CULTIVATION OF BACILLUS MALLEI. 2/9 



amount of growth occurs down to 21 C., a temperature above 

 25 C. is always desirable. 



On agar and glycerin agar in stroke-cultures growth appears 

 along the line as a uniform streak of greyish-white colour and 

 somewhat transparent appearance, with moist-looking surface, 

 and when touched with a needle is found to be of rather slimy 

 consistence. Later it spreads laterally for some distance, and 

 the layer becomes of slightly brownish tint. On serum the 

 growth is somewhat similar but more transparent, the separate 

 colonies being in the form of round and almost clear drops. In 

 sub-cultures on these media at the body temperature growth is 

 visible within twenty-four hours, but when fresh cultures are 

 made from the tissues it is not visible till the second day. 

 Serum, however, is much more suitable for cultivating from the 

 tissues than the agar media; on the latter it is sometimes difficult 

 to obtain growth. 



In broth, growth forms at first a uniform turbidity, but soon 

 settles to the bottom, and after a few days forms a pretty thick 

 flocculent deposit of slimy and somewhat tenacious consistence. 



On potato at 30 to 37 C. the glanders bacillus flourishes 

 well and produces a characteristic appearance ; incubation at a 

 high temperature, however, being necessary. Growth proceeds 

 rapidly, and on the third day has usually formed a transparent 

 layer of slightly yellowish tint, like clear honey in appearance. 

 On subsequent days, the growth still extends and becomes 

 darker in colour and more opaque, till about the eighth day it 

 has a reddish-brown or chocolate tint, while the potato at the 

 margin of the growth often shows a greenish-yellow staining. 

 The characters of the growth on potato along with the micro- 

 scopical appearances are quite sufficient to distinguish the glan- 

 ders bacillus from every other known organism (sometimes the 

 cholera organism and the B. pyocyaneus produce a somewhat 

 similar appearance, but they can be readily distinguished by their 

 other characters). Potato is also a suitable medium for starting 

 cultures from the tissues ; in this case minute transparent colo- 

 nies become visible on the third day and afterwards present the 

 appearances just described. 



Powers of Resistance. The glanders bacillus is not killed at 

 once by drying, but usually loses its vitality after fourteen days 

 in the dry condition, though sometimes it lives longer. It is not 



