secondly, that there 

 is present some internal secretion in the testis which, when 

 injected subcutaneously into the hen, calls forth the produc- 

 tion of this and other secondary sexual characters j^roper to 

 the male, e.g. the wattles and temperament. 



