Bacilli Resembling the Typhoid Bacillus 679 



This observation was received with approval by those who 

 had any experience with the effect of hog-cholera bacilli 

 upon hogs, all of whom must have observed that though 

 infection with the bacilli occasionally caused the death of an 

 animal, the dead animal usually did not show the typical 

 lesions of the disease and never infected other animals 

 with which it was kept. The papers upon the subject by 

 Dorset, Bolton, and McBryde* and by Dorset, McBryde, and 

 Nilesf are worth reading. 



These investigations entirely change our ideas of the im- 

 portance of the hog-cholera bacillus, whose relation to the 

 disease now comes to resemble that of Bacillus icteroides 

 to yellow fever. 



The bacillus of hog-cholera was first found by Salmon and 

 Smith,| but was for a long time confused with the bacillus 

 of "swine-plague," which it closely resembles, and in associa- 

 tion with which it frequently occurs. It is a member of 

 the group of bacteria to which Bacillus icteroides and B. 

 typhi murium belong. The organism was secured by 

 Smith from the spleens of more than 500 hogs. It occurs 

 in the blood and in all the organs, and has also been culti- 

 vated from the urine. 



Morphology. The organisms appear as short rods with 

 rounded ends, 1.2 to 1.5 ^ long and 0.6 to 0.7 ^ in breadth. 

 They are actively motile and possess longflagella (peritrichia) , 

 easily demonstrable by the usual methods of staining. No 

 spore production has been observed. In general the bacillus 

 resembles that of typhoid fever. It stains readily by the 

 ordinary methods, but not by Gram's method. 



Cultivation. No trouble is experienced in cultivating 

 the bacilli, which grow well in all the media under aerobic 

 and anaerobic conditions. 



Colonies. Upon gelatin plates the colonies become 

 visible in from twenty-four to forty-eight hours, the deeper 

 ones appearing spheric with sharply defined borders. The 

 surfaces are brown by reflected light, and without markings. 



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

 ture, Washington, D. C., 1905. 



t "Bull. No. 102 of Bureau of Animal Industry," U. S. Dept. Agri- 

 culture, Washington, D. C., Jan. 18, 1908. 



t" Reports of the Bureau of Animal Industry," 1885-91; and 

 "Centralbl. f. Bakt. u. Parasitenk.," Bd. ix, Nos. 8, 9, and 10, March 

 2, 1891. 



