50 THE CORPUS LUTEUM. 



Thirdly, although in women, sexual connexion is not confined to these 

 periods, yet it is an old observation, confirmed by the experience of some 

 eminent modern accoucheurs, and by the results of inquiries instituted by 

 M. Raciborski, that conception is more likely to occur within a few days 

 after the cessation of the menstrual flux than at other times : and hence 

 the distinguished obstetrician, Naegeli, is accustomed to reckon the dura- 

 tion of pregnancy at nine months and eight days from the last menstrual 

 period, and in normal cases has, he says, never been wrong. These are 

 strong grounds for believing that the discharge of ova is confined to the 

 periods of menstruation. 



The number of facts at present collected are insufficient to establish it 

 as a law that an ovum is discharged from the ovary of the human female 

 at every normally developed period of menstruation. Yet it must be observed 

 that although the diseases causing death must, in the majority of instances, 

 disturb the function of the ovaries, and prevent the extrusion of the ovum, 

 yet to each of those inquirers who have been on the watch for such cases, 

 several instances of ruptured follicles in menstruating woman have occurred 

 within a short space of time. And the fact that the ovaries of the human 

 female become turgid and vascular at the menstrual periods, as those of 

 animals do at the time of heat, strongly favours the opinion that the gene- 

 rative system of the human female is subject to the almost universal law 

 of the periodical discharge of ova.* 



The discharge of an ovum always gives rise to the formation of a corpus 

 luteum. 



This is the statement of M. Bischoff. But most of the recent writers 



* Dr. Ritchie, however, adduces some observations, which, if confirmed, would shew 

 that the operation of this law is much modified in the human subject. He states that 

 ovarian follicles are found ruptured even before the commencement of menstruation, as well as 

 during its subsequent suspension, whether this arises from normal causes or a disordered state 

 of the system. He admits, however, that the full development of the ova and the Graafian 

 follicles is generally, though not necessarily, associated with menstruation, (Contributions, 

 second series, part ix. Med. Gaz. vol. xxxvi. p. 811,) and that only those of follicles which 

 burst at or about the time of menstruation, undergo further organic development, or changes 

 in their coats, (p. 982.) The openings, too, in the peritoneum over the ovarian follicles of 

 the amenorrhagic or non-menstruating female, Dr. Ritchie states, are punctiform, while in 

 the menstruating female they are uniformly linear or crucial and of much larger size. This 

 difference he ascribes to the greater activity of the ovaries in menstruating, than in other 

 women, (p. 325.) Dj. Ritchie also maintains that menstruation may occur several succes- 

 sive times without the evolution of an ovum ; founding this statement on his examination 

 of the ovaries of women who had menstruated regularly, (p. 940.) But this, it is obvious, 

 is no formidable objection to the theory that the extrusion of ova is connected with the 

 function of menstruation. For the organic excitement and vascular turgescence of the 

 ovaries, on which menstruation certainly depends, may have been sufficient to determine the 

 occurrence of the latter function, but yet, from some cause or other, inadequate to produce 

 the rupture of an ovarian follicle. In some cases, too, it may, and in all probability, does 

 happen, that ova are matured, and the follicles prepared for bursting, yet the discharge of 

 the ova is prevented by a thickened state of the peritoneal covering of the ovary. 



