602 Hog-cholera 



tine (Fig. 175), the collapse, and the occasional broncho- 

 pneumonic changes in the lung. Pulmonary changes, 

 however, are more characteristic of swine-plague (q. v.). 

 The kidneys are nearly always affected, containing 



Fig. 176. Bacillus of hog-cholera, showing flagella. 



numerous petechial hemorrhages, and the urine containing 

 albumin and tube-casts. 



The bacillus is disappointing in its effects upon hogs. When 

 they are subcutaneously or intravenously introduced or fed 

 to such animals they sometimes fail to become diseased, 

 sometimes show fever and depression, but rarely die. Ani- 

 mals thus made ill do not communicate the disease to others. 

 It seems, therefore, as if there was a radical difference be- 

 tween the natural and experimental hog cholera, and much 

 doubt is thrown upon the specificity of the micro-organism. 

 In the recent work of de Schweinitz and Dorset,* Nilesf 

 and Dorset, Bolton and McBryde,J it has been shown that 

 there is a form of hog-cholera that can be transmitted by 

 subcutaneous injection of the filtered and bacteria-free blood- 

 serum of hogs ill of the disease, and that immunity could be 



* Circular No. 41 of the Bureau of Animal Industry of the U. S. 

 Dept. of Agriculture, 1903. 



f Circular No. 43. 



J Bull. No. 72, Bureau of Animal Industry, U. S. Dept. of Agricul- 

 ture, 1905. 



