580 MENSTRUATION AND PREGNANCY. 



more dense and shrivelled, and is soon converted into a minute, 

 stellate, white, or reddish-white cicatrix. The yellow wall becomes 

 softer and more friable, as is the case with all tissues undergoing 

 fatty degeneration, and shows less distinctly the marking of its 

 convolutions. At the same time its surfaces become confounded 

 with the central coagulum on the one hand, and with the neigh- 

 boring tissues on the other, so that it is no longer possible to separate 

 them fairly from each other. At the end of eight or nine weeks 

 (Fig. 190) the whole body is reduced to the condition of an insignifi- 

 cant, yellowish, cicatrix-like spot, measuring less than a quarter of 

 an inch in its longest diameter, in which the original texture of the 

 corpus luteum can be recognized only by the peculiar folding and 

 coloring of its constituent parts. Subsequently its atrophy goes on 

 in a less active manner, and a period of seven or eight months some- 

 times elapses before its final and complete disappearance. 



The corpus luteum, accordingly, is a formation which results 

 from the filling up and obliteration of a ruptured Graafian follicle. 

 Under ordinary conditions, a corpus luteum is produced at every 

 menstrual period ; and notwithstanding the rapidity with which it 

 retrogrades and becomes atrophied, a new one is always formed 

 before its predecessor has completely disappeared. 



"When, therefore, we examine the ovaries of a healthy female, in 

 whom the menses have recurred with regularity for some time 

 previous to death, several corpora lutea will be met with, in different 

 stages of formation and atrophy. Thus we have found, under such 

 circumstances, four, five, six, and even eight corpora lutea in the 

 ovaries at the same time, perfectly distinguishable by their texture, 

 but very small, and most of them evidently in a state of advanced 

 retrogression. They finally disappear altogether, and the number 

 of those present in the ovary, therefore, no longer corresponds with 

 that of the Graafian follicles which have been ruptured. 



II. CORPUS LUTEUM OP PREGNANCV. 



Since the process above described takes place at every menstrual 

 period, it is independent of impregnation and even of sexual inter- 

 course. The mere presence of a corpus luteum, therefore, is no 

 indication that pregnancy has existed, but only that a Graafian 

 follicle has been ruptured and its contents discharged. We find, 

 nevertheless, that when pregnancy takes place, the appearance of 

 the corpus luteum becomes so much altered as to be readily dis- 



