BLACK-LEG 289 



and dry, and on palpation marked crepitation is noted. When 

 the tumors are incised, a bloody, foamy fluid of a peculiar 

 sweetish, fetid odor is discharged. The periphery and en- 

 vironment of the swelling are edematous. The lymph glands 

 are swollen, and may be felt under the skin as firm nodes 

 at times, the size of a goose egg. As the swellings enlarge 

 the symptoms become more pronounced, the patient shows 

 marked dyspnea, is unable to rise, muscular tremors and even 

 violent convulsions occur, the temperature rapidly falls, and 

 death follows. 



Course. — The course is rapid and fatal. Most patients die 

 in from twelve to forty-eight hours. Isolated cases may 

 linger several days (mild invasion, high resistance), then die, 

 or in rare instances recover. 



Diagnosis. — Black-leg is a disease easily diagnosed, pro- 

 vided the typical swellings are in evidence. As a rule the 

 owner or ranchman recognizes it without professional aid. If 

 the characteristic emphysematous enlargements are absent, 

 however, as is common in the first cases of some out- 

 breaks, a diagnosis intra vitam is very difficult. Black-leg 

 may be confused with malignant edema and anthrax (see 

 these). 



Necropsy. — The cadaver is greatly bloated and swollen, 

 especially about the tumors. When the swellings are cut into, 

 a foamy, dark, fluid flows out. The affected muscle is of a 

 dirty brown to blackish color, very friable, and often smells 

 like rancid butter. The blood is dark colored but coagulates 

 readily. In the serous cavities blood-stained fluid is found. 

 The lymph glands corresponding to the tumors are swollen 

 and blood-shot. The spleen is usually normal. The charac- 

 teristic postmortem lesions are : normal blood, normal spleen, 

 and emphysematous swellings. 



Prognosis. — In young cattle fully 98 per cent. die. In older 

 individuals a few recover. 



Treatment. — A medicinal treatment is useless. Surgical 

 intervention as recommended in malignant edema is rarely 

 advisable except in very valuable individuals. It is further- 

 more a menace, as the discharge from the incisions spreads 

 the infection. 

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