MENSTRUAL LIFE 779 



forming a true decidua menstrualis, figure 496, while Moricke and others 

 believe that the mucous membrane remains intact. Leopold believes 

 that red blood corpuscles escape from the congested capillaries and under- 

 mine the superficial epithelium, and that in this way the superficial layer of 

 the mucous membrane is eroded and subsequently regenerated. There 

 is a period of regeneration followed by a period of rest before the next 

 repetition. Minot distributes the variations in time as follows: 



Tumefaction 5 days 



Menstrual discharge 4 days 



Restoration of mucosa 7 days 



Period of rest 12 days 



The menstrual period is often accompanied by profound disturbances in 

 other parts of the body, especially of the vascular and of the nervous systems, 

 and of the nutritive processes. 



CorpusLuteum. Immediately before, as well as subsequent to, the rupture 

 of an ovarian follicle and the escape of its ovum, changes ensue in the interior 

 of the follicle, which result in the production of a yellowish mass, termed a 

 corpus luteum. 



When fully formed, the corpus luteum of mammals is a roundish solid 

 body, of a yellowish or orange color, and composed of a number of lobules, 

 which surround, sometimes a small cavity, but more frequently a small 

 stelliform mass of substance, from which delicate processes pass as septa 

 between the several lobules. The processes gradually change till they 

 nearly fill the cavity of the follicle, and even protrude from the orifice in 

 the external covering of the ovary. Subsequently this orifice closes, but the 

 fleshy growth within still increases during the earlier period of pregnancy, 

 the color of the substance gradually changing to yellow, and its consistency 

 becoming firmer. After the orifice of the follicle has closed, the growth 

 of the yellow substance continues during the first half of pregnancy, till 

 the cavity is reduced to a comparatively small size or is obliterated; in the 

 latter case, merely a white stelliform cicatrix remains in the center of the 

 corpus luteum. 



The first changes of the internal coat of the ovarian follicle in the proc- 

 ess of formation of a corpus luteum seem to occur in every case in which an 

 ovum escapes. If the ovum is impregnated, the growth of the yellow sub- 

 stance continues during nearly the whole period of gestation and forms the 

 large corpus luteum commonly described as a characteristic mark of 

 impregnation. 



The significance of the corpus luteum is found in the belief that it is the 

 portion of the ovary especially concerned in the production of an internal 

 secretion that affects the uterus, especially stimulating it at and before the 

 menstrual period. 



