STAINING OF FLAGELLA 91 



The prepared cover -glasses, dried and fixed in the 

 manner already described, are now treated with the mor- 

 dant. The simple mordant, as above, can be used for 

 some species, but in most cases, as already mentioned, it 

 must be rendered alkaline or acid, to an extent which varies 

 with the various organisms. The following are the addi- 

 tions of acid and alkali respectively made to the mordant as 

 recommended by Dr. Loffler for particular organisms : 



22 drops = 1 CO. 



Spirillum cholercB Asiaticce 1 drop of acid to 16 c.c. of mordant. 



,, rubrum 9 drops „ ,, „ ,, 



„ MetchniJcoffi ... 4 „ „ „ „ „ 



Bacillus pyocyaneus ... 5 ,, „ ,, „ „ 



Spirillum conoentricum ... ,, „ „ „ ,, 



Bacillus mesentericus vul- 



gatus 



Micrococcus agilis ... 20 



Typhoid bacillus 22 



Bacillus subtihis 29 



Bacillus cedematis maligni 36 

 Bacillus of symptomatic ) 

 a/nthrax ... ... ... ) 



4 drops of alkali to 16 c.c. of mordant. 



35 



The mordant, with the proper amount of acid or alkali 

 added, is run from a pipette on to the cover-glass, and the 

 latter is gently warmed over a flame with constant move- 

 ment until steam just begins to form. On no account 

 should it be allowed to boil, for if bubbles are once formed 

 the preparation is spoiled, as a fine precipitate of mordant 

 is produced, which becomes stained later on and obscures 

 fiagella. 



The heating must only last for from half to one minute ; 

 the liquid is poured off, and the cover-glass thoroughly 

 washed with water; it is allowed to dry in the ordinary 

 way. The preparation is then stained with a few drops of 

 5 per cent, aniline-water solution of fuchsine. The cover- 

 glass may be gently warmed for about a minute, after 



