THE GLANDERS BACILLUS 359 



regular segmentation, but may exhibit lateral branching, 

 and may have club-shaped extremities. From these 

 features some place the glanders organism among the 

 Streptotrichece. The bacillus does not form spores, and is 

 probably non-motile, though in a hanging-drop prepara- 

 tion a very active Brownian movement is present. 



Staining reactions. The bacillus is Gram-negative, is 

 not acid-fast, and from young cultures stains readily 

 with the ordinary ahilin dyes. It is difficult to demon- 

 strate it in smears of glanders or farcy material, as a 

 majority of the organisms appears to be degenerate and 

 to stain badly, and the presence of deeply staining nuclear 

 detritus increases the difficulty. In sections, methylene- 

 blue staining with decolorisation in dilute acetic and 

 mordanting with tannin gives the best results (p. 366). 

 The bacillus shows dark staining dots when treated with 

 osmic acid, suggesting fat-globules (Shattock). 



Cultural characters. The Bacillus mallei is an aerobic, 

 and facultatively anaerobic organism. The growth on 

 gelatin at 22 C. is scanty and pale brownish in colour 

 without liquefaction. On glycerin agar it forms a thick 

 cream- or slightly brown-coloured growth, and on blood- 

 serum a somewhat amber-coloured growth, which after- 

 wards becomes brownish. The growth on potato at 

 37 C. is most characteristic, and practically diagnostic. 

 If the surface of the potato is inoculated with a loopful 

 of farcy pus or material from the centre of a glanders 

 nodule, the resulting growth is usually not distinctly 

 visible until the third day, when raised, translucent, 

 viscid, amber-yellow coloured growth or colonies, like 

 drops of honey, appear. With continued incubation the 

 colonies coalesce, the growth becomes thicker and fawn- 

 coloured, then reddish-brown, and finally generally 

 chocolate-brown. The growth is odourless, limited to the 

 site of implantation, and does not stain the potato. Broth 



