288 THE BACILLUS OF SWINE ERYSIPELAS 



help in diagnosis and in differentiating the disease from hog cholera [swine 

 fever]. 



The following observations and experiments should be made : 



1. Stain blood films and smear preparations of the lymphatic glands, 

 spleen and bone marrow by Gram's method, etc. and examine them for the 

 bacillus (vide " Microscopical appearance "). 



2. Sow cultures from the spleen in broth and on gelatin. 



3. Inoculate pigeons and guinea-pigs with broth cultures. 

 Guinea-pigs it will be remembered are immune to swine erysipelas, but 



they are very susceptible to hog cholera [or swine fever]. This experiment 

 therefore will differentiate between the two diseases. 



The bacillus of mouse septicaemia (Koch). 



(Bacterium murisepticum.) 



The septicsemic disease of the domestic mouse (Mus musculus), investigated by Koch, 

 is due to a small bacillus, similar to that of swine erysipelas, but on inoculation somewhat 

 less rapidly fatal than the latter organism. It is not pathogenic for the field mouse 

 (Arvicola arvalis) nor for pigeons nor rabbits. But if its virulence be increased by numerous 

 passages through mice a virus is ultimately obtained which, on intra-venous inoculation, 

 proves fatal to pigeons. 



The symptoms observed in experimentally-infected mice are drowsiness, blepharitis 

 and a spasmodic form of respiration. The disease finally terminates fatally. Bacilli 

 are to be found in large numbers in the blood and in the internal organs. 



The morphological characteristics and staining reactions of this organism are the same 

 as those of the bacillus of swine erysipelas. The cultures of the two organisms are very 

 much alike ; there is, however, this difference that the growth of the bacterium murisep- 

 ticum in gelatin is more cloudy and the radiating filaments are not so well marked. 



The serums of animals immunized against the bacillus of swine erysipelas agglutinate 

 the bacillus of mouse septicaemia (Overbeck). This affords definite proof that the latter 

 bacillus is not a distinct species [but merely a variety of the bacillus of swine erysipelas 

 adapted to its special host.] 



