CHAPTEE VI. 



THE CORPUS LUTBUM, AND ITS CONNECTION 

 WITH MENSTRUATION AND PREGNANCY. 



AFTER the rupture of the Graafian follicle at the menstrual period, a 

 bloody cavity is left in the ovary, which is subsequently obliterated by 

 a kind of granulating process, somewhat similar to the healing of an 

 abscess. The office of the Graafian follicle is to provide for the forma- 

 tion and growth of the egg within the ovary. After the ripening and 

 discharge of the egg, the Graafian follicle has no longer any function to 

 perform. It then only remains for it to pass through a process of 

 obliteration, as an organ- which has become obsolete. While undergoing 

 this process, the Graafian follicle is at one time converted into a pecu- 

 liar, solid, spheroidal body, called the corpus luteum; a name derived 

 from the yellow color which it acquires at a certain period of its forma- 

 tion. 



In different species of mammalians, the corpus luteum is characterized 

 by certain peculiarities of size, color, rapidity of growth, and disappear- 

 ance, which are distinctive for each particular kind of animal ; although 

 . the general process of its formation and atrophy is the same in all. In 

 the human female it is marked by a moderately large size, a brilliant 

 yellow hue at a certain period of its development, and the presence of 

 blood in its central cavity, distinguishable by its color for two or three 

 weeks after the rupture of the follicle. The details of its growth and 

 retrocession, which follow a certain regular course during the normal 

 recurrence of the menstrual periods, are modified to an appreciable 

 degree by the occurrence of pregnancy. In the first instance, it is 

 known as the corpus luteum of menstruation; in the second as the 

 corpus luteum of pregnancy. 



I. Corpus Luteum of Menstruation. 



At each menstrual epoch, in the human female, a Graafian follicle 

 swells, protrudes from the surface of the ovary, ruptures, and discharges 

 its mature egg. At the moment of rupture, or immediately afterward, 

 a somewhat abundant hemorrhage takes place from the follicle, and 

 its cavity is filled with blood. This blood coagulates soon after its 

 exudation, as it would if extravasated elsewhere, and the coagulum 

 is retained in the interior of the Graafian follicle. The opening by which 

 the egg makes its escape is usually a minute rounded perforation, often 

 not more than one millimetre in diameter. A small probe, introduced 



