140 



Dr. A. Lipschiitz and others. 



fact that a " backward development " of the testicle is possible under experi- 

 mental conditions. 



III. 



After all, there can be no doubt that the hypertrophy of the interstitial 

 cells, as observed under different experimental conditions, has nothing to do 

 with the function of the testicle for the organism as a whole, but that this 

 hypertrophy is caused only by local conditions in the testicle itself. 



Kyrle (12), who studied the hypertrophy of the interstitial cells under 

 different experimental conditions, has suggested that this hypertrophy has 

 something to do with a regeneration process which the seminiferous tubules 

 are undergoing. This point of view is in connection with another conception 

 of the function of the interstitial cells, namely, that these cells represent 

 a trophic organ for the seminiferous tubules. The latter conception plays a 

 great role in the attacks, made in the last few months by different German 

 authors (13), upon the theory of Bouin and Ancel (which was supported 

 and further developed by Tandler, Steinach, Sand and myself) that the 

 interstitial cells are an organ of internal secretion. 



This is not the place to discuss the question whether our conception of the 

 internally secretory function of the interstitial cells is right or not. Indeed 

 this conception will not remain unaltered and it is impossible now to say how 

 much of this theory will permanently stand in view of the further develop- 

 ment of scientific research in our special field. And, it may be, the results of 

 the experiments made in our laboratory and reported by myself in this com- 

 munication will be interpreted by some as a withdrawal in some measure 

 from the position I held and tried to strengthen in my book on the " puberty 

 gland." But on the other hand I think that there are not yet sufficient 

 data to attribute definitely to the interstitial cells a special local function in 

 relation to the seminiferous tubules, although the possibility of such a function 

 cannot be denied, even though the interstitial cells should play a rSle as an 

 organ of internal secretion. It is necessary for us to emphasise this point 

 since Stieve in a recent publication (13) has seriously misrepresented our 

 views. 



Summary. 



In experiments with partial castration one may observe in small testicular 

 fragments enormous hypertrophy of the interstitial tissue, the number and 

 the size of the interstitial cells being very markedly augmented. This hyper- 

 trophy is not a compensatory one, as is shown by the following experimental 

 evidence : — 



A. Hypertrophy of the interstitial cells is not present in all cases of partial 

 castration and very small testicular fragments with a not very much 



