CHAPTER XXXIX 

 BACILLUS MALLEI AND GLANDERS 



(Glanders Bacillus) 



GLANDERS is an infectious disease prevalent chiefly among horses, 

 but transmitted occasionally to other domestic animals and to man. 

 The microorganism causing the disease, though seen and described 

 by several earlier authors, was first obtained in pure culture and 

 accurately studied by Loeffler and Schiitz 1 in 1882. 



Morphology and Staining. The glanders bacillus or B. mallei 

 is a rather small rod with rounded ends. 2 Its length varies from 

 3 to 4 micra, its breadth from 0.5 to 0.75 micron. Variation in size 

 between separate individuals in the same culture is characteristic. 

 The rods are usually straight, but may show a slight curvature. 

 The bacillus is non-motile. There are no flagella and no spores are 

 formed. The grouping of the bacilli in smears shows nothing very 

 characteristic. Usually they appear as single bacilli lying irregularly 

 parallel, often in chains of two or more. In old cultures, involution 

 forms appear which are short, vacuolated, and almost coccoid. 



While the glanders bacillus stains rather easily with the usual 

 anilin dyes, it is so easily decolorized that especial care in preparing 

 specimens must be observed. Stained in the usual manner with 

 methyleiie-blue, it shows marked irregularity in its staining quali- 

 ties; granular, deeply staining areas alternating with very faintly 

 stained or entirely unstained portions. This diagnostically helpful 

 characteristic has been variously interpreted as a mark of degenera- 

 tion or a preparatory stage for sporulation. It is probably neither 

 of the two, but an inherent irregularity in the normal protoplasmic 

 composition of the bacillus, not unlike that of B. diphtherias. The 

 bacillus is decolorized by Gram's method of staining. 



Cultivation. The glanders bacillus is easily grown on all of the 

 usual meat-infusion media. It is practically indifferent to moderate 



1 Loeffler und Schutz, Deut. med. Woch., 1882. 



2 Loeffler, Arb. a. d. kais. Gesundheitsamt, 1886. 



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