MICROSCOPIC STUDY AND STAINING 97 



through a moist filter paper until perfectly clear. A saturated alco- 

 holic solution of either fuchsin or gentian-violet is added to this anilin 

 water in proportions of about one to ten or until a sHghtly iridescent 

 pelhcle appears upon the surface of the solution. 



An extremely useful and very strong staining solution is the Ziehl 

 carbol-fuchsin solution, made up as follows : ' 



Fuchsin (basic) 1 gm. 



Alcohol (absolute) 10 c.c. 



Five per cent carbolic acid 100 c.c. 



To make up this staining solution, mix 90 c.c. of a five per cent aque- 

 ous solution of carbolic acid with 10 c.c. of saturated alcoholic basic 

 fuchsin. 



It may also be made up as follows: 



Weigh out 



Basic fuchsin 1 gram 



Carbolic acid 5 grams 



Dissolve in 



Distilled water 100 c.c. 



Filter and add 



Absolute alcohol 10 c.c. 



SPECIAL STAINING METHODS 



Spore Stains. — Abbott's Method.^ — Cover-slips are smeared and 

 fixed by heat in the usual manner. 



Cover with LoefHer's alkaline methylene-blue and heat the stain 

 until it boils, repeat the heating at intervals but do not boil continuously. 

 Keep this up for one minute. 



Rinse in water. 



Decolorize with a mixture of alcohol eighty per cent 98 c.c. and nitric 

 acid 2 c.c, until all blue has disappeared. 



Rinse in water. 



Dip from three to five seconds in saturated alcoholic solution of 

 eosin 10 c.c, and water 90 c.c. 



Rinse in water, blot, and mount in balsam. 



By this method the spores are stained blue, the bodies of the bacilli 

 are stained pink. 



» Ziehl, Deut. med. Woch., 1882. ' Abbott, "Prin. of Bact.," Phila., 1905. 



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