THE FEMALE GENITAL ORGANS. 353 



The part of the Graafian follicle which remains after the ovum has 

 been released forms a structure known as the corpus luteum, a struc- 

 ture which passes through certain developmental stages and then 

 undergoes degeneration. The regressive metamorphosis is much 

 slower in a corpus luteum whose ovum has been fertilized and is in 

 process of further development than in those whose ova have not been 

 impregnated ; the former is known as the corpus luteum verum, the 

 latter as the corpora lutea spuria. There is as yet difference of opinion 

 as to the mode of development of the corpora lutea, certain observers 

 maintaihing that the cells ofthezona granulosa contribute largely to 

 the development of these structures, while others trace their origin to 

 the cells of the theca interna. In this account we shall follow Sobotta, 

 whose careful observations on the development of the corpora lutea of 

 the mouse and rabbit support strongly the former view. According 

 to this observer, the walls of the Graafian follicle collapse after its rup- 

 ture. The cells of the follicular epithelium, which remains within 

 the collapsed follicle, hypertrophy, the cells attaining many times their 

 original size. As the epithelial cells enlarge, a yellowish pigment 

 known as lutein makes its appearance. The cells are now designated 

 as lutein cells. At the same time the vascular connective tissue of the 

 inner thecal layer penetrates between the hypertrophied epithelial cells 

 in the shape of processes accompanied by leucocytes. 



The structure which thus develops is known as the corpus 

 luteum. On the rupture of the follicle hemorrhages often take 

 place on account of the laceration of the blood-vessels. The re- 

 mains of such hemorrhages are found in the form of hematoidin 

 crystals. 



After a variable time the corpora lutea degenerate ; in this regres- 

 sive metamorphosis the epithelial cells (lutein cells) undergo fatty 

 degeneration, and the connective tissue trabeculae become atrophied. 

 Each corpus luteum is thus changed into a corpus albicans, which in 

 turn is absorbed, and in its place there remains only a connective 

 tissue containing very few fibers. 



Not all of the eggs and follicles reach maturity ; very many 

 are destroyed by a regressive process known as atresia of the fol- 

 licles. This process may begin at any stage, even affecting the 

 primitive ova while still imbedded in the germinal epithelium first 

 attacking the egg itself and later the surrounding follicular epithe- 

 lium, although in both the degenerative process is identical. The 

 germinal vesicle and the nuclei of the follicular cells usually 

 undergo a chromatolytic degeneration, although they sometimes 

 disappear without apparent chromatolysis (direct atrophy), while 

 the cell-bodies are generally subjected to a fatty degeneration or 

 may even undergo what is known among pathologists as an albu- 

 minous degeneration i. e., one characterized by granulation and 

 showing no fat reaction but numerous reactions such as are ob- 

 served where albumin is present. These two forms of metamor- 

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