CHAPTER XXXVI 



BACILLUS MALLEI 

 (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 ' in 1882. 



Morphology and Staining. — The glanders bacillus or B. mallei is a 

 rather small rod with rounded ends.^ Its length varies from 3 to 4 

 micra, its breadth from 0.5 to 0.75 micron. Variation in size be- 

 tween separate individuals in the same culture is characteristic. The 

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

 is non-motUe. 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 methylene-blue, 

 it shows marked irregularity in its staining qualities; 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 degeneration or a preparatory stage for sporula- 

 tion. It is probably neither of the two, but an inherent irregularity in 

 the normal protoplasmic composition of the bacillus, not unlike that 

 cf B. diphtheriae. The bacillus is decolorized by Gram's method of 

 staining. 



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



> Loeffler und Schiitz, Deut. med. Woch., 1882. 



" Loefflidr, Arb. a", d. kais. Gesundheitsamt, 1886. 



528 



