42 BACTERIOLOGY 



This solution keeps for some months. It is employed especially 

 where very intense action is required, as in staining spores, flagella, 

 and acid-proof bacteria. 



Loffler's Methylene Blue.— A very useful solution, which 

 keeps well, is LofHer's alkaline methylene blue: 



Saturated alcoholic solution of methylene blue 30 c.c. 



T-io,ooo aqueous solution of potassium hydroxide.. 100 c.c. 



This solution stains more intensely than simple methylene blue, 

 and also gives rise to useful differential staining in smears and 

 even in sections of tissue. 



Nocht-Romanowsky Stain. — This requires two solutions, one 



of ripened alkaline methylene blue, the other of eosin. 



• 



Solution I. 



Methylene blue 10 gram. 



Sodium carbonate 0.5 gram. 



Distilled water 100. o grams. 



Heat at 60" C. for two days until solution shows a slight purplish 

 color. 



Solution 2. 



Eosin, yellowish, water soluble 1.0 gram. 



Distilled water 100,0 c.c. 



In staining, a few drops of each of these solutions are mixed with 

 about 10 c.c. of distilled water in an Esmarch dish, and the smear, 

 which has previously been fixed in absolute methyl alcohol, is 

 floated on this mixture for about ten minutes. Considerable 

 practice is necessary before the best results are obtainable. 

 The method is especially useful , in staining blood films, and 

 protozoa in blood, in feces or in culture. 



Leishman's Stain. — ^Leishman has utilized the principle of 

 Jenner's stain^ and has added to it the important additional 

 constituents found in polychrome methylene blue by substituting 

 this for the ordinary methylene blue used by Jenner. 



. ' Jenner (Lancet, 1899, I, p. 370) first employed the solution of eosin and methy- 

 lene blue in methyl alcohol as a stain for blood films. 



