242 VETERINARY BACTERIOLOGY 



white, opaque colonies are formed. These generally become con- 

 fluent. The whole mass of the growth may be detached from the 

 surface of the medium. In bouillon, clouding occurs, then the 

 medium clears by sedimentation, with or without a pellicle. Upon 

 serum the organism produces outgrowths into the medium, and 

 resembles the B. pseudotuberculosis closely. Milk is not changed. 



Physiology. The organism is aerobic. Neither acid nor gas 

 is developed from carbohydrates. The thermal death-point is 

 about 65 with an exposure of fifteen minutes. 



Pathogenesis. Experimental Evidence. Subcutaneous inocu- 

 lations of the guinea-pig result in abscess formation and extension 

 along the lymph-channels. Introduced intraperitoneally into a 

 male guinea-pig, it commonly produces an orchitis which cannot 

 be readily differentiated from that produced by the glanders 

 bacillus. Nocard reproduced the disease in the horse by the 

 inoculation of pure cultures. 



Character of Lesions and Disease Produced. The subcutaneous 

 lymph-nodes are chiefly affected. They enlarge, and break 

 through to the surface, producing an abscess characterized by 

 suppuration. The clinical ^picture closely resembles that of farcy. 

 Involvement of the deeper glands and of the internal organs 

 occurs later in the progress of infection. 



Bacteriologic Diagnosis. This organism may be differen- 

 tiated from the true glanders bacillus by the fact that it is 

 gram-positive, while the latter is gram-negative. The pro- 

 duction of an orchitis in the male guinea-pig when injected 

 makes it necessary that mounts stained by Gram's method be 

 used to differentiate from B. mallei. In doubtful cases, pure 

 cultures should be grown upon the potato. 



Immunity. Nothing is known of the metabolic products of 

 the growth of the organism nor of methods of immunization or 

 of the body reactions to its presence. 



Transmission. The disease is probably transmitted through 

 skin lesions, possibly by inhalation or ingestion. 



Bacillus pyogcnes bovis 



Synonyms. Bacillus renalis bovis; B. pyelonephritidis bovis. 

 Infection Produced. Pyelonephritis, caseation of lymph- 

 glands, and chronic pneumonia in cattle. 



