BTIOLOGY 



249 



widely disseminated throughout the central part of the United 

 States. It exists, however, to a certain degree in every state 

 in the Union and in Canada. It has long been known in 

 Great Britain. It prevails to a greater or less extent on the 

 continent of Europe. The confusion that has arisen in the use 

 of the terms swine plague and hog cholera renders it difficult 

 to determine, from the brief description given in a number of 

 reports, the nature of the disease in question. 



§ 182. Etiology. The specific disease, here described as 

 hog cholera, is caused by Bacillus cholerae suis.'^ A brief des- 

 cription of its morphology, physiological properties and patho- 

 genesis are appended. 









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Fig. 59. A photograph of the bacillus of hog cholera with the flagella 

 stained. X about 1000 diameters. 



*Moore described a bacterium found in a pig, from which the swine 

 plague organism was also obtained, that possessed the cultural and 

 pathogenic properties of the hog-cholera bacillus. More recently, 

 Smith has described a similar organism, which was isolated by Burrell 

 in Illinois. 



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