376 THE PHYSIOLOGY OF REPRODUCTION 



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 

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

 hand, it is scarcely conceivable that an ovum could become attached 

 to a uterine 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. 1 Furthermore, 

 it has just been mentioned that the maternal placenta undergoes a 

 partial degeneration in the later stages of embryonic development. 



MHS Lane-Claypon 2 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 SuiTusKi) INTERNAL SECRETION OF THE UTERUS 



Although the bulk of evidence obtained clinically 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 supposition 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 affirmed 

 the belief that the ovarian functions themselves are dependent upon 

 uterine influence. 



Zweifel and Abel, 3 in describing the after-histories of cases of 

 hysterectomy, stated' that, in their experience, when the whole of the 

 uterus was removed, entire atrophy of the ovaries always followed, 

 so that menopause symptoms set in similar to those occurring after 

 ovariotomy. In those cases, however, in which a portion of the 

 uterine mucous" membrane was conserved, menstruation continued 

 and there were no menopause symptoms. Consequently, these 



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

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



2 Lane-Claypon, "On the Origin and Life-History of the interstitial Cells 

 of the Ovary of the Rabbit," Proc. Roy. ,S'oc., B., vol. Ixxvii., 1905. 



3 Zweifel, Deutsche Gesellschaft fiir Gynakologie in Berlin, Zentral. f. 

 <: : imik.. No. 21, 1899. Abel, " Dauererfolge der Zweifelschen Myomektomie," 

 Jr.-/,. f, (,'i/nfii:, vol. Ivii., 1899. 



