METHOD FOR STAINING FLAG ELL A. 187 



This solution represents the mordant. A few drops 

 of it are to be placed upon the film of bacteria on the 

 cover-slip, which is then to be held over a flame until 

 the solution begins to steam. It should not be boiled. 

 After steaming, the mordant is washed off in water and 

 finally in alcohol. The bacteria are then to be stained 

 in a saturated aniline-water-fuchsin solution. 



When treated in this way different bacteria behave 

 differently : the flagella of some stain readily in the 

 above solutions ; others require the addition of an alkali 

 in varying quantities ; while others stain best after the 

 addition of acids. To meet these conditions an exact 

 1 per cent, solution of caustic soda in water must be 

 prepared, and also a solution of sulphuric acid in water 

 of such strength that one cubic centimetre will be ex- 

 actly neutralized by one cubic centimetre of the alkaline 

 solution. 



For different bacteria which have been studied by 

 this method Loffler recommends the one or the other of 

 these solutions to be added to the mordant in the follow- 

 ing proportions. 



Of the acid solution : 



For spirillum choleras Asiaticse, i to 1 drop of acid to 16 c.c. of mordant. 



For spirillum rnbrum, 9 



For spirillum Metschnikoffi, 4 " " 



For bacillus pyocyaneus, 5 



For spirillum concentricum, no addition of either acid or alkali. 



Of the alkaline solution : 



For bacillus mesentericiis mdgatus, 4 drops of alkali to 16 c.c. of mordant. 



For micrococcus agilis, 20 



For bacillus typhomts, 22 



For bacillus subtilis. 28-30 " " " " 



For bacillus nedematis maligni, 36-37 " 

 For bacillus anthracis symp- ) 

 tomatici, 



