CORPUS LUTEUM. 



571 



cases where the cavity is obliterated, being proportionately of 

 much larger bulk. The quantity of yellow substance formed 

 is also much less : and, although the deposit increases after the 

 vesicle has burst, yet it does not usually form mammillary 

 growths projecting into the cavity of the vesicle, and never 

 protrudes from the orifice, as is the case in other Mammalia. 

 It maintains the character of a uniform, or nearly uniform, 

 layer, which is thrown into wrinkles, In consequence of the 

 contraction of the external tunic of the vesicle. After the 

 orifice of the vesicle has closed, the growth of the yellow sub- 

 stance continues during the first half of pregnancy, till the 

 cavity is reduced to a comparatively small size, or is obliterated ; 

 in the latter case, nearly a white stelliform cicatrix remains in 

 the centre of the corpus luteum. 



A 



Corpora lutea of different periods. B. Corpus luteum of about the sixth week after 

 impregnation, showing its plicated form at that period. 1. Substance of the ovary. 

 '2. Substance of the corpus luteum. 3. A grayish coagulum in its cavity. After Dr. 

 Paterson. A. Corpus luteum, two days after delivery. D. In the twelfth week after 

 delivery. After Dr. Montgomery. 



An effusion of blood generally takes place into the cavity of 

 the Graah'an vesicle at the time of its rupture, especially in 

 the human subject ; but it has no share in forming the yellow 

 body; it gradually loses its coloring matter, and acquires the 

 character of a mass of fibrin. The serum of the blood some- 

 times remains included within a cavity in the centre of the 

 coagulum, and then the decolorized fibrin forms a membrani- 

 form sac, lining the corpus luteum. At other times the serum 

 is removed, and the fibrin constitutes a solid stelliform mass. 



The yellow substance of which the corpus luteum consists, 

 both in the human subject and in the domestic animals, is a 

 growth from the inner surface of the Graafian vesicle, the re- 

 sult of an increased development of the cells forming the mem- 



