176 



BACILLUS OF CHICKEN CHOLERA. 



Perroncito, Pasteur (1880). 



SYNONYMS OF CHICKEN OK FOWL CHOLERA. CHOLERA DES POULES (Fr.) ; 

 HUHNER-, GEFLUGEL-CI10LERA {Germ.}. 



Origin. In the blood, organs and excreta of chicken which 

 have thejdisease. A somewhat similar disease of chickens, occur- 

 ing in Russia, has been shown to be due to the Vibrio Metchnikovi 

 which resembles very closely the vibrio of Asiatic cholera. 



Form. Small short rods which have rounded ends and are 

 frequently in pairs, rarely in long threads. At times the form is 

 almost that of a coccus. 



Motility. Has no motion. 



Sporulation. Spores have not been observed. Nevertheless, 

 it possesses considerable power of resistance and can withstand the 

 acidity of the gastric juice. 



Anilin Dyes. Usually stain the ends first while the center 

 remains uncolored bi-polar stain. The appearance then is that of 

 a diplococcus. On more intense staining the entire rod becomes 

 colored. Gram's method is not applicable. 



Growth. Is rather slow. 



Plates Colonies appear in ; few days on gelatin plates as minute white 

 dots, which, under the microscope, are seen to be roundish plates with sharp, 

 smooth borders. The contents ure finely granular, show concentric rings and 

 are yellowish in color. No liquefaction. 



Ktich Cultures. Forms in gelatin, a delicate white line or row of dots 

 along the line ot inoculation. On the surface it forms a delicate whitish 

 growth which sprctids veiy slowly. 



Streak Culture* on aaar it develops as a thick, glistening, grayish- 

 white mass. No growth <>n potatoes at ordinary temperatures, but in the in- 

 cubator in u few tla\ s it gives rise to a yi llowi^h-gray transparent covering. 



Oxygen requirements. Is a facultative anaerobe. 



Temperature. Grows at ordinary temperature and also in the 

 incubator. 



Behavior to Gelatin. Does not liquefy. 



Attenuation. Artificial cultures soon lose their virulence. It 

 was in connection with this organism that attenuation was first ob- 

 served by Pasteur (1880). Influence of oxygen, of heat. 



Immunity. Is produced in chickens and pigeons by inocula- 

 tion with first and second vaccines. 



Pathogenesis. Chickens, geese, pigeons, sparrows, mice and 

 rabbits are susceptible. Guinea-pigs, sheep, horses are less suscep- 

 tible and only local abscesses form. After death the bacilli are found 

 distributed throughout the body a true septicaemia. 



Infection. Usually results in chicken through the food 

 and along the alimentary canal. May possibly also occur through 

 scratches and wounds. 



