154 INTERNAL SECRETIONS 



extension of the seminiferous part of the testicle. As was 

 shown by Simmonds, mesothorium acts Hke X-rays. 



In view of these phenomena of regeneration, Simmonds 

 concluded that the internal secretion is produced by the sper- 

 matozoa, and that the interstitial cells take up this function 

 only when the seminiferous tubules of the testicle are partially 

 destroyed. I do not deny that these experiments with X-rays 

 are insufficient for demonstrating that the occurrence of different 

 stages of developing spermatic ceUs is not correlated with the 

 production of the internal secretion of the testicle ; irradiation 

 seems to be a very uncertain means of destroying the semini- 

 ferous tubules, depending greatly upon strength and duration. 

 We have no guarantee that in all the experiments with X-rays 

 recorded hitherto a more or less extended regeneration has 

 been avoided. But in 19 16 a Russian author, Nemenov, 

 published a paper which has not yet been taken into considera- 

 tion in the criticism directed by different authors against the 

 theory of the "interstitial'* or "puberty" gland. Nemenov 

 irradiated dogs repeatedly and examined the testicles and the 

 prostate a long time after the last irradiation. Nemenov 

 stated that even more than eight months after the last irradia- 

 tion only cells of Sertoli were present in the seminiferous 

 tubules. Nevertheless, the prostate was very well developed, 

 many mitoses were present and the tubules of the prostate 

 were full of secretion. The paper of Nemenov is of great 

 importance in its bearing upon the question, and taken in 

 conjunction with the experiments with ligation and trans- 

 plantation recorded above, together with our experiments 

 with partial castration, the observations of Nemenov supply 

 further evidence that seminal cells are not directly involved in 

 the internal secretion of the testicle. Further, Ancel and Bouin 

 (1923) irradiated young guinea pigs and kept them till nine 

 months after irradiation. Though the seminal tubules were in 

 an infantile stage and generative cells were totally absent, the 

 sex characters were normal; the fluid of the seminal vesicles 

 coagulated as in a normal animal. The objection may, how- 

 ever, be made that spermatogonia were still present in the 

 tubules, or that the cells of Sertoli represent some kind of 

 primitive generative cells. But if it is so, it nevertheless 

 remains true that these generative cells alone would be unable 

 to produce the internal secretion of the testicle; we have seen 



