SEX SPECIFIC ACTION OF HORMONES 289 



In such a way, perhaps, as Sand beheves, the resistance 

 is overcome which the albuginea offers to the ingrowing 

 of blood vessels. But in spite of all these measures, the grafts 

 did not always "take," either in the experiments of Steinach 

 or in those of Sand.^ The number of the unsuccessful 

 experiments was greater than that of the successful ones. One 

 might suppose that the ovaries were in some way influenced 

 and injured by male hormones still active in the host. Sand, 

 who performed a great number of experiments, deferred trans- 

 plantation for one to five weeks after castration with a view to 

 getting the male animals as far as possible into an " indifferent " 

 or neutral condition. The chances of success, however, were 

 not improved thereby, as may be seen from his experimental 

 results. The subcutaneous transplantation on to the external 

 surface of the abdominal muscles is to be preferred to the 

 peritoneal graft, since in the first case the progress and fate of 

 the transplanted organs may be followed by external inspection 

 and palpation. We have given particulars concerning the 

 histological changes in the graft in a previous chapter. 



In a rat four weeks old the penis is still very undeveloped. 

 The prostate is just visible with the naked eye, and the seminal 

 vesicles are much smaller than in the adult animal. In the 

 prepuberally castrated animal these conditions do not 

 change much; the organs remain in an infantile stage of 

 development, although the penis may continue to grow to a 

 certain degree. Now we learned that these organs fully develop 

 if testicular implantation is made after castration. On the 

 contrary, the development of the penis, prostate and vesicles 

 is not promoted if ovaries are implanted. Steinach relates 

 that the development of these organs is even inhibited by the 

 ova.rian graft, the penis of the feminized rat being shorter 

 than that of the ordinary castrated animal. The question as 

 to whether the ovary has an inhibitory action is of the greatest 

 theoretical importance, as we have already seen when dis- 

 cussing the results of castration in birds, in which such an 

 inhibitory action is beyond any doubt. But this question 

 has not yet been studied sufficiently in mammals. I examined 

 the penis of tv/o fully grown feminized guinea pigs, operated 

 on by Steinach some years ago; I found that the penis was 



* We shall deal in detail in Chapter IX. with the supposed antagonism of 

 the sex glands. 



