52 Diseases of the Genital Organs 



fails, menstruation. The cow is probably representative for 

 mammalia in general. 



5. The Corpus Luteum of Estrum 



Ovulation leaves behind a crater having the same diame- 

 ter as the ovisac which ruptured. Into this crater, physio- 

 logically, a small amount of blood escapes at once and quickly 

 clots. The walls of the crater rapidly approach each other 

 and within a few hours there remains a small, deep cavity, 

 about one-eighth to three-sixteenths of an inch, filled with a 

 blood clot. Ovulation has necessarily caused a lesion, com- 

 parable in some respects to a wound, in which ordinarily the 

 wound cavity is to a greater or less extent filled with coagu- 

 lated blood, and like the wound in the body covering, the 

 lesion offers an open avenue for invasion by any bacteria 

 existing in the peritoneal cavity or within the oviduct. Such 

 infection frequently interrupts the orderly physiologic pro- 

 cesses and leads to a variety of pathologic lesions. 



Soon after the rupture of the ovisac and discharge of the 

 ovum, there is elaborated from the walls of the crater a 

 distinctive tissue designated the corpus luteum (yellow 

 body) because its prevailing color in pregnant animals is 

 yellow. The corpus luteum consists of a network 

 of capillaries, some connective tissue, and essentially of 

 special lutein cells emanating from the membrana granu- 

 losa and theca interna of the ovisac. The method of growth 

 causes the corpus luteum to repeat at first the form of the 

 crater from the sides of which it originates. Originally it 

 is a cup-shaped structure opening upon the surface and 

 filled in its center by the small blood coagulum which formed 

 in the crater of the ruptured ovisac immediately after ovu- 

 lation. The corpus luteum pushes its way out somewhat 

 through the rupture in the ovarian tunic and projects (in 

 the cow) somewhat above the ovarian surface as a cylin- 

 drical or conical mass of granulations, one-eighth to one- 

 half inch in diameter. The cavity in the center of the cor- 

 pus luteum of the cow is gradually eliminated by the growth 

 of the lutein tissue and at the same time the epithelium of 



