INTERNAL SECRETION OF TESTICLE i6i 



1922 a, 1923 e). From the results of a detailed study made on 

 the hypertrophy of the testicle after unilateral castration it 

 seems further very likely that the increase of weight observed in 

 young animals in this experimental condition is not an hyper- 

 trophy at all but a phenomenon of a very different kind (1922 c). 

 (Fig. 85). Further, Lipschiitz and Ibrus (1923 c, d) have shown 

 that no change in the quantity of the interstitial cells takes 

 place after unilateral castration. The remaining testicle 



4.0 



3.5 



3.0 





in 



I 



t.O 



0.5 



/^ 



500 1000 



Body we'iojht or 



1500 



2000 



2500 



3000 



Fig. 85. — Diagram to illustrate the hypothesis that the so-called com- 

 pensatory hypertrophy of the remaining testicle is on'y an acceler- 

 ated growth. The thick hne indicates the real curve of growth of 

 testicle in the normal rabbit ; the thin line shows the supposed 

 curve of growth of the remaining testicle after prepuberal uni- 

 lateral castration; this curve is the normal one removed to the 

 left. The difference between a normal and a remaining testicle 

 is supposed to increase gradually and after a maximal differ- 

 ence is attained at time of puberty, to decrease again gradu- 

 ally. Different points of the supposed curve have been verified 

 by experiments. 



reveals" a structure (Fig. 86) quite identical with that of a 

 normal one. It may be mentioned that in the frog the testicle 

 or the testicular fragment seems to react differently from the 

 way it does in the mammal (Lauche, 1915); in the frog the 

 testicular fragment undergoes hypertrophy. 



No matter where the seat of the endocrine function of the 

 testicle is situated, no compensation seems necessary in the 

 mammal for the performance of the normal internal secretory 



