332 AGRICULTURAL BACTERIOLOGY 



portions of the lung tissue may be consolidated instead of 

 being soft and filled with air. The surface of the heart 

 may show the red blotches. In the acute cases the inner 

 lining of the large intestine is frequently found to be blood- 

 stained, and the feces may be bloody. In the more chronic 

 cases the most characteristic lesions of the disease are found 

 in the large -intestine, the so-called button ulcers, which 

 are rolind, hard, and yellowish with a dark center. They 

 are distinctly raised above the surrounding healthy surface 

 of the intestine. In size they vary from a small point to 

 the size of a twenty-five cent piece. The finding of such 

 ulcers is to be considered as a positive indication of hog 

 cholera, and it is the only lesion that can be regarded as 

 absolutely diagnostic. 



The lymph-glands in various parts of the carcass are 

 found upon section to be enlarged and reddened. 



A number of causes may produce symptoms that may be 

 mistaken for cholera, Pneumonia due to exposure, dust, 

 or lung-worms is sometimes confounded with cholera. Im- 

 proper feeding may cause intestinal disturbances. Slops 

 containing alkalies, such as soap powders, are often a 

 source of trouble to garbage-fed hogs. 



Prevention. Since but little can be done to cure the 

 disease after it has made its appearance in the individual 

 animal, the farmer must direct his efforts to the prevention 

 of the disease. It should be remembered that the organism 

 is eliminated from the body of the affected animal in the 

 urine and feces, and that it is present in all the tissues of 

 the body. An animal that has recovered from the disease 

 may still harbor the organisms in its body and eliminate 

 them. With these facts in mind, the farmer can outline 

 his plan for the protection of his herd. No animal should 

 be purchased from a herd in which cholera has been present 

 during the previous year, nor from a herd that has been 



