INTERNAL SECRETIONS 



99 



condition. Moreover, the oestrous cycle continues. Similarly 

 menstruation may continue after the attachment of a successful 

 ovarian graft in women otherwise deprived of their ovaries. 

 Both with man and animals the graft may be from another 

 individual, but transplantation is more difficult to effect in 

 such a case, although seemingly 

 favoured by close blood relation- 

 ship. Experiments with injection 

 of ovarian extract are less satis- 

 factory, but in a number of 

 instances, congestion of the 

 uterus and other indications of 

 heat or oestrus have been brought 

 about both with spayed animals 

 and also with anoestrous ones, 

 which had not been deprived of 

 their ovaries. (See p. 101.) 



The Interstitial Cells. — As just 

 mentioned, there is an undoubted 

 functional correlation between 

 the ovaries and the normal nutri- 

 tional condition of the uterus. 

 Furthermore, there is evidence 

 that the ovarian elements 

 responsible for maintaining this 

 condition are the interstitial cells, 

 for MTlroy and others have 

 shown that the normal condition 

 is preserved by ovarian grafts in 

 which the follicle cells have 

 degenerated, and of the possible 

 secretory elements only the inter- 

 stitial cells remain. The study of the distribution and comparative 

 physiology of the interstitial cells is still, however, very imperfect, 

 and in some animals these elements have not been discovered, at 

 any rate, in the ovaries of the adult. It is not unlikely that 

 there is considerable variation among the different species of 

 mammals in regard to the development and functional importance 

 of the interstitial cells, and it is possible that they are potenti- 

 ally equivalent to the follicular epithelial cells, since certain 



Fi 



66. — Transverse section 

 through uterus of rat after 

 ovariotomy, showing degen- 

 erative changes. ((V. Fig. 20.) 

 (From Marshall and Jolly.) 



