Bacilli Resembling the Typhoid Bacillus 625 



BACILLUS PSITTACOSIS (NOCARD) 



General Characteristics. A motile, flagellated, non-sporogenous, aerobic, 

 optionally anaerobic, non-chromogenic, aerogenic, pathogenic, non-liquefying 

 bacillus, staining by the ordinary methods, but not by Gram's method. 



This micro-organism was discovered by Nocard,* who first observed it in 1892 

 in certain cases of psittacosis, or epidemic pneumonia, traceable to infection from 

 diseased parrots. The original paper contained an excellent account of the spe- 

 cific organism. 



The subsequent work of Gilbert and Fournierf shows the specificity of the 

 micro-organism to be quite well established and Nocard 's characterizations 

 accurate. 



Morphology. The bacillus is short, stout, rounded at the ends, and actively 

 motile. It is provided with flagella, but forms no spores. It resembles the 

 typhoid and the colon bacilli and is evidently a form intermediate between 

 the two. 



Isolation. Gilbert and Fournier succeeded in isolating it from the blood of a 

 patient dead of psittacosis, and from parrots, by the use of lactose-litmus agar. 

 The organism does not alter the litmus, and if a small percentage of carbolic acid 

 be added to the culture-media, it grows as does the typhoid bacillus. 



Cultivation. The colonies, agar-agar and gelatin cultures, closely resemble 

 those of the typhoid fever organism. Upon potato it more closely resembles the 

 colon bacillus. Bouillon becomes clouded. 



Metabolic Products. In bouillon containing sugars the micro-organism is 

 found to ferment dextrose, but not lactose. Milk is not coagulated and not 

 acidulated. No indol is formed. 



Pathogenesis. Bacillus psittacosis can be immediately differentiated from the 

 typhoid and colon bacilli by its peculiar pathogenesis. It is extremely virulent 

 for parrots, producing a fatal infection in a short time. White and gray mice and 

 pigeons are equally susceptible. Ten drops of a bouillon culture injected in the 

 ear- vein of a rabbit 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, character- 

 ized by the presence of the bacillus in the blood, traceable to diseased parrots, 

 having been reported. 



Differentiation. Bacillus psittacosis can best be differentiated from the ty- 

 phoid 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, invad- 

 ing their tissues when they become ill, or whether it is a purely pathogenic 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 



* " Seance du Conseil d'hygiene publique et Salubrite du Departement de la 

 Seine," March 24, 1893. 



t"Comptes rendu de la Societe de Biologic," 1896; "La Presse medicale," 

 Jan. 16, 1897. 



