CHAPTER IV 



PREPARATION OF STAINING SOLUTIONS 

 Saturated alcoholic solutions of stains are prepared 

 by covering an arbitrary amount of stain with absolute 

 alcohol. The solution is saturated as long as any of the 

 stain remains undissolved at the bottom of the vessel. 

 Other solutions necessary for the preparation of stains are: 



1. Solution of potassium hydrate in water i : 10,000. 



2. Solution of carbolic acid in water (5 per cent.). 



3. Anilin- water, prepared by shaking anilin-oil with 

 water (2 per cent.) and filtering twice through the same 

 paper. It should be perfectly clear. 



The staining-bottles usually employed have a capaci- 

 ty of about 30 c.c. The following amounts will nearly 

 fill them: 



1. Loeffler's methylene-blue : 



Saturated alcoholic solution of methylene-blue 9 c.c. 

 Potassium hydrate in distilled water i : 10,000 21 c.c. 



2. Ziehl-Neelsen's carbol-f uchsin : 



Saturated alcoholic solution of f uchsin 3 c.c. 



5$ carbolic acid solution in water 27 c.c. 



3. Ehrlich's anilin-gentian- violet : 



Saturated alcoholic solution of gentian-violet 7.5 c.c. 



Anilin-water 22.5 c.c. 



This stain requires occasional filtering and is somewhat 

 unstable. 



4. Gram's iodin solution: 



lodin o.i g. 



Potassium iodid 0.2 g. 



Dissolve in about 2 c.c. of water, and then add enough 

 water to make the total measure 30 c.c. 



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