SECTION TWO 



J.S.B. STAIN 

 A rapid, water-soluble stain for malaria parasites 



(After Jaswant Singh & Bhattacharji, 1944) 



Note: Both J.S.B. No. i and No. 2 stains can be purchased 

 ready prepared, both in the powder and the hquid forms, but for 

 those workers who prefer and have the time to make their own, the 

 following recipes are given: 



J.S.B. Stain No. i 



Preparation of the dry stain 



Methylene blue (zinc free), extra 



pure . . . . . . . . 0-5 gm. 



Tap water . . . . . . 400 ml. 



Dissolve thoroughly, then add : 



Sulphuric acid, 1% aqueous . . 3 ml. 



Potassium dichromate, 0-5% 



aqueous . . . . . . 100 ml. 



Technique: 



1. Mix thoroughly; a heavy amorphous precipitate of purple 

 coloured methylene blue chromate forms. 



2. The resultant mixture is heated very gently, under a reflux 

 condenser, over a very low flame, on a water bath, or on an electric 

 hotplate. 



Note: It is stated that the duration of heating is always guided 

 by the appearance of a deep blue colour, and not by any fixed 

 time factor. 



Sometimes, although the solution may appear blue while 

 boiling, it may turn green on shaking or cooling, in which case 

 it should be boiled again for a further period. However, four to 

 six hours boiling over a flame or five to six hours on a water bath 

 is usually needed. 



3. When the solution turns blue, it should be cooled to room 

 temperature, then filtered, and the precipitate collected. 



4. The precipitate is left to dry at room temperature in the 

 air, or in a dessicator. 



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