128 SWINE DISEASES 



injuries produce no bad after effect, but occasionally they 

 provide an avenue of entrance for infection of the peri- 

 toneum and may result in fatal peritonitis. 



Hemorrhage 



Uterine hemorrhage in the sow is not of the same 

 gravity as it is in the larger animals; however, its control 

 is more difficult in the sow than in larger animals because 

 of the small size of the uterus. 



Metritis 



Metritis is not so common in the sow as it is in the 

 larger animals, or even in the sheep and goat. This is 

 probably because of the fact that retention of the pla- 

 centa is not so common in sows as in almost all other 

 animals. The usual cause of metritis is infection, which 

 ordinarily is a sequel to injuries, retained placenta, or 

 dead fetuses. The sow appears to possess considerable 

 resistance to uterine infection, for cases of metritis are 

 relatively rare, and as further evidence of their resistance 

 mummified fetuses are of common occurrence in sows. 



Metritis may be either purulent or septic. 



Purulent Metritis 



Purulent metritis is characterized by hyperemia and 

 tumefaction of the uterine mucous membrane. Later 

 there is desquamation of areas of the mucous membrane 

 and accumulation of quantities of pus in the uterine 

 cavity. . Should the cervix become closed, there may be 

 a marked distention of the uterus with the accumulated 

 pus. The inflammation may extend into and involve 

 the muscular coat of the uterus or even the serous mem- 

 brane. In addition to the inflammatory lesions there 

 may be lacerations and various other injuries. 



Septic Metritis 



Septic metritis is characterized by intensive inflam- 

 mation involving in turn, as the disease progresses, the 

 mucosa, muscularis, and serosa. The uterus usually con- 



