214 INTERNAL SECRETIONS 



cells may even in some species decrease after the first corpora 

 lutea have appeared; this he stated to be the case for the dog 

 and for the cat (Fig. loi); he says that whereas the interstitial 

 tissue in the ovary of the dog when stained with "Sudan" 

 becomes gradually more accentuated till puberty, so that the 

 ovary is full of cells with red granules of fat, these cells cannot be 



Fig. 96. — Interstitial tissue in the ovary 0} Phascolomys [Marsupialia). 

 Photo, low magnif. The epithehoid cells of the stroma are disposed 

 in the form of lobules. On the left a degenerated ovum is to be seen 

 in the middle of a lobule, the lobules being nothing else than follicles 

 undergoing atresia. — From L. Fraenkel. 



detected any longer by the usual methods at the time of the 

 first heat. In the cow, sheep, goat, horse, ape and man there 

 is, according to Aschner, only a rudiment 6i an interstitial 

 tissue, if compared with that of the ovary in the species 

 mentioned above. As Aschner points out, there seems to be a 

 parallelism between fertility and quantity of interstitial cells 

 in the ovary. Those species in which, as in the rabbit, hedge- 

 hog, bat and others, the number of the young in each htter is 



