206 BACTERIA 



are: Vibrio Metchnikovii; Vibrio proteus; Vibrio tyrogenum; and 

 Vibrio schuylkilliensis. There are no important pathogenic mem- 

 bers of this group except the cholera vibrio. 



GLANDERS BACILLUS 



Bacterium Mallei. 



Bacillus Mallei. 



Glanders Bacillus. 



Morphology and Stains. Slender rods 2 to 3/x. in length con- 

 taining no true spores, but shining chromatophilic bodies (Babes- 

 Ernst granules). In old culture, long club-like threads appear, 

 which exhibit true branching. This organism is not motile, and 

 has no flagella. It is stained with difficulty by ordinary methods, 

 and not at all by Gram's method. 



Vital Activities. It is a facultative aerobe, growing feebly in 

 the absence of air, and best at 37C., in glycerine agar. Resists 

 drying but feebly. Its thermal death-point is 5SC., ten minutes' 

 exposure. 



Chemical Activities. Produces a brown pigment on potato, 

 also mallein, and a little indol in old bouillon cultures. It forms 

 no gas. 



Cultures. On gelatine it produces small punctiform colonies 

 that are white, and become, after a time, surrounded by a distinct 

 halo. The colonies are often very delicate and ragged. The gela- 

 tine is not liquefied. On agar the growth is best if glycerine is 

 present, but is not characteristic. Bouillon cultures cause an 

 abundant sediment, above which the medium is clear. Milk is 

 coagulated. On potato the growth is characteristic. The color 

 is, at first, yellowish-white like honey, becoming, finally, reddish- 

 brown. The potato is much darkened. 



Pathogenesis. This organism is pathogenic for horses and 

 man; 50 percent of men succumb after infection. Horses, asses, 

 cats, dogs, sheep, and goats are susceptible in the order mentioned. 

 Cattle and birds are immune. In horses the disease is known as 



