248 VETERINARY BACTERIOLOGY 



the pigeon, rather than the mouse, as a test-animal. The serum 

 may be used curatively or prophylactically. Amounts up to 30 c.c. 

 are used in curing the disease. In cases not too far advanced it 

 arrests the disease, and has been shown to reduce the mortality 

 materially. The injection of the serum prophylactically results 

 in temporary immunity only, hence it is customary to establish an 

 active immunity by injection of the specific organism, the culture 

 and the serum being mixed together or injected separately at the 

 same time. This method of immunization has proved of such 

 value that it is extensively used in Europe. The active immunity 

 developed as a result of the combined method lasts for periods of 

 six months to a year or even longer. 



Bacteriologic Diagnosis. Smears from the spleen, sometimes 

 from the blood, will show the characteristic slender, gram-positive 

 bacillus. Isolation in gelatin plates gives a characteristic type of 

 colony. The stab culture in gelatin is also diagnostic. 



Transmission. The specific organism may be demonstrated 

 in the feces of an infected individual. It may gain entrance di- 

 rectly through the skin, but probably, in most instances, the infec- 

 tion atrium is the alimentary tract. Typical virulent bacilli and 

 non-virulent forms have been repeatedly isolated from healthy 

 animals. It is evident that the interrelationships of this organism 

 and the body are quite complex. 



Bacillus murisepticus 



Disease Produced. Mouse septicemia. 



Koch, in 1878, called attention to the fact that the injection 

 of putrid meat infusion into a mouse resulted in a septicemia due 

 to a non-motile, minute rod. It is of importance chiefly because 

 of its resemblance to the Bacillus rhusiopathice. It has been 

 isolated from a variety of sources in nature, and has been known to 

 cause epidemics in mice kept for experimental purposes. There 

 are no marked cultural characters which may be used to differen- 

 tiate the two organisms, and morphologically they are likewise 

 very similar. It is claimed by some that the B. murisepticus is 

 somewhat more slender than the B. rhusiopathice. It has been 

 found possible to immunize the rabbit against the latter by injec- 

 tions of the former. However, it has not been found possible to 



