IX SUSCEPTIBLE ANIMALS. 509 



Morphology. Bacilli with rounded ends, about twice as long as 

 broad, and one-third smaller than the bacillus of typhoid fever 

 (Eberth and Schimmelbusch). The bacillus of hog cholera is shorter 

 and more slender than the Marseilles bacillus, and the bacillus of 

 Loffler and Schiitz is still smaller (Rietsch and Jobert). 



In stained preparations the extremities of the rods are usually 

 deeply stained, while the central portion remains unstained :i polar 

 staining. " By Loffler's method of staining the presence of flagella 

 may be demonstrated (Frosch). 



Stains readily with the aniline dyes usually employed, but does 

 not retain its color When treated by Gram's method. 



Biological Characters. An aerobic (facultative anaerobic), 

 non-liquefying, actively motile bacillus. Grows readily at the 

 room temperature, and is distinguished from the bacillus of septi- 

 caemia hsemorrhagica by its active movements and more rapid and 

 abundant development in the various culture media usually em- 

 ployed. It is distinguished from the bacillus of hog cholera by pro- 

 ducing phenol and indol in solutions containing peptone, by causing 

 coagulation of milk, and by producing an acid reaction in this fluid. 

 Grows in culture media having an acid reaction. 



Rietsch and Jobert give the following account of the characters 

 of growth in various culture media, as compared with the bacillus of 

 hog cholera and the bacillus of Schweineseuche (Loffler, Schutz) : 



Gelatin streak cultures. At the end of twenty-four hours this 

 bacillus had developed considerably, while the growth of the hog- 

 cholera bacillus was scarcely to be discerned with the naked eye, and 

 the bacillus of Schweineseuche did not form a visible growth until 

 the end of forty-eight hours. After several days the bacillus of 

 swine plague (Marseilles) formed an opaque, yellowish- white streak, 

 which, when examined with a low-power lens, had a brown color by 

 transmitted light and a bluish- white color by reflected light. The 

 streak of the Loffler-Schiitz bacillus was not so thick and not so 

 opaque, and was made up of small, nearly transparent colonies ; the 

 hog-cholera bacillus came between the other two. Upon blood 

 serum, agar, and glycerin-agar the Marseilles bacillus grew more 

 rapidly than the other two, forming a layer which was opaque and 

 of a white color, with bluish and reddish reflections. Upon potato 

 it formed a thick, opaque, yellowish layer, while the growth of the 

 hog-cholera bacillus was much thinner and that of the Loffler-Schiitz 

 bacillus scarcely to be seen. In bouillon the Loffler-Schiitz bacillus, 

 at the end of three days at 37 C., had not produced any perceptible 



lings and from other sources, the result was exactly the opposite viz., a decided 

 production of alkali in milk and identity with the hog-cholera bacillus of Salmon." 



