Persistent Corpus Luteum 



421 



the roof of the vagina, and dislodge the corpus luteum care- 

 fully and completely. When this has been done, the com- 

 pression should be continued upon the ovary for some min- 

 utes, in order to anticipate any possibility of serious hemor- 

 rhage. Ordinarily estrum occurs within three to five days, 

 when, if other conditions are favorable, breeding may occur. 



8. Persistent Corpus Luteum 



Writers upon the subject of sterility describe very fre- 

 quently a persistent corpus luteum. In the preceding sec- 



Fig. 136 — Cystic Degeneration of Corpus Luteum. 



Left figure, CL, corpus luteum of pregnancy for comparison ; ri^ht figure 



with 2 cysts, C, C, the left cyst having remnant of lutein tissue at CL. 



tion, it has been mentioned that, when the corpus luteum is 

 hemorrhagic or when it undergoes cystic degeneration, its 

 destruction and absorption may be indefinitely delayed. In 

 the following paragraph (9) the question of the central or 

 imbedded corpus luteum will be discussed. There is, how- 

 ever, a third group of corpora lutea which, although appar- 

 ently sound and normal in volume, tend to remain indefi- 

 nitely without undergoing either atrophy or degeneration. 

 The only symptom of such condition is that the animal has 

 not been bred or has not conceived and does not come in 

 estrum. Upon examination, the genital tract in general may 



