294 DISEASES OF THE UTERUS 



(d) The retention of a fetus or fetuses which decompose, 

 irritate the mucosa, and, if allowed to remain for a long period , 

 often produce grave symptoms of local inflammation and 

 sapremia. In some cases the uterine mucosa is greatly 

 changed by the infection. The uterus may be converted 

 into a cavity filled with pus (pyometra) . 



(e) Slowness in the involution of the uterus from lack of 

 muscular tone favors the introduction and development of 

 infection. For the same reason individuals weakened from 

 delayed parturition, systemic diseases, etc., are predisposed. 



(/) In bitches and cats that are kept in cold, damp kennels, 

 metritis is occasionally observed, and no doubt results from 

 the general reduction in resistance, and from the weakened 

 condition of the highly sensitive reproductive organs. This 

 favors the development of microorganisms. 



(g) In small animals injuries of various sorts are common, 

 such as being kicked, run over by vehicles, or roughly 

 handled by persons, especially during the latter stages of 

 pregnancy. The uterus may be injured, sometimes torn or 

 lacerated, and inflammation with infection is the common 

 sequel. 



Pathology.— In fatal cases of acute metritis, marked patho- 

 logical changes are observed in the generative tract, and par- 

 ticularly in the uterus. The uterus is dark colored, in some 

 cases almost black, the mucosa showing necrotic areas. In 

 some instances the necrosis extends to the other tissues of 

 the walls of the uterus causing perforations. The walls of 

 the uterus are thickened, edematous; the serous covering 

 is often inflamed as are the adjacent organs and tissues in 

 contact with it. Occasionally abscesses are found in the 

 uterine walls, or in the surrounding tissues. In the virulent 

 cases of metritis there will be found evidences of thrombosis 

 of the bloodvessels of the uterus, leading to embolisms in the 

 vessels in distant parts of the body, producing in some cases 

 pyemic arthritis, etc. The vulva and vagina are swollen and 

 necrotic, and a greenish colored exudate of offensive odor is 

 present. The other organs and tissues will show the usual 

 postmortem lesions of septicemia or pyemia. The blood is 

 dark colored and fails to coagulate. The kidneys and liver 



