164 ESSENTIALS OF BACTERIOLOGY. 



CHAPTER IY. 



BACTERIA PATHOGENIC FOR ANIMALS BUT NOT FOR MAN. 



Bacillus of Symptomatic Anthrax, (Bellinger and Feser.) 



(Charbon symptomatique. Arloing, Cornevin, and Thomas.) 



Origin. This bacillus, described already in 1879, has only 

 lately been isolated, and by animal inoculation shown to be the 

 cause of the " black-leg" or u quarter evil" disease of cattle. 



Form. Large slender rods, which swell up at one end or in 

 the middle for the spore. (See Plate IV., Fig. 1.) 



Properties. They are motile, and liquefy gelatine quite 

 rapidly. 



A rancid odor is developed in the cultures. 



Cultures. The growth occurs slowly, and only in an atmo- 

 sphere of hydrogen, being very easily destroyed by oxygen and 

 carbon dioxide ; grows best at blood heat ; under 15 C. no 

 growth. 



Glucose-gelatine. In a few days little round colonies develop, 

 which, under low power, show hairy processes around a compact 

 centre. 



Stab Cultures in full test tubes. The first growth in the lower 

 portion of the tube not very characteristic. Gases develop 

 after a few days, and the gelatine becomes liquid. 



Agar at brood temperature, in 24 to 48 hours, an abundant 

 growth with a sour odor and abundant gas formation. 



Staining. Ordinary methods. Gram's method is not appli- 

 cable to the rods ; but the spores can be colored by the regular 

 double stain for spores. 



Pathogenesis. If a small amount of the culture be injected 

 under the skin of a guinea-pig, in twenty hours a rise of tempera- 

 ture, pain at the site of injection, and in a few hours more 

 death. At the autopsy, the tissues blackened in color and 

 soaked with a bloody serous fluid ; in the connective tissue large 

 collections of gas, but only in the neighborhood of the point 

 of infection. The bacilli are found in great numbers in the 



