CORPUS LUTEUM <JF PKEGNANCY. 717 



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 

 growth. We have found, under such circumstances, four, five, six, and 

 even eight corpora lutea in the ovaries at the same time, perfectly dis- 

 tinguishable by their texture, though very small, and most of them in 

 a state of advanced retrogression. They finally disappear altogether, 

 and the number of those present in the ovary no longer corresponds 

 with that of the Graafian follicles which have been ruptured. 



II. Corpus Lnteum of Pregnancy. 



The process above described takes place at every menstrual period, 

 independently of impregnation and sexual intercourse. The mere pre- 

 sence 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. It is found, nevertheless, that when pregnancy 

 takes place, the appearance of the corpus luteum becomes so modified as 

 to be readily distinguished from that which follows the ordinary men- 

 strual process. 



The distinction between these two kinds of corpora lutea is not an 

 essential or fundamental difference ; since they both originate in the 

 same way, and are composed of the same structures. It is only a differ- 

 ence in the rapidity and degree of their development. While the corpus 

 luteum of menstruation passes rapidly through its different stages, and 

 is soon reduced to a condition of atroplrv, that of pregnancy continues 

 .its development for a longer time, attains a larger size and firmer 

 organization, and disappears at a much later period. 



This variation in the history of the corpus luteum depends upon the 

 condition of the pregnant uterus. This organ exerts a sympathetic 

 action, during pregnancy, upon many other parts of the system. The 

 stomach becomes irritable, the appetite is capricious, and even the 

 mental faculties and the moral disposition are frequently more or less 

 affected. The ovaries feel the influence of gestation more decidedly 

 than other organs, since they are more closely connected with the uterus 

 in the ordinary performance of their function. The moment that preg- 

 nancy takes place, menstruation is arrested. No more eggs come to 

 maturity, and no more Graafian follicles are ruptured, during the whole 

 period of gestation. It is not surprising that the growth of the corpus 

 luteum should also be modified, by an influence which affects so pro- 

 foundly the system at large, as well as the ovaries in particular. 



During the first three weeks of its formation the growth of the corpus 

 luteum is the same in the impregnated as in the unimpregnated condition. 

 But after that time a difference becomes manifest. Instead of com- 

 mencing a retrograde course during the fourth week, the corpus luteum 

 of pregnancy continues its development. The external wall grows 

 thicker, and its convolutions more abundant. Its color changes, as 



