320 MICROBIOLOGY 



Life conditions and properties. It is an aerobe and a 

 facultative anaerobe. The most favorable temperature for 

 its development is about 37 C. It grows feebly at 20 C. and 

 ceases to multiply at 43 C. A few cultures 13 have given indol 

 when grown in Dunham's solution. It apparently contains 

 toxins (endotoxins), as immunity has been conferred on sus- 

 ceptible animals by the use of heated cultures. 



Resistance. This organism is destroyed by a tempera- 

 ture of 60 C. for ten minutes. It resists drying for variable 

 lengths of time depending on the amount of protection it has. 

 In drops of bouillon culture it resists drying for from five to 

 six days while in smears from tissues it will live for from 

 20 to 40 days. It is destroyed after ten minutes in a 1% 

 solution of carbolic acid, in .25^ sulphate of copper and 1 to 

 1000 solution of mercuric chloride. 



Pathogenesis. Subcutaneous injections of from 1 to 

 3 cc. rarely produce fatal results in swine. An intravenous 

 inoculation of 5 cc. usually produces a fatal bacteriemia. 

 With smaller doses the "button ulcers," characteristic of hog 

 cholera, have been produced (Welch). By feeding pigs with 

 pure bouillon cultures the intestinal ulcers, typical of hog 

 cholera, have also been obtained (Smith). 



Rabbits inoculated subcutaneously with 0.1 cc. of the 

 bouillon culture die in from 5 to 8 days. The essential lesions 

 consist of necrotic foci (coagulation necrosis) in the liver and 

 a very much enlarged and dark- colored spleen. Guinea pigs 

 are affected similarly to rabbits, but death does not usually 

 occur until from 7 to 12 days. Pure cultures of the bacillus 

 can be obtained from the blood, liver or spleen of the inocu- 

 lated animals. Moore 14 found an organism that could not be 

 differentiated from B. suipestifer in a fatal disease of pigeons 

 in which the symptoms were referable to the nervous system. 

 Smith 15 found a similar organism to be apparently the cause 

 of an infectious abortion in mares. 



13 Moore. Annual Report of the Com. of Agric. of N. Y. State, 

 1897. 



14 Moore. Bulletin No. 3, B. A. I., U. S. Dept. of Agric., 1893, p. 31. 



15 Smith. Ibid., p. 53. 



