Staining 



707 



conjoined individuals may occasionally be found. Long threads 

 are never formed. 



When stained with ordinary aqueous solutions of the aniline 

 dyes, or with Loffler's alkaline methylene-blue, the bacillary sub- 

 stance does not usually appear homogeneous, but, like that of the 

 diphtheria bacillus, shows marked inequalities, some areas being 

 deeply, some faintly, stained. 



The bacillus is non-motile, has no flagella, and does not form 

 spores. 



Staining. 'The organism can be stained with the watery anilin- 

 dye solutions, but not by Gram's method. The bacillus readily 

 gives up the stain in the presence of decolorizing agents, so is dif- 



^ i g^fy-w J& V 



: > xLi:^ x *1* r H 



Fig. 286. Bacillus mallei, from a culture upon glycerin agar-agar. X 1000 

 (Frankel and PfeifTer). 



ficult to stain in tissues. Lofner accomplished the staining by 

 allowing the sections to lie for some time (five minutes) in the alka- 

 line methylene-blue solution, then transferring them to a solution of 

 sulphuric and oxalic acids: 



Concentrated sulphuric acid 2 drops 



Five per cent, oxalic acid solution i drop 



Distilled water 10 cc. 



for five seconds, then to absolute alcohol, xylol, etc. The bacilli 

 appear dark blue upon a paler ground. This method gives very good 

 results, but has been largely superseded by the use of Kiihne's car- 

 bolmethylene-blue. 



Methylene-blue i . 5 



Alcohol 10 . o 



Five per cent, aqueous phenol solution 100 . o 



Kiihne stains the section for about half an hour, washes it in water, 



