1903.] The Acquirement of Secondary Sexual Characters. 57 



concerned in the production of the male characters. This graft is 

 strictly ductless, and is, moreover, entirely disconnected from its proper 

 nervous relations. 



But much smaller grafts than any of these may be met with in 

 imperfect castration, and in such circumstances the male characters are 

 correspondingly ill-pronounced. One must in fact regard the external 

 character of maleness as a quantity which varies proportionally with 

 the amount of gland-tissue present. As an example of a minimal 

 development of such characters associated with a correspondingly small 

 amount of gland-tissue, we may adduce the following observation : — 



A cockerel (impure breed of Plymouth Rock) was castrated when 

 about 6 weeks old. The bird was killed 10 months after the date of 

 the operation, when it exhibited the following characters. The head 

 presented no male development of comb or wattles. As indications of 

 maleness, however, are the full development of the neck-hackles, a 

 certain development of saddle-hackles, the presence of a few straggling 

 badly curved feathers amongth those of the tail, and the growth of 

 short blunt spurs on the legs. It may be noted that the occurrence of 

 spurs in the hens of this breed is not known, except in the case of old 

 birds. The bird took no notice of the hens with which it was habitually 

 kept. 



On dissection, no trace of either testicle was discovered at the normal 

 site, and no graft, with the exception of a minute nodule the size of a 

 hempseed, which was adherent to the surface of one of the coils of 

 intestine. Microscopic examination of this minute nodule proved it to 

 consist throughout of testicular tubuli distended with epithelial cells 

 and large numbers of spermatozoa, spermatogenesis being in active 

 progress. 



Conclusions. 



From the fact that in the young of the Herdwick sheep and fowl, 

 occlusion of the vasa defer entia does not inhibit the full acquirement 

 of secondary male characters, it is clear, in the first place, that the 

 discharge of the sperm is not in any way the factor responsible for the 

 production of the characters referred to. 



This conclusion admits of being extended to mean that the produc- 

 tion of secondary characters is not due to metabolic changes set up by 

 a nervous reflex arising out of the mere physical function of the sexual 

 mechanism. This is made still more forcible by the results of 

 incomplete caponisation in those cases where the grafts were found in 

 situations far removed from the normal, and altogether disconnected 

 from the nerve supply proper to the testicle in its natural position and 

 connections. 



Such grafts, devoid as they are of any channels communicating 

 externally, and consisting as they do, of tubuli only, are virtually 



