356 INTERNAL SECRETIONS 



interest in this connection; in guinea pigs, so suitable for 

 demonstrating the feminizing effect of ovarian hormones. 

 Sand found in three cases of intratesticular transplantation, 

 persistence of normal ovaries without any influence on the 

 sex characters having been exhibited. This statement of Sand 

 was recently confirmed in our laboratory by Voss. It seems to 

 me very hkely that the fate of the graft and its hormonic effect 

 are not necessarily concomitant phenomena. The hormonic 

 effect of the graft depends evidently upon quantitative relations 

 between the two heterosexual glands. The experiments 

 hitherto made were such as did not admit of the possibility of 

 making definite statements on this point, but the question 

 seemed to me well worthy of experimental study, in which the 

 quantities of the respective grafts should be varied. 



With Krause and Voss I made an extensive experimental 

 study of this question in guinea pigs on quantitative lines. 

 These experiments proved (LipscMUz and Krause, 1923 ; Krause^ 

 1923) that an ovarian fragment can survive and reveal a 

 maximal feminine hormonic effect when engrafted by the 

 intratesticular method of Sand, both testicles being present 

 in the body. If one testicle is removed previously to the 

 ovarian implantation, the number of successful cases is 

 highly increased and the time of latency, i.e., the time between 

 the operation and the first appearance of the hypertrophy of 

 the teats, is much diminished. If previously to ovarian trans- 

 plantation the testicular mass is so far reduced that only a small 

 testicular fragment is present in the body, which, however, is 

 sufficient for normal masculinization, there will be almost 

 100 per cent, of positive cases, i.e., the fragment will "take" 

 and exhibit its hormonic effect practically in all the cases 

 operated (unpubUshed experiments with intrarenal ovarian 

 grafts^, experiments with Voss). The time of latency is so 

 extraordinarily diminished, under the indicated quantitative 

 conditions, that the hormonic effect of the ovary may reveal 

 itself as early as 12 to 14 days after implantation, even when 

 the ovary is taken from an animal only two weeks old. Our 

 experiments leave no doubt that ovarian fragments can resist 

 against two testicles in situ and that testicular fragments can 



* Intrarenal ovarian grafts were first made by Marshall and Jolly (1908). 

 The technique I adopted differs in some respects from the original method of 

 Marshall and Jolly. 



