THE EXAMINATION OF MICRO-ORGANISMS 621 



The Glanders Bacillus. 



The Bacillus mallei is a short rod (2-5 /a) with rounded ends. 



Bipolar or beaded in stained preparations, no spores. 



Non-motile, but active Brownian movement. A creamy growth on 

 glycerine agar, does not liquefy gelatin. On potato, four days, looks 

 like drops of honey, but later darkens to chocolate colour, but the 

 potato remains unstained. Gram-negative. Does not readily stain at 

 all; methylene blue, and then 4 to 5 per cent, acetic for ten seconds is 

 the best stain. 



The Spirillum cholerae asiaticsB. 



Koch's comma bacillus is a curved rod (2-.-; ^) vS-shaped in liquid 

 media, actively motile, one flagellum, no spores, desiccation and sun- 

 light rapidly fatal. Gram-negative. Readily stained with aniline 

 dyes, grows readily on most media, but a slight alkaline reaction is 

 necessary. Forms indol rapidly, creamy growths on agar. 



General turbidity in broth and H2S in both. Occurs in flakes in 

 a "fish in stream" position. For bacterial diagnosis, see Cholera. 



The Finkler-Prior spirillum may be confounded with it. These 

 are thicker and longer than the Koch's comma bacillus, and it can be 

 differentiated by the cultural reactions: — 



Cultural Characters KocK s Comma Bacillus Vibrio Proteus 



(Finkler-Prior Spirillum) 



Gelatin stab culture ... Slow liquefaction Rapid liquefaction 



Potato at 37°C Slow light greyish brown Rapid slimy yellow growth 



growth ... 



Peptone water Indol reaction marked Indol reaction feeble or nil 



within twelve hours ... in three days 



t 



TO PREPARE CULTURES. 



For nutrient media, test-tubes, Petri dishes and other vessels are 

 used. 



Wash all with 25 per cent. HCl, rinse well with water and drain, 

 rinse with alcohol and dry, plug test-tubes with cottonwool, sterilize 

 at 140° C. 



The common media are : — 



Beef Broth. 



Use I lb. of beef steak, free from fat and connective tissue, mince, 

 add 1,000 c.c. of water, boil and stir well for thirty minutes. Strain 

 through muslin, add water up to 1,000 c.c, add sodium chloride, 

 5 grm., and peptone, 10 grm., boil for five minutes, carefully neutralize 

 with sodium hydrate solution, make it slightly alkaline to litmus, then 

 boil for ten minutes, shaking well, filter it into flasks plugged with 

 sterile cottonwool. 



