78 INFLUENCE OP HORMONES 



rudiments visible in adult hens. This is the age 

 at which castration is usually performed, as at an 

 earlier age the birds are too small to operate on 

 successfully. It follows, therefore, that the spurs 

 develop after castration, and it would seem that 

 their development does not depend upon the 

 presence of the sexual organs. It is a question, how- 

 ever, whether castration in the cock is ever quite 

 complete. In the original wild species and in the 

 majority of domesticated breeds the spurs are con- 

 fined to the male sex, and are typical secondary sex- 

 characters, as much so as the antlers of stags or the 

 beard of man, yet the above discussion shows that 

 there is some doubt whether their' development is 

 prevented as much as in other cases by the absence 

 of the sexual organs. Even if it should be proved 

 that in supposed cases of complete castration, such 

 as that of Shattock and Seligmann, some testicular 

 tissue remained at the site of the testes, it would 

 still be true that the development of the comb and 

 wattles is more affected by the removal of the 

 sexual organs than that of the spurs or tail feathers. 

 My own experiments in castrating cocks were as 

 follows: On August 20, 1910, I operated on a White 

 Leghorn cock about five months old. One testis 

 was removed, with a small part of the end broken 

 off, but the other, after it was detached, was lost 

 among the intestines. On the same day I operated 

 on another about thirteen weeks old, a speckled 

 mongrel. In this case both testes were extracted 

 but one was slightly broken at one end, although 

 I was not sure that any of it was left in the body. 

 An entire White Leghorn of the same age as the first 

 was kept as a control. On August 27 the two 



