ETIOLOGY lyr 



cribed in other lands under different titles. While the names 

 assigned may not have been especially happy ones, the trans- 

 fer of swine plague from the intestinal to the lung disease 

 must be considered as a fortunate occurrence and one which 

 tended to simplify and not to confuse. 



Billings, of the Nebraska State Experiment Station, 

 opposed this nomenclature. He not only refused to accept 

 the change and continued to write about hog cholera under 

 the title of swine plague, but he denied the existence of the 

 swine plague, as described in the reports of the Bureau of 

 Animal Industry for 1886 and subsequently, as an indepen- 

 dent disease. The wide dissemination of his publications on 

 this subject has unquestionably been responsible for much of 

 the haziness concerning the distinguishing features of these 

 maladies. 



In 1893, Drs. Welch and Clements read a paper before the 

 International Veterinary Congress in which they gave a very 

 clear history of the nomenclature of these diseases and in 

 which they adhered to the one of the Bureau of Animal 



Industry. 



§133. Geographical distribution. Hog cholera is 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 European 

 continent. The confu.sion which has arisen in the use of the 

 terms swine plague and hog cholera renders 

 it difficult to determine from the brief de- 

 scription in a number of reports the nature 

 of the malady in question. .^ 



§134. Etiology. The specific disease, Sk;^ ^1 



here described as hog cholera, is caused by . 



° . . . Fig. 39. Bacillus 



Bacillus cholerae suis. A brief description of hog cholera both 



of its morphology, physiological properties with and ivithoid 



and pathogenesis are appended. flagella. 



^ 135. A brief description of the bacillus of hog 

 cholera. 



