ORGANS OF INTERNAL SECRETION 345 



in the presence of which indifferent stimuh (traumatisms), may 

 produce deciduoniata. 



It has been shown that the uterine mucosa undergoes atrophy 

 after the complete removal of the ovaries, and it seems hardly 

 probable that this process can be arrested by the presence of a 

 fertihsed ovum in the early stages of pregnancy. On the other 

 hand, it is scarcely conceivable that an ovum could become 

 attached to a uterinfe mucous membrane which was in process 

 of degenerating. It would appear, however, that in the latter 

 half or two-thirds of pregnancy, when the uterus has already 

 undergone great hypertrophy, the presence of the ovaries may 

 be dispensed with.^ Furthermore, it has just been mentioned 

 that the maternal placenta undergoes a partial degeneration in 

 the later stages of embryonic development. 



Miss Lane-Claypon ^ has shown that the interstitial cells of 

 the ovarian stroma undergo an increase in size during the period 

 of gestation, but this increase is not so great as that of the 

 luteal cells. Consequently, she suggests that these cells also 

 may produce a secretion of the nature postulated for the cells 

 of the corpus luteum. If this is so, the circumstance that the 

 interstitial cells do not hypertrophy to the same extent as the 

 luteal cells may perhaps be ascribed to the different conditions 

 of mechanical pressure existing in the ovarian stroma. 



The Supposed Internal Secretion of the Uterus 



Although the bulk of evidence obtained chnically points to 

 the conclusion that the uterine functions fall into abeyance 

 after the extirpation of the ovaries, while the relatively few 

 exceptions to this rule are probably to be explained on the sup- 

 position of incomplete removal, some surgeons and gynaecologists 

 have adopted the view that the uterus is capable of functional 

 activity independently of the ovaries. A few writers have even 

 gone further, and have afhrmed tIEe behef that the ovarian 

 functions themselves are dependent upon uterine influence. 



' It has yet to be proved, however, that the further course of development 

 is absolutely normal after ovariotomy in the later part of pregnancy. 



' Lane-Claypon, " On the Origin and Life-History of the Interstitial Cells 

 of the Ovary of the Rabbit," Proc. Roy. Soc, B., vol. Ixxvii., 1905. 



