GLANDERS GROUP 



251 



It sometimes shows some granular differentiation of the cytoplasm, 

 resembling the diphtheria bacillus. It is not acid fast and is 

 gram-negative . 



Isolation and Culture. Bacillus mallei is rarely in pure cul- 

 tures in the nasal discharges, so that for its isolation from such 

 sources a special technic is necessary. It is customary to inject 

 intraperitoneally a male guinea-pig with a small quantity of the 

 discharge from an ulcer, mixed with a little bouillon or physiologic 

 salt solution. Within two to four days the testicles swell and give 

 evidence of acute inflammation. The animal is then killed, a 

 testis removed and opened under aseptic conditions, and the con- 

 tents of one of the small abscesses or foci of inflammation removed 

 on a sterile platinum needle , ^ 



to suitable media. 



Bacillus mallei grows 

 upon the ordinary culture- 

 media, particularly upori 

 those that contain glycerin, 

 upon blood-serum, and 

 potato. The colonies upon 

 agar and glycerin-agar 

 plates are whitish or yellow- 

 ish, glistening, usually cir- 

 cular. Upon the slanted 

 medium the colonies are 

 coalescent and form a 

 moist, shining layer. In 

 bouillon and glycerin bouillon B. mallei produces an initial tur- 

 bidity, followed by sedimentation; a shining white pellicle is 

 likewise formed when the medium is not shaken. On blood- 

 serum the colonies are first discrete, clear, yellowish, viscous, 

 hemispheric drops which coalesce to form "a transparent layer 

 over the surface; this later becomes gray and opaque. Gela- 

 tin is not liquefied. The growth upon potato is perhaps the 

 most characteristic. It may be described as forming within forty- 

 eight hours a yellow, honey-like, semitransparent growth that 

 gradually becomes brownish or amber in tint. The potato itself 

 is tintd greeenish or greenish brown. This reaction is not charac- 



Fig. 106. Bacillus mallei from glycerin 

 agar (X 1000[ (Frankel and Pfeiffer). 



