30 HOG CHOLERA 



ent, the posterior border of the diaphragmatic lobe 

 as well. The solidified portions may be red but 

 are often rather light in color, macroscopically 

 resembling the surface of a salivary gland. There 

 is a marked tendency for necrosis to develop 

 from numerous foci, and multiple abscesses occur, 

 appearing as slightly elevated yellow areas dotted 

 over the surface of the pneumonic lung. Pleuritis 

 is somewhat constant, and a high degree of em- 

 physema appears in the dorsal nonpneumonic por- 

 tion, giving it a pale white color as compared to 

 the normal pink. Often there is distinct evidence 

 that as a final cause of death an acute pneumonia 

 is superimposed over a more chronic type, in 

 which cases all parts of the lungs are pneumonic, 

 while the lesions in the dorsal and posterior por- 

 tions are of more recent origin. 



B. necrophorus is another organism that some- 

 times complicates hog cholera. Although subject 

 to wide variations in form, it usually appears as a 

 long, slender, nonmotile rod. It is a strict anaer- 

 obe, it stains with the ordinary aniline .dyes, and 

 is Gram negative. Evidently it is quite widely 

 distributed in nature, for it appears in numerous 

 necrotic lesions in practically all domesticated ani- 

 mals. It is regarded as a normal inhabitant of the 

 intestinal tract in swine, and it exists in soil con- 

 taminated with manure. It is the exciting cause 

 of calf diphtheria, lip and leg ulceration in sheep, 



