CHAPTER XXXI. 



GLANDERS BACILLUS (BACILLUS MALLEI). 



THIS bacillus was discovered and proved to be the cause of glanders, 

 by isolation in pure culture and communication to animals by inocu- 

 lation, by several bacteriologists almost at the same time (1882) . The 

 bacilli were first obtained in impure cultures by Bouchard, Capitan, 

 and Charrin, and first accurately studied in pure culture by Loeffler 

 and Schiitz. They are present in the recent nodules in animals affected 

 with glanders, and in the discharge from the nostrils, pus from the 

 specific ulcers, etc., and occasionally in the blood. 



Morphology. Small bacilli with rounded or pointed ends, from 

 nutrient agar cultures, Q.25/J. to 0.5/* broad and from 1.5/* to 5/* long; 

 usually single, but sometimes united in pairs, or growing out to long 

 filaments, especially in potato cultures. The bacilli frequently break 

 up into short, almost coccus-like elements (Fig. 126). 



Staining. The bacillus mallei stains with difficulty with the aniline 

 colors, best when the aqueous solutions of these dyes are made feebly 

 alkaline; it is decolorized by Gram's method. This bacillus presents 

 the peculiarity of losing very quickly in decolorizing solutions the color 

 imparted to it by the aniline-staining solutions. For this reason it is 

 difficult to stain in sections. Loeffler recommends his alkaline methy- 

 lene-blue solution for staining sections, and for decolorizing a mixture 

 containing 10 c.c. of distilled water, 2 drops of strong sulphuric acid, 

 and 1 drop of a 5 per cent, solution of oxalic acid; thin sections to be 

 left in this acid solution for five seconds. 



Biology. An aerobic, non-motile bacillus, whose molecular move- 

 ments are so active that they have often been taken for motility. It 

 grows on various culture media at 37 C. Development takes place 

 slowly at 22 C. and ceases at 43 C. The bacillus does not form 

 spores. Exposure for ten minutes to a temperature of 55 C., or for 

 five minutes to a 3 to 5 per cent, solution of carbolic acid, or for two 

 minutes to a 1 : 5000 solution of mercuric chloride, destroys its vitality. 

 As a rule, the bacilli do not grow after having been preserved in a 

 desiccated condition for a week or two; in distilled water they are also 

 quickly destroyed. It is doubtful whether the glanders bacillus finds 

 conditions in nature favorable to a saprophytic existence. 



Cultivation. (For methods of separation see page 411.) It grows 

 well in the incubating oven on glycerin agar. Upon this medium at 

 the end of twenty-four to forty-eight hours, whitish, transparent colonies 

 are developed, which in six or seven days may attain a diameter of 

 7 or 8 mm. On blood serum a moist, opaque, slimy layer develops, 



