712 OVULATION AND MENSTRUATION. 



menstrual epoch than at other times. This fact, established as a matter 

 of observation by practical obstetricians, depends upon the coincidence 

 in time between the occurrence of menstruation and the discharge of the 

 egg. Before its discharge, the egg is immature, and unfit for impregna- 

 tion ; and after the menstrual period has passed, it loses its freshness 

 and vitality. The exajct length of time, preceding and following the 

 menses, during which impregnation is possible, has not been ascer- 

 tained. The spermatozoa, on the one hand, retain their vitality for an 

 unknown period after coition, and the egg for an unknown period after 

 its discharge. Both these occurrences may either precede or follow 

 each other within certain limits, and impregnation may still take place; 

 but the precise extent of these limits is uncertain, and is probably more 

 or less variable in different individuals. 



The above facts indicate the true explanation of certain exceptional 

 cases, in which fertility exists without menstruation. Various authors 

 (Churchill, Reid, Yelpeau) have related instances of fruitful women in 

 whom the menses were scanty and irregular, or even entirely absent. 

 The menstrual flow is only the external accompaniment of a more 

 important process tnking place within. It is habitually scanty in some 

 individuals, and abundant in others. Such variations depend upon the 

 condition of vascular activity of the system at large, or of the uterine 

 organs in particular ; and though the bloody discharge is usually an 

 index of the general aptitude of these organs for impregnation, it is 

 not an absolute or indispensable requisite. Provided a mature egg be 

 discharged from the ovary at the appointed period, menstruation properly 

 speaking exists, and pregnancy is possible. 



The blood which escapes during the menstrual flow is supplied by the 

 uterine mucous membrane. If the cavity of the uterus be examined 

 after death during menstruation, its internal surface is found smeared 

 with a sanguineous fluid, which may be traced through the uterine 

 cervix into the vagina. The Fallopian tubes are sometimes congested, 

 and filled with a similar bloody discharge. The menstrual blood has 

 also been seen to exude from the uterine orifice in cases of procidentia 

 uteri, as well as in the natural condition by examination with the 

 vaginal speculum. It is discharged by a kind of capillary hemorrhage, 

 and, as a general rule, does not form a visible coagulum, owing to its 

 being gradually exuded from many minute points, and mingled with a 

 large quantity of mucus. When poured out more rapidly or in larger 

 quantity than usual, as in menorrhagia, the menstrual blood coagulates 

 in the same manner as that derived from other sources. Its discharge 

 takes place from the whole extent of the mucous membrane of the body 

 of the uterus, and is, at the same time, the consequence and the natural 

 termination of the periodical congestion of the parts. 





