678 Bacillus Suipestifer 



kill it in from twelve to eighteen hours. Guinea-pigs are 

 more resistant. Subcutaneous injection of dogs produces a 

 hard, painful swelling, which persists for a short time and 

 then disappears without suppuration. It is also infectious 

 for man, a number of epidemics of peculiar pneumonia, char- 

 acterized by the presence of the bacillus in the blood, traceable 

 to diseased parrots, having been reported. 



Differentiation. Bacillus psittacosis can best be differ- 

 entiated from the typhoid and the colon bacilli and others 

 of the same group by its pathogenesis and by the reaction 

 of agglutination. Typhoid immune serum produces some 

 small agglutinations, but a comparison between these and 

 the agglutinations formed by cultures of the typhoid bacillus 

 shows immediately that the micro-organisms are dissimilar. 

 Differentiation is best made out when the prepared hanging- 

 drop specimens of serums and cultures are kept for some 

 hours in an incubating oven. It is not known whether the 

 bacillus is peculiar to the intestines of parrots, invading their 

 tissues when they become ill, or whether it is a purely patho- 

 genic micro-organism found only in psittacosis. 



BACILLUS SUIPESTIFER (SALMON AND SMITH). 



General Characteristics. An actively motile, flagellated, non- 

 sporogenous, non-chromogenic, non-liquefying, aerobic and optionally 

 anaerobic, aerogenic bacillus pathogenic for hogs and other animals. 

 It stains by the ordinary methods, but not by Gram's method. It 

 ferments dextrose, lactose, and sucrose, but does not form indol or 

 coagulate or acidulate milk. 



Hog-cholera, or "pig typhoid," as the English call it, is a 

 common epidemic disease of swine, which at times kills 90 

 per cent, of the infected animals, and thus causes immense 

 losses to breeders. Salmon estimates that the annual losses 

 from this disease in the United States range from $10,000,000 

 to $25,000,000. For years it was thought to be caused by the 

 Bacillus suipestifer, but DeSchweinitz and Dorset* were 

 able to transmit the disease from one hog to another in certain 

 of the body fluids that had been passed through the finest 

 porcelain filters and were shown by inoculation and cultiva- 

 tion to be free of bacilli. It therefore depends upon a fil- 

 terable and unknown virus. 



* "Circular No. 41 of Bureau of Animal Industry," U.S. Dept. of 

 Agriculture, Washington, D. C. 



