336 AGRICULTUEAL AND INDU8TEIAL BACTEEIOLOGY 



lorum is the cause of the so-called white diarrhea of chicks. 

 Bacterium cholerce-suis has been found frequently associ- 

 ated with hog cholera but is evidently not the cause of the 

 disease, in most cases at least. The following key will 

 differentiate the species.^ 



Bacterium choler^-suis 



Synonyms. — Bacillus suipestiferj Bacillus cholerce-suis, 

 Bacillus salmoni. 



This organism was first described in 1885 by Salmon and 

 Smith as the probable cause of the disease named by them 

 swine plague. A revision of terminology with reference to 

 the swine diseases a little later caused them to describe this 

 as the cause of the hog cholera. It was isolated from a large 

 number of hogs affected with this disease. Much work was 

 done with it in the next two decades in an attempt to 

 produce vaccine and sera for use in treatment or prevention 

 of the disease, hog cholera. In general these proved 

 unsuccessful. It was not until De Schweinitz and Dorset in 

 1904 studied an outbreak of hog cholera in which they were 

 unable to isolate this organism that the causal relationship 



'Key to the Principal Species op the Intermediate Subgroup op 



THE Genus Bacterium 

 A. Producing gas from mannitol. 



1. Producing gas from xylose. 



a. Lead acetate medium not blackened. Arabinose and 

 dulcitol fermented but slowly if at all. 



1. Bacterium cholerm-suis. 



fc. Lead acetate medium blackened. Arabinose and dulcitol 

 fermented promptly. 



(1) Inosite not fermented. 



2. Bacterium enteritidis. 



(2) Inosite fermented. 



3. Bacterium schottmiilleri, 



2. Not producing gas from xylose. 



o. Nonmotile. 



4. Bacterium pullorum 



b. Motile. 



5. Bacterium paratyphi. 

 JB. Not producing gas from mannitol. 



6. Bacterium morgani. 



