UDDER-PYOBACILLOSIS 83 



the infected quarter and not infrequently presents similar 

 secondary lesions in other organs. It predisposes to the 

 secondary infections and gangrene, which conditions, espe- 

 cially together, terminate in death. 



In one case the infection confined itself to the cisterns 

 and milk-ducts, to the exclusion of the udder which was 

 nearly free from the infection. This form of the infection 

 induces destruction of the mucous membrane of the milk- 

 ducts with subsequent healing and connective-tissue forma- 

 tion, which closes the lumen of the ducts, with the result 

 that the cisterns present a white vault-like connective-tissue 

 dome without any openings for the milk-ducts. In con- 

 sequence of these alterations the udder shows milk stasis 

 with distended lobuli and tubuli together with a firm con- 

 dition due to sclerotic connective-tissue proliferation. 



Clinical, Symptoms. — The condition is chronic. One 

 or more quarters are affected. The diseased quarters are 

 nodular and swollen in their lower extremities. These 

 nodular foci are hard and painful or soft and then fluctuat- 

 ing. Sometimes one sees a chronic wound or fistula in 

 these foci which presents a stinking secretion indicative of 

 gangrene. The nodular foci develop slowly. 



At first the quantity of milk is only slightly lessened, 

 but later very much diminished. In quarters which have 

 not undergone very marked changes the milk is of almost 

 normal appearance. Later when they have' become more 

 extensively altered the milk shows clumps of pus, since the 

 milk is mixed with pus, and finally it is yellow, thick and 

 purulent and contains free fibrin shreds. In secondary 

 infections the milk can become grayish-red, and in gan- 

 grene it has a foul odor. The odor is often characteristic 

 and it is specific for pyobacillosis. It resembles rotten 

 cabbage. 



Upon microscopical examination of the sediment one 



