THE FEMALE REPRODUCTIVE ORGANS. 



229 



FIG. 270. 



Portion of well-developed corpus luteum from 

 ovary of rabbit : a, polyhedral cells separated 

 by vascular connective tissue ; b, blood-vessel. 



best developed, the corpus luteum is sharply defined from the sur- 

 rounding stroma, and in appearance recalls somewhat the liver, the 

 polygonal cells being surrounded by capillary blood-vessels. Subse- 

 quent changes lead to retrogression 

 and disappearance of the cells, the 

 entire mass becoming fibrous and 

 cicatricial in character, but remain- 

 ing visible for many months as 

 an obscure, shrunken, irregularly- 

 plicated body in the midst of the 

 cortical tissues. While the forma- 

 tion of a corpus luteum follows the 

 discharge of every mature ovum, 

 when such escape is followed by 

 pregnancy the yellow body be- 

 comes exceptionally large and well 

 developed, presenting a large round 

 mass, 2-3 cm. in diameter, which 

 retains its distinctive character much 

 more tenaciously than the corpus 

 of ordinary menstruation. These differences led to the distinction 

 of the corpus luteum of pregnancy as the true yellow body as 

 contrasted with the ordinary or false ; the former large symmetri- 

 cally-developed body has been regarded as positive proof of preg- 

 nancy, a conclusion, however, which the repeated observation of 

 identical bodies in the ovaries of virgins by no means upholds : the 

 evidence afforded by such corpora lutea should be regarded as cor- 

 roborative rather than as positive. 



The blood-vessels of the ovary enter at the hilus along the 

 attached border. They directly penetrate to the medulla, smaller 

 twigs passing to supply the cortex and the Graafian vesicles. Each 

 of these sacs is surrounded by a net-work of vessels, especially con- 

 spicuous in the larger follicles. The venous vessels within the 

 medulla are of large size, the channels resembling sinuses in their 

 tortuous course and thin walls. 



The lymphatics are numerous within the medulla, while their 

 terminal radicles have been traced within the cortex to the cleft- 

 like spaces within the fibrous tunic of the walls of the larger 

 follicles. 



The nerves of the ovary include medullated and pale fibres, repre- 

 senting both the cerebro-spinal and the sympathetic system. After 

 passing into the interior of the organ, fine twigs enter the cortex, 

 where they have been traced into the envelope of the larger Graafian 

 follicles. 



