522 



COEPUS LUTEUM. 



Corpus luteum. 



by a thin, fibrous layer of stroma. The Graafian vesicle is, there- 

 fore, the parent of the ovum. Periodically, as development is going on, 

 the Graafian vesicle bursts, and the ovum is set free. This effect arises, 

 in part, from the circumstance that, the space between the vesicle and 

 ovum being filled with cells, those near the surface of the ovary disap- 

 pear, and an albuminous liquid, which accumulates below, pushes the 

 ovum up. This extrusion of ova occurs even in childhood. The ovisac, 

 or Graafian vesicle, thus changed into a follicle, is gradually filled up, its 

 walls wrinkling, and red-colored material, arising from the membrana 



granulosa, being deposited in it until it is almost filled. 



This deposit gradually turns yellow, and is eventually com- 

 posed of cells interiorly, and fibres arising therefrom exteriorly. When 

 the deposit is completed, a stellated cicatrix is observed in its midst. 

 The yellow body thus arising passes under the designation of corpus lu- 

 teum. If impregnation does not occur, the yellow substance forms to 

 but a small extent, and after a time disappears. It is relatively more 

 abundant in animals than in women. Attempts have been made to use 

 the indications of the corpus luteum for determining the question of preg- 

 nancy. The following points are presented by Dr. Dalton as offering 

 characteristics by which the corpora lutea of pregnancy and menstruation 

 may be distinguished : " The corpus luteum of pregnancy arrives more 

 slowly at its maximum development, and afterward remains for a long 

 time as a noticeable tumor instead of undergoing rapid atrophy. It re- 

 tains a globular or only slightly flattened form, and gives to the touch a 

 sense of resistance and solidity. It has a more advanced organization 

 than the other kind, and its convoluted wall is much thicker. Its color 

 is not of so decided a yellow, but of a more dusky hue, and if the period 

 of pregnancy is at all advanced, it is not found, like the other, in com- 

 pany with unruptured vesicles in active process of development." 



Fig. 252, corpora lutea of different periods : a, corpus luteum two 



Fig. 252. 



Corpora lutea. 



days after delivery ; I, corpus luteum of about sixth week after impreg- 

 nation, showing its plicated form at that period ; 1, substance of ovary ; 

 2, substance of corpus luteum ; 3, grayish coagulum in its cavity ; d, in 



