462 INTERNAL SECRETIONS 



manifestation of male sexual instincts in a castrated cock 

 by implantation of the testicle of a pheasant (P. versicolor); 

 there was some evidence also of a feminization of a castrated 

 cock after implantation of an ovary of a pheasant. The 

 experiments of Steinach, who obtained an erotization of 

 castrated Rana temporaria by introducing a pulp of testicle from 

 R. esculenta may also be mentioned here. The successful 

 transplantation of apes' testicles on man as made by Voronoff 

 (1923) and by Thorek (1922) is further evidence. I had the 

 opportunity of personally observing a man in whom the testicle 

 of a goat was transplanted in the muscular wall of the abdomen, 

 and in whom a marked erotization took place. Various 

 anthropological facts also are evidence of the non-existence of a 

 species specifity of the sex hormones. There are in men and 

 women of most races certain sex differences which, though 

 absent at time of birth, develop during extrauterine life. 

 These sex differences are very pronounced in all human races, 

 and they are invariably of the same order {Martin, 1914, p. 331). 

 The body height of the female is in all races less than that of the 

 male. And so with the length of the extremities and those of the 

 hands and feet. On the contrary, in all human races the pelvis 

 in the female is broader than in the male. Many of these sex 

 differences have nothing to do with propagation. As certain of 

 them depend upon the sex specific hormones it must be 

 assumed that the latter are similar in the different human races. 

 The above assumption does not imply, however, that there 

 can be no differences at all betv/een the sex specific hormones in 

 various species. The question needs further experimental 

 investigation, being of great importance in studying heredity. 

 Pezard and Caridroit (1922 a) assumed that the hormones of the 

 ovary, besides their general action on the plumage of the neutral 

 form, may also possess an inhibitory action on characters of a 

 given race. They performed the following experiments : — 



Experiment A. ' Experiment B. 



Male Leghorn X Female | Male Dorking X Female 

 Dorking. j Leghorn. 



Fj ! (J — mixed plumage with 3 — mixed plumage with 



characters of Leghorn i characters of Leghorn 



and Dorking. | and Dorking. 



$ — plumage of pure Leghorn ' $ — ^plumage of pure Dorking 



