20 GONADECTOMY IN RELATION TO THE SECONDARY 



No. 186. The history of this bird is similar to the preceding. The 

 testes were completely removed when the bird was 4 weeks of age. In 

 1913, 1914, and 1915 the bird molted but did not assume the summer 

 plumage. At autopsy no trace of the testes could be found. It is of 

 some interest to note that the molt took place at the same time of year 

 in 1913 as that of No. 171, though No. 186 was 3| months younger. 



Maib Ducks Partially Oechidotomized. 



The history of the cases where the removal of the testes, intention- 

 ally or otherwise, was incomplete may be considered here in condensed 

 form. 



No. 119. August 9, 1912, the left testis was removed. June 10, 

 1913, the bird was found to be assuming the summer plumage. July 

 10, when the bird was in full summer plumage, he was killed. On the 

 left was some testicular material. The vas deferens of this side was 

 small and straight and scarcely visible. On the right was an immense 

 testis, fully twice the size of that of a normal male. The vas deferens 

 was convoluted and contained semen, but was not as large as usual. 

 Penis and syrinx were normal. 



No. 136. Left testis removed in several pieces, June 13, 1912. On 

 July 1, 1913, the bird was killed while in full summer plumage. Vasa 

 def erentia small, not easily seen. On the left was a small testis about a 

 third the diameter of a normal testis, but of full length and irregular in 

 shape. The right testis was normal, though a little irregular in shape. 



No. 172. The testes were removed June 29, 1912. The epididymi 

 were probably left behind, nor was it certain that all testicular material 

 was entirely removed, though the sites of the testes were carefully wip ed 

 off. Whatever testicular material was left behind was not visible to 

 the naked eye. June 10, 1913, the bird began to molt and to assume 

 the summer plumage. August 10, when in full summer plumage, he 

 was killed and dissected. On the site of each testis was a relatively 

 small amount of testicular-like material containing numerous vesicles 

 of approximately equal size filled with a yellowish fluid. The vasa 

 deferentia were found with difficulty. They were very infantile and 

 non-convoluted. The penis was rather small and contained only a 

 Uttle mucus. 



It is perfectly evident that the male after castration often does not 

 assume the summer plumage, but a number of points remain to be 

 cleared up. While the sites of the testes have been found entirely 

 empty in several instances where the summer plumage has not been 

 assumed, there are also several cases where material has been found at 

 autopsy on the site of the testes. While the histological examination 

 of this material is not yet complete, it is probably not spermatogenic. 

 On the other hand, where the males have assumed the summer plumage 

 after castration, material that looks much Uke that just noted is always 

 found. In several such instances, seminal tubules with spermatozoa 



