DIFFERENTIAL DIAGNOSIS 259 



patches. Lungs normal, excepting the right ventral lobe, which is 

 solid. Bronchi and air cells of this lobe completely occluded by plugs ; 

 surface 1)right red, mottled with yellowish points — the ultimate air cells 

 filled with the cellular exudate. Subpleural ecchymoses over both 

 lungs. From the spleen a liquid and a gelatin culture contained only 

 hog-cholera bacteria. Thej' were very numerous in cover-glass prepar- 

 ations from this organ. 



A rabbit inoculated from the consolidated lung tissue died on the 

 seventh day. At the point of inoculation a pasty mass extends to abdo- 

 men, only subcutis involved. Spleen engorged. Single acini in the 

 liver are completely necrosed, yellowish white. In both organs, hog 

 cholera bacteria. Cultures from spleen pure. (Report on hog cholera, 

 1889). 



The dtiration of the disease varies. In the acute septi- 

 cemic type it ma\' not be more than a few hours or a day at the 

 longest. In the chronic form it lasts from one to two weeks, 

 sometimes longer. 



The pfognosis'is noi good. Berry states that recoveries 

 are not rare. Although there are outbreaks where the mortality- 

 reaches from Soto 100 per cent, there are others of a milder 

 type where the fatalities do not exceed 50 per cent. 



§ 185. Differential diagnosis. Hog cholera is to be 

 differentiated from a great variety of dietary disorders and 

 poisoning from alkalies and possibly from other chemicals 

 which may get into their food. * Powdered soap has been 

 found to produce, when given in sufficient quantities, a series 

 of symptoms quite similar to those of hog cholera. In addi- 

 tion to the many as yet etiologically undetermined disorders 

 often producing a high mortality and popularly called hog 

 cholera, infectious pneumonia or swine plague and tuberculosis 

 are to be distinguished. 



It sometimes happens that swine when kept under good 

 hygienic conditions suffer from disorders which in their symp- 

 toms resemble hog cholera, but anatomically the lesions are 

 varied and irregular. A few such enzootics have been studied. 

 A few have been described. In one instance B. coli communis 

 seemed to stand in a casual relation to the trouble. Recently 

 the writer has studied two similar enzootics where several 



