On the Interstitial Cells in Testicle of Guinea-Pig. 133 



animal of the same age. Sand showed that the remaining testicle can 

 undergo the same hypertrophy even when the vas deferens is ligatured ; this 

 is due to the fact that, even after the vas deferens is ligatured, the 

 spermatogenesis can proceed in a normal way, and the degeneration of the 

 tubules begins only when the spermatogenesis is more or less completed. So 

 one may object that, when the testicular mass is diminished, there is 

 hypertrophy not only of the interstitial cells but also of the seminiferous 

 part. This is why I said, two years ago (7), that the situation seemed to be 

 more complicated than Bouin and Ancel supposed, basing their conclusions 

 on ingenious experiments, performed about twenty years previously, when 

 nobody could foresee the extraordinary development which the study of the 

 internal secretion of the sexual glands has undergone in recent years. 



We again took up the question of the hypertrophy of the interstitial 

 cells in the testicle in connection with another problem of internal secretion 

 of the sexual glands. We studied the question as to how the development 

 of the sexual characters of mammals depends upon the quantity of secretion 

 of the sexual glands present in the body. For this purpose we used a 

 method consisting of making unilateral castration and of cutting away more 

 or less from the second testicle (" partial castration ")(8). We made a great 

 many of these same experiments on guinea-pigs, and we were able to state — 

 in accordance with Pezard (8a) — that even very small particles, representing 

 1 or even less than 1 per cent, of the normal testicular weight, are sufficient 

 for a normal masculinisation of an animal (9). In some cases we observed 

 that the development of the sexual characters was slower than normally ; 

 but we have experimental evidence that this phenomenon of retardation 

 was caused, not by a simple quantitative deficiency in internal secretion, 

 but by a slower development of the sectioned testicle (10). 



In all these experiments we had theoretically to confront a very important 

 complication, i.e., the possibility of a compensatory hypertrophy of the 

 elements, to which we ascribe the function of internal seci'etion in the 

 testicle. And indeed in some cases where the particles were especially 

 small, we found an extraordinary development of the interstitial tissue. 

 The size and the number of the interstitial cells may sometimes be enormous. 

 In such a small segment of the upper pole of the testicle, nourished by the 

 arteria spermatica interna, the number of interstitial cells may no doubt 

 attain, or even greatly surpass, the number of interstitial cells in two 

 normal testicles together, although such a particle represents, as mentioned, 

 not more but even less than 1 per cent, of the weight of two normal testicles. 



I never saw such an enormous hypertrophy of interstitial cells as in these 

 small particles in upper partial castration ; only one such case of enormous 



vol. xcm. — B. L 



