Salpingitis 429 



Cystic degeneration of the corpus luteum has already 

 been discussed under "The Diseases of the Ovary." It is 

 not certain that cystic degeneration of the corpus luteum 

 occurs, except with salpingitis, although it cannot be proven 

 that salpingitis is the sole cause. It appears, however, that 

 salpingitis is at least the predominant cause. When the 

 ovisac is about to rupture, it is believed that the pavilion of 

 the tube invests it, with the ostium abdominale in proximity 

 to the ovisac. When ovulation occurs, infection may ap- 

 parently escape from the oviduct, invade the crater left be- 

 hind by the rupture, and set up disease, which eventually 

 brings about the destruction of the yellow body. The de- 

 struction of the corpus luteum by cystic degeneration does 

 not cause the sterility, but the infection which exists in the 

 oviduct causes alike the sterility and the cystic degeneration 

 of the corpus luteum. It follows, therefore, .that cystic de- 

 generation of the corpus luteum may occur in spite of con- 

 ception : that is, spermatozoa may be able to live in the in- 

 fected tube and fertilize the ovum, which may be able to 

 pass through the infected oviduct, reach the uterine cavity, 

 and develop. As a rule, however, cystic degeneration 

 of the corpus luteum does not occur in pregnancy. 

 From my abattoir investigations, I would estimate that 

 not more than one or two per cent, of corpora lutea 

 of pregnancy suffer from cystic degeneration. Perhaps 

 the facts would be more clearly expressed by stating 

 that, when the oviduct is so virulently and abundantly in- 

 fected that the infection will escape from the tube and in- 

 vade the freshly ruptured ovisac, the spermatozoa, and the 

 non-fertilized or fertilized ovum will probably be destroyed. 

 Sometimes, however, the spermatozoon and ovum run the 

 gauntlet of the infected tube although the crater of the ovi- 

 sac is invaded. Then follows, at least in some cases, cystic 

 destruction of the corpus luteum of pregnancy, with recur- 

 rence of estrum in the pregnant animal. The cystic degen- 

 eration of the corpus luteum interrupts more or less seri- 

 ously the estrual cycle. Sometimes the estrual period will 

 return within seven to fifteen days ; sometimes the cycle may 



