77>S HANDBOOK OF PHYSIOLOGY. 



Relation of Menstruation to the Discharge of Ova. The human female 

 is subject to the same law as the females of other mammiferous animals; 

 her ova are matured and discharged from the ovary independent of sexual 

 union. This maturation and discharge occur, moreover, periodically at 

 or about the epochs of menstruation. 



The evidence of the periodical discharge of ova at the menstrual 

 periods is that in most cases in which signs of menstruation have been 

 found in the uterus, follicles in a state of maturity or of rupture have 

 been seen in the ovary; and although conception is not confined to the 

 periods of menstruation, yet it is more likely to occur about a menstrual 

 epoch than at other times. 



The exact relation between the discharge of ova and menstruation is 

 not very clear. It was formerly believed that the monthly flux was the 

 result of a congestion of the uterus arising from the enlargement and 

 rupture of a Graafian follicle ; but though a Graafian follicle is, as a 

 rule, ruptured at each menstrual epoch, yet several instances are recorded 

 in which menstruation has occurred where no Graafian follicle can have 

 been ruptured, and on the other hand cases are known where ova have 

 been discharged in amenorrhaeic women. It must therefore be admitted 

 that menstruation is not dependent on the maturation and discharge of 

 ova. 



It was, moreover, formerly understood that ova were discharged 

 toward the close or soon after the cessation of a menstrual flow. Obser- 

 vations made after death, and facts obtained by clinical investigation, 

 however, do not support this view. Rupture of a Graafian follicle does 

 not happen on the same day of the monthly period in all women. It 

 may occur toward the close or soon after the cessation of a flow ; but only 

 in a small minority of the subjects examined after death was this the 

 case. On the other hand, in almost all such subjects of which there is 

 record, rupture of the follicle appears to have taken place before the 

 commencement of the catamenial flow. Moreover, the custom of the 

 Jews a prolific race, to whom by the Levitical law sexual intercourse 

 during the week following menstruation was forbidden militates 

 strongly in favor of the view that conception usually occurs before and 

 not soon after a menstrual epoch, and necessarily, therefore, for the view 

 that ova are usually discharged before the catamenial flow. This, to- 

 gether with the anatomical condition of the uterus just before the 

 catamenia, seems to indicate that the ovum fertilized is that which is 

 discharged in connection with the first absent, and not that with the 

 last present menstruation. 



Though menstruation does not appear to depend upon the discharge 

 of ova, yet the presence of the ovaries seems necessary for the perform- 

 ance of the function; for women do not menstruate when both ovaries 



