82 INTERNAL SECRETIONS 



medicine, they were not brought into relation with other similar 

 phenomena, and so they had no influence on scientific thought, 

 and temporary oblivion was their inevitable fate. 



New experiments with transplantation were made about 

 fifty years later by Foges (1902) on cocks. He succeeded in 

 completely removing the testicles in two cases and trans- 

 planting them into another position in the abdominal cavity. 

 Foges relates that these animals appeared to stand midway 

 between a normal cock and a capon, the head apparel being 

 smaU and pale, while there was an increase of fat, but the 

 spurs and plumage of the cock were well developed. Foges 

 concluded from this experiment that there is an internal 

 secretion produced by the testicle, but that the sexual 

 characters were only partly developed in his birds because the 

 engrafted testicular mass was smaller than that of the normal 

 testicles. But from what we know today of the results of 

 castration in the cock it is clear that in reality the two birds 

 became capons and that autotransplantation had not succeeded. 

 Homoiotransplantation was also attempted by Foges without 

 success. 



New and careful experiments have been made on cocks by 

 Pezard (1911, 1918, pp. 91-98). After having completely 

 removed the testicles of birds five months of age, the organs 

 were cut into small pieces and replaced in the abdomen. At 

 first there were signs of castration; a regression of the comb 

 began, sexual instincts and crowing did not develop, though 

 already manifested in the control animal. But about a month 

 after the operation the experimental birds were normal in 

 regard to head apparel and sexual behaviour. Pezard con- 

 tinued his observations for two months longer without observing 

 any abnormality in his animals. 



Whereas it is very difficult to remove completely the testicle 

 in the cock, castration in mammals can be done without any 

 difficulty. But on the other hand it seems that in the mammal 

 the testicle does not "take" so well as in the cock. Many 

 experiments have been made by different investigators on the 

 dog, rabbit and rat (Biedl, pp. 282-284). These experiments 

 were not always successful, even when an autotransplantation 

 was made. Positive experiments, however, with autotrans- 

 plantation have been described by Steinach (1910). He 

 operated on 40 rats from three to six weeks old; in 36 cases 



