46 GENERAL BACTERIOLOGY LESSON x 



(g) Pour a little aniline oil over the specimen, which is 

 now quite black, and by alternately tilting first one and 

 then the other end of the slide, allow the oil to flow to 

 and fro over the section. The aniline oil will take up the 

 gentian-violet greedily, and gradually become saturated. 

 When this has taken place, remove the oil with blotting- 

 paper and pour fresh oil over the specimen. Repeat this 

 process till no more stain comes away. 



(h) Eemove the oil with blotting-paper, and wash the speci- 

 men thoroughly with xylol, which must be frequently changed. 

 (i) Mount in xylol balsam and examine with low and 

 high powers. 



It is essential that the whole process be completely 



carried through with the section on the slide. 

 Sections of Mycetoma (Madura disease) may be 

 stained in the same manner. 



Staining of Flagella (after Pitfield) 



(1) Prepare the following solution : ^~ ) 



(a) Cold saturated solution of alum 10 cc. Saturated 

 alcoholic solution of gentian-violet 2 cc.ft ) 



To this add (&) 10(cc. of a cold aqueous solution of 

 tannic acid (10 per cent). 



(2) Prepare a suspension of typhoid bacilli, cover-slips 

 and films as on pp. 38 and 39. 



(3) Cover the film with the stain, and keep gently 

 steaming on a copper section lifter for 1-2 minutes. 



(4) Wash in water, dry and mount. 



Examine with ^- in. oil immersion. The results are 

 almost always excellent, and remarkably easily 

 obtained. 



