MICROSCOPIC TECHNIQUE. 157 



Mix, shake vigorously, filter; the fluid after filtration should be 

 perfectly clear; add 



Alcohol 10 cc. 



Alcoholic solution of gentian-violet 11 cc. 



This solution should be freshly prepared about every two weeks. 



(8) LOFFLER'S MORDANT FOR FLAGELLA. 



Tannic acid 2 grams 



Water 8 cc. 



Saturated solution of ferrous sulphate 5 cc. 



Saturated alcoholic solution of fuchsin 1 cc. 



(9) ANILINE-WATER DYE FOR STAINING SPORES. 



Saturated alcoholic solution of fuchsin or 



gentian-violet < 11 parts 



Aniline oil water 100 parts 



Abs. alcohol 10 parts 



Keeps well for ten days. 



(10) AQUEOUS STAINS. 



Saturated aqueous solutions of fuchsin, gentian- violet, and 

 methyline blue will be found useful for all simple staining. 



(11) ALCOHOLIC SOLUTIONS. 



Saturated alcoholic solutions of fuchsin, gentian-violet, and 

 methyline blue should be kept on hand to be used in simple staining 

 and in connection with other stains. 



II. STAINING METHODS, 



(1) SIMPLE STAINING. 



This consists in using a single stain. The process is given on 

 page 27, method No. 10. 



(2) DOUBLE STAINING. 



This consists in using two stains, one to stain spores, protoplasm, 

 etc., and the other as a ground stain. The following methods will 

 illustrate double staining: 



