MICROSCOPIC STUDY AND STAINING 107 



Stain in dilute alcoholic fuchsin for five minutes. 



Decolorize for twenty seconds in alcohol, ninety-five per cent, ten 

 parts, nitric acid one part. 



Wash in water. 



Counterstain in methylene-blue. 



Wash in water, dry, and mount. 



The tubercle bacillus should be blue and the bacillus of leprosy red. 



Special Stains for Polar Bodies.— These staining methods are designed 

 to bring into view polar bodies as found, for instance, in the bacilli of 

 diphtheria and plague. 



Neisser's Method.' — Smear and fix in the usual manner. 



Stain for two to five seconds in the following solution: 



Methylene-blue 1 gm. 



Absolute alcohol 20 c.c. 



Glacial acetic acid SO c.c. 



Distilled water 1,000 c.c. 



Wash in water. 



Counterstain in two per cent aqueous Bismarck brown solution for 

 five seconds. 



B}' this method polar bodies are stained blue, while the bacillary 

 bodies are stained brown. 



Roux's Method.^ — Two solutions are necessary. 



(1) Dahlia violet 1 gm. 



Alcohol 90 per cent 10 c.c. 



Aqua destUlata ad 100 c.c. 



(2) Methyl-green 1 gm. 



Alcohol 90 per cent 10 c.c. 



Aqua destillata ad 100 c.c. 



Before use, one part of solution No. 1 is mixed with three parts of 

 solution No. 2. The preparation is stained with the mixture for two 

 minutes in the cold. 



Polychrome Stains. — The various polychrome stains are of value to 

 the bacteriologist chiefly for the staining of pus and exudates where the 

 relation of bacteria to cellular elements is to be demonstrated. They 

 are also extremely useful in the study of fixed specimens of protozoan 

 parasites. There is a large number of these stains in use; a few only. 



1 Ndsser, Zeit. f. Hyg., xxiv, 1897. 



2 Roux and Yersin, Aonal. de I'inst. Past., 1890. 



