MODIFICATION OF LOEFFLER'S FLAGELLA STAIN 185 



results may be obtained from fairly large drops, but ordinarily 

 they should not be over 2 or 3 mm. in diameter. As soon as the 

 drops are dry, the preparation is ready for the mordant which 

 is prepared as follows: 



Solution A 



parts 



Ferric chloride (1-20 aqueous solution) 1 



Saturated aqueous solution tannic acid 3 



This solution improves with age, and should be at least a week or 

 two old. It should be kept made up in stock but filtered before 

 using, although when using at frequent intervals, it need not be 

 filtered except every few days. 



Solution B 



Anilin-oil 1 



95 per cent, alcohol 4 



About eight drops of solution A are placed on the cover-glass, 

 this is followed immediately by one drop of solution B, and the 

 combination is allowed to act at room temperatures for two 

 minutes, then washed off with water, and the water drained off 

 by touching the edge of the cover-glass to a piece of filter paper. 

 The preparation should not be blotted as there is danger of 

 scratching the film. Then the cover-glass is flooded with the 

 stain which may be carbol-fuchsin, 1 per cent safranin in 50 

 per cent alcohol, anilin-oil-gentian-violet, or Loeffler's alkaline 

 methylene blue. While I have had success with all of these 

 stains, the stain which I prefer, and use most frequently is a 

 special methylene blue prepared as follows : 



parts 



Saturated alcoholic methylene blue 30 



Potassium hydroxide (1 : 10,000) 100 



Solution B of mordant 13 



It is my practice to make up this stain by adding to 30 cc. of 

 Loeffler's methylene blue, 3 cc. of mordant solution B. This 

 stain is immediately ready for use and keeps well. The blue 

 gives a color which is easier on the eye than the red of fuchsin 

 or safranin. 



The stain is allowed to act for two or three minutes at room 

 temperatures, then the cover-glass is washed thoroughly with 

 water, allowed to dry, and mounted in balsam. 



