234 INTERNAL SECRETIONS 



does not take place if an atrophy of the epithelioid cells of the 

 stroma was also caused by irradiation. 



The experiments of Steinach and Holzknecht have not yet 

 been repeated\ but it is desirable that they should be, in view of 

 the theoretical and practical interest involved in the questions. 

 Above all, it is desirable that we should be in a position to 

 explain the different results in the experiments of the French 

 and Viennese authors. It may be also that in the experiments 

 of the former the possibihty of "Case 3" of our scheme was 

 reahsed, but that the French authors interrupted their ex- 

 periments before an hypertrophy of the interstitial tissue 

 could take place. Furthermore, it is possible that at the 

 beginning an injury to the interstitial tissue took place (transi- 

 tion from "Case 2" to "Case 3" in our scheme). As 

 Steinach and Holzknecht pointed out, the first external results 

 of the irradiation became visible about three to four weeks 

 later, and the highest degree in the development of the 

 nipples was observed only eight weeks after irradiation. 

 Steinach and Holzknecht possibly would have arrived at a 

 negative result hke Bouin, Ancel and Villemin, if they had 

 interrupted their experiments sooner ; and possibly the French 

 authors would have attained a positive result if they had con- 

 tinued their experiments longer. Moreover, the technical 

 points we discussed above must be taken into consideration. 



New experiments with X-rays were recently made by 

 Guggisberg (1922) with the special purpose of elucidating the 

 question as to which part of the ovary performs the endocrine 

 function. Guggisberg's criticism directed against our view 

 is, in reality, in opposition to suggestions which neither 

 Steinach nor myself ever made. He concludes from his 

 experiments that the follicles act as an endocrine organ, a 

 supposition the possibility of which we have never denied. 

 Guggisberg first stated that with rabbits castration leads to an 

 increased sensibility to adrenaline; about a month after 



^ Since this was written Rahel Plant (1923) communicated similar experi- 

 ments. The statements of Steinach and Holzknecht were fully confirmed as 

 to the changes in the uterus and the mammary gland occurring after irra- 

 diation. There was no hypertrophy of the uterus and of the mammary gland 

 when castration was previously performed. But according to Plaut the 

 hypertrophy of the mammary gland failed to occur also in the case when 

 only the uterus was previously removed. She assumes that the ovary acts 

 on the mammary glands through the intermediation of the uterine mucosa. 

 But this conclusion is in contradiction to what we know from the feminized 

 male guinea pig. See Chapter VI. 



