INFECTIOUS DISEASES 



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resistance of the infected swine. In most instances there will be a 

 rise of temperature from the fifth to the seventh day, and the animals 

 will be visibly sick by the tenth day alter infection. The period of 

 incubation in inoculation experiments varies from four to seven days. 

 Lesions. — Certain lesions have been described by various authors, 

 investigators and practitioners as characteristic of hog cholera, but it 

 has not been definitely determined whether these lesions were due to 

 the filtrable virus or the result of some associated pathogenic agent. 



s.^ 



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Pig. 75. Lungs of hog showing attached lymph-glands. 1, Lymph-glands 

 on pleura adjacent to pericardial sac; 2, right anterior and posterior; 

 bronchial lymph-glands; 3, left bronchial lymph-gland; 4, lymph-gland 

 attached to mediastinal pleura between aorta and left pulmonary lobe; 

 5, lymph-glands on superior surface of aorta peculiar to hogs and 

 taking the place of posterior mediastinal chain of glands in bovines. 

 (Prom Aureggio's "Album Guide.") 



It is possible that hog cholera due to the filtrable virus is a lesionless 

 disease in so far as gross lesions are concerned, excepting those 

 changes that occur as a result of a high antemortem temperature. In 

 many cases carefully autopsied, of the first swine that died of the 

 very acute type of cholera, the only lesions found consisted of pareu- 



