682 EXPERIMENT STATION EECOED. 



immunizing or to the invasion of the bacilli from the intestine when these are 

 not present in the injected blood. The serum of hogs treated with a strain of 

 virus which had never been associated with B. suipestifer yielded hardly any 

 or no agglutinins for B. suijyestifer. 



From some immunizing tests with B. suipestifer it is inferred that it is not 

 essential that an antihog cholera serum intended for simultaneous vaccination 

 should agglutinate B. suipestifer, providing the same virus is used for the 

 vaccination as was employed for preparing the serum. " However, the immu- 

 nity thus acquired, while apparently sufficient to protect against subcutaneous 

 inoculation of small doses of bacilli, seemed to break down under intravenous 

 inoculation of large amounts of bacilli containing blood. ... It may be men- 

 tioned also that most serum hogs which die during treatment (when not due 

 to mechanical overloading of the circulation) show a generalized B. suipestifer 

 infection which is sugge.stive of insufficient preliminary immunization against 

 this bacillus." 



Of the associated bacteria found in the filterable virus of hog cholera, nest to 

 B. suipestifer is the colon bacillus. A coccus which is described as morpho- 

 logically resembling M. catarrhalis was found in the spleen, liver, and blood in 

 several cases of hog cholera. This organism grows feebly upon ordinary media 

 and its cultures were nonpathogenic for guinea pigs. B. pyocyaneus was noted 

 occasionally in the pulmonary lesions of hog cholera, but more frequently in the 

 large local lesions which followed inoculation. B. suisepticus was found veiy 

 infrequently, and in all except one case it was associated with marked pulmonary 

 involvement in pneumonia and i^leurisy. A variety of organisms were noted 

 occasionally in the culture tubes. 



Of the many cultures obtained from organisms in cholera hogs giving a fer- 

 mentation reaction, which was regarded as presumptive evidence of B. suipesti- 

 fer, a number were given a study relative to their fermentative behavior toward 

 various carbohydrates (dextrose, galactose, maltose, and mannit). All of the 

 organisms studied gave the general cultural reactions ascribed to the hog cholera 

 or B. enteritidis subdivision of tlie colon group of bacilli. 



" The one feature in which these strains showed a considerable variation was 

 in the production of indol in Dunham's peptone solution after one week's incu- 

 bation. According to the text-books indol production in peptone solution is not 

 a feature belonging to this species, although it may occasionally occur." 



From the agglutination tests with antiserum it is concluded that " the view 

 which some have entertained, that the bacilli which have been so generally 

 cultivated from the organs of cholera diseased hogs and described as B. 

 suipestifer or B. cholerwsuis really include a variety of organisms presenting 

 on closer study differences in cultural characteristics, is not supported by this 

 investigation where all the strains studied are practically identical in cultural 

 and biologic characters. ... It seems therefore that cultures from the organs 

 of cholera diseased hogs giving the fermentation tube reaction which we have 

 called presumptive evidence of B. suipestifer are probably always this species. 

 It is of interest that this same fermentation tube reaction has occasionally been 

 found in city water tests here but never further investigated. , . . Swine 

 plague as an independent disease has not been met with during this investi- 

 gation." 



Hog cholera in Montana, W. J. Taylor (Montana Sta. Circ. 33 (1913), pp. 

 153-165, figs. 7). — This deals in a popular way with the extent of the hog 

 raising industry and hog cholei-a in Montana. It discusses how hog cholera Is 

 spread, the symptoms and the post-mortem changes in the disease, methods for 

 controlling hog cholera, disposition of dead carca.sses, disinfectants and dis- 

 infection, hog cholera vaccine, and methods of vaccinating against hog cholera. 



