LUNG PLAGUE OF CATTLE 373 



areas of congestion lying beside those showing red or gray 

 hepatization or even necrosis. As a result the cut surface 

 presents a distinctly variegated, marbled appearance very 

 characteristic of the disease. The bloodvessels are distended 

 and thrombosed. The corresponding lymph glands are 

 swollen and edematous. 



In chronic cases the proliferated interlobular connective 

 tissue is almost white in color and very firm. The portions of 

 the lung they surround are necrotic and sometimes calcified. 

 In such cases a thick connective-tissue capsule may inclose 

 areas from the size of a walnut to a grapefruit— so-called 

 - sequesters. A zone of reactive inflammation surrounds the 

 capsule. The pleura shows serofibrinous pleuritis which can 

 involve the pericardium. ' Rarely there is serofibrinous peri- 

 tonitis, especially in the region of the diaphragm and liver. 

 In calves arthritis of individual joints and a gelatinous infil- 

 tration of the subcutis (dewlap, chest) may exist. 



Symptoms. — The period of incubation is from one to four 

 weeks. In many instances it appears shorter, the early symp- 

 toms (temperature) being obscure and passing unobserved. 

 In very hot weather the attack is often more sudden and 

 severe than in the cold season. 



The symptoms are very varied. From a clinical standpoint 

 usually two stages can be recognized. During the first stage 

 (so-called occult stage) a peculiar short, weak, painful cough 

 is heard, especially after drinking or eating' or when driven up 

 or out of the barn. The patients are languid, show capricious 

 appetite, suppressed rumination and stand with back arched, 

 head down and ears pendent. Driving the animal induces 

 dyspnea. The temperature is usually somewhat elevated (one 

 or two degrees). This condition may exist from two to four 

 weeks, and lead to recovery or the symptoms may become 

 more pronounced. Second stage: The temperature ascends 

 to 104° to 108° F., and severe dyspnea develops, the mouth is 

 held open, tongue protrudes, and each expiration is accom- 

 panied by a loud moan. The patient usually stands with its 

 neck extended and elbows.turned out ; if it lies down it does so on 

 the affected side. There is usually complete loss of appetite, 

 suppressed rumination and cessation of milk flow. There is 



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