PUEKPERAL INFECTION 345 



marrow tissue. In either case arthritis may be serous or 

 purulent. 



Etiology. — The source of the infection is the uterus. The 

 circulation carries the low organism as emboli through the 

 veins to the right heart, then through the pulmonary circula- 

 tion and systemic circulation into the capillaries of the bone 

 marrow. That osteomyelitis may follow intravenous infections 

 of the micrococci, without traumatism otherwise, Bodet's and 

 Lexer's experiments show. 



The infectious agents, same as in polyarthritis, due to in- 

 fection of the navel, are carried by bits of thrombi into the 

 circulation, where they float along until they are arrested in 

 parts where the current is slow and the passage too narrow, 

 now exerting their evil influence (Vogel). 



During the first few days following parturition the uterus 

 is an excellent medium for the development of low organisms ; 

 especially when parts of the placentae have remained and 

 decompose. How far these low organisms or their poisonous 

 products are concerned in the production of polyarthritis is not 

 yet decided. Vogel is of the opinion that those parts devoid of 

 epithelium are the real source through which infection takes 

 place. He also remarks that he was struck by the fact that he 

 usually received a positive reply to the question whether a 

 hemorrhage occurred at the time the foetal envelopes were ex- 

 pelled or whether bloody streaks were observed in the dis- 

 charge. He therefore believes that most cases of puerperal 

 arthritis depend on slight wounds. Strebel thinks that this 

 arthritis is due to the resorption from the uterine cavity of 

 putrid, septic, poisonous materials formed after parturition. 



Polyarthritis is often seen in cows where the expulsion of 

 the afterbirth is retarded, but also in cows apparently under- 

 going a normal process of involution. Another disease due to 

 the same cause, often observed with puerperal arthritis, is 

 mastitis of one half or quarter of the udder. Polyarthritis 

 may also be a symptom of pyaemia. 



Symptoms. — A few days after birth, usually on the sixth or 

 eighth day, the cow walks stiffly. When in the stable the 



