MORBID ANATOMY 305 



recovery is usually rapid and complete. In certain other cases, 

 however, complications arise which are not only injurious but 

 may be fatal. Thus the mouth lesions may be accompanied 

 by nasal catarrh or pneumonia. The feet may become very 

 much swollen and the inflammation and suppuration extend 

 to the tendons and bones resulting in the loss of the hoof. 

 Such cases are usually fatal. As a result of the general affec- 

 tion young calves may succumb to a secondary inflammation 

 of the stomach and bowels and older animals may abort or 

 suffer from inflammation of the udder. 



The duration of the disease in uncomplicated cases varies 

 trom ID to 20 days. Where complications occur either with 

 the regular course or as sequelae the duration becomes in- 

 definite. The mortality varies with the severity of the 

 attacks, the age and condition of the animals and the treat- 

 ment. Ordinarily the mortality, is not high excepting in very 

 j-oung animals. 



§231. Morbid anatomy. The tissue changes found at 

 post mortem vary to a marked degree. There is in certain 

 cases hyperaemia and oedma, catarrh of the nares and mucosa 

 of the lungs and dilatation of the heart. There may be fatt}' 

 degeneration and hemorrhagic infarcts in the heart muscle. 

 In other cases there is severe gastro-enteritis vi'ith intestinal 

 hemorrhage. In the stomachs of cattle oval reddish areas 

 which ultimatel}' form ulcers appear. These often become 

 confluent. The involved portion of the mucous membrane 

 becomes thickened. The areas of necrotic tissue in which the 

 ulcers appear become surrounded b)' a reddish line of demar- 

 cation which, in the healing process, forms a cicatrix. 

 The lesions on the mucous membrane rarely extend deeper 

 than the mucosa. Ulcers of a nature similar to those found 

 in the stomach occur in the intestines. On the feet inflam- 

 mations may follow the simple vesicles about the coronet. 

 These may extend deep into the tissues, pass under the hoof 

 and cause it to slough oft", extend into the bone producing 

 necrosis or permanent arthritis. It is stated by some authori- 

 ties that in the mild non-fatal cases the obvious lesions are so 

 slight that frequently they escape notice. In sheep and swine 

 the lesions are more frequently restricted to the feet. 



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