ANATOMY AND HISTOLOGY OF THE OVARIES 545 



Two chief varieties of corpus luteum are recognized ; the corpus luteum 

 spurium, which, in the absence of pregnancy, begins to atrophy about two 

 weeks after ovulation; and the corpus luteum verum (of pregnancy), 

 which remains fully developed for several months. 



On section, a striking, perhaps superficial, resemblance to the supra- 

 renal gland is noted, a fact which first led Born to suspect that they possess 

 the power of producing an internal secretion. It may be seen (Fig. 5) 

 that the cells in the outer portion are roughly disposed in columns, simulat- 

 ing those of the suprerenal cortex, between which run the larger blood 



Fig. 5. Section of human corpus luteum (c), with attached Graafian follicle (f) 

 ( magnification 5 ) . 



vessels, lymphatics, and nerve fibers that have penetrated into the tissue 

 from the ovarian substance. Quite recently a group of French anatomists 

 have revived this idea of similarity by emphasizing the fact that the cor- 

 pora lutea and the suprarenal cortex are both developed from closely 

 related anlagen, and that they contain apparently identical lipoid material. 



Origin, Development and Retrogression 



Source of Corpora Lutea. The corpora lutea are formed from the 

 Graafian follicles after the liberation of their ova, in part at least, by the 

 proliferation of the cells of the zona gramilosa and the penetration of 

 connective tissue, blood vessels, nerves, and lymphatics. There is some 

 difference of opinion as to whether the true lutein cells, which form the 

 characteristic yellow pigment, are derived from the granulosa itself, or 

 from the theca interna, or from both. The inadequacy of our knowledge 



