28 GONADECTOMY IN RELATION TO THE SECONDARY 



taining spermatozoa was found attached to the abdominal wall. The 

 sites of the testes were empty. The other bird, externally, was char- 

 acteristically a capon and did not differ from his mates. At death no 

 trace of testicular material could be found. In all four the normal male 

 plumage had developed, except that the feathers were longer. The 

 spurs, too, were well developed. The comb and wattles, however, 

 remained small, though of course not of the size they were when the 

 operation was performed. The two kept for over 4 years have interest- 

 ing histories. When 18 months old their combs began to grow rather 

 rapidly and continued to grow for several months before ceasing. 

 During the winter of 1913-14 the combs began to grow again, but, 

 unfortunately, during the severe weather lost the points through freez- 

 ing. On this account the final size can not be accurately determined, 

 but it is obvious that they reached nearly if not quite their normal size. 



Further experience with capons shows that the comb development of 

 the bird figured by Goodale (1913, American Naturalist) is greater than 

 that which occurs in other instances, such as that shown in plate vn, A, 

 which has almost no comb development. True, the comb is not as 

 small as when the bird was castrated, but the enlargement is only that 

 necessary to correspond to the increased head size. It is now evident 

 that the comb of the bird figured in the Naturalist paper had already 

 begun to grow at that time, although for a bird 16 months of age the 

 comb shown in the figure is much smaller than that of the normal hen, 

 to say nothing of the cock. At that time it was supposed that the 

 amount of comb tissue present was due to the genetic basis in the Leg- 

 horns for a large comb. This assumption is supported by the absence 

 of testicular tissue in a mate with a similar history which was autopsied 

 and by the relatively rapid growth of the head furnishings in another 

 mate, which at autopsy had a small bit of testicle containing sperma- 

 tozoa, attached to the abdominal wall, although it lacked other tes- 

 ticular material. The capon figured in the Naturalist was killed October 

 17, 1915, when somewhat more than 4f years of age. The bird weighed 

 5J pounds and was very fat, resembling in that respect an old hen of the 

 American breeds. On either side was a mass of testicular-like material ; 

 that on the right was 18 mm. long by 10 mm. in diameter, that on the 

 left 12 mm. by 6 mm. Leading from each was a small but distinct 

 vas deferens. No spermatozoa could be identified, either in the vas 

 deferens or in the organ itself. Nor was there any evidence of sperm 

 formation. The bird was in good health and had been running with 

 hens for a long time. As far as could be made out, the " organs" were 

 in good condition. 



Although both birds had combs of similar size at the time the photo- 

 graph mentioned above was made, eventually one (No. 1177) out- 

 stripped the other, developing a comb that was only a little smaller than 

 that of a normal male. At the autopsy of No. 1177, which died on 



