1 66 Veterinary Obstetrics 



fibrosuni simplex; or it may contain a large amount of blood pigment, 

 corpus nigrum. 



Regarding the formation of the yellow body, there is still much difference 

 of opinion. According to Bischoff, Schron, Pfliiger and others, this struc- 

 ture emanates from the inctiibraiia granulosa; von Baer, Kolliker, His, 

 Spiegelberg, Paladino and others consider that it is formed from the tunica 

 interna folliculi. Large spheroidal, polygonal lutein cells occur wiihin the 

 fine fibrous connective tissue stroma of the yellow capsule wall and contain 

 large spherical nuclei, nucleoli, nuclear debris and a finely granular pig- 

 ment ( lutein lipochrome ) permeating the protoplasm. According to Sabotta, 

 in the mouse and rabbit, and to van Beneden and Honor^, in rabbits, these 

 certainly ari.se from the membrana granulosa. The same origin holds good, 

 according to Giacomini, and also Mingazzini, for reptiles and birds. Van 

 der Stricht saw these cells derived, in part, at least, from the granulosa in 

 vesperugo noctula. On the other hand, Clark, Xagel, Biihler and vStcikel 

 are of the opinion that the lutein cells are derived from the cells of the 

 tunica interna folliculi. Zschokke speaks in much the same way of the 

 origin of the yellow body in cattle. He says, " I have for a long time thor- 

 oughly studied and sectioned dozens of ovaries of various animals and am 

 fully convinced that they are derived from the tunica interna."' He found 

 a distinction in the nuclear staining of the granulo.sa cells and those of the 

 tunica ; the first >vas more intense. He further observed that the debris of 

 the granulo.sa could bs differentiated by their form from the growths ema- 

 nating from the tunica interna. It is impossible, however, for one to deter- 

 mine the.se differences in the illustrations in Zschokke's work and to 

 recognize which tissue one is observing because the magnification is too 

 feeble. 



The de-stinv of the yellow bodies is chiefly that they shall occupy the 

 cavity which occurs as a result of the rupture of the follicles. 



According to Bohn, who agrees with Frankel and Cohn, the yellow body 

 consists of a substance secreted by the system, being derived from the blood 

 through the influence of the attachment of the egg to the uterus. 

 Closelv allied to this, also, is the view that the yellow bodies, through 

 these secretions, exert a restraining influence in a certain way upon 

 the ovary and the further development of follicles. In relation to the latter 

 point, perhaps, the simple pressure of the yellow body upon the ovary is 

 partly responsible for the result. Zschokke asserts that, where large cor- 

 pora lutea exist, as a general rule, large, ripe follicles are wanting, while, at 

 the same time, in these animals, estrum is usually absent. Other veteri. 

 narianshave, on the other hand, observed that the existence of yellow bodies 

 does not always prevent the occurrence of estrum. 



In reference to the number of ovarian cyst.s occurring in one 

 animal, we have found in ovaries secured by castration or after 

 slaughter that one gland may be normal while the other has un- 

 dergone cystic degeneration in an extremely variable degree. Very 

 frequently both ovaries suffer, sometimes equally, but far more 



