126 BIOLOGY AND TECHNIQUE 



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

 Hermann's Stain for Acid Fast Bacteria: 30 



I. Crystal Violet 3% in alcohol. 

 II. Ammonium Carbonate 1% aqueous. 



Mix one part of "I" with 3 parts of "II" just before using. Steam 

 3 minutes. Decolorize with 10% nitric acid (or 5% sulphuric acid). Wash 

 in alcohol, rinse and counterstain with Bismarck brown. The better contrast 

 obtained with this stain is stated by Park to increase the ease with which 

 tubercle bacilli can be found in sputum. 



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. 31 Smear and fix in the usual manner. 



Stain for two to five seconds in the following solution : 



Methylene-blue 1 gm. 



Absolute alcohol 1 20 c.c. 



Glacial acetic acid 50 c.c. 



Distilled water 1,000 c.c. 



Wash in water. 



Counterstain in 0.4 per cent aqueous Bismarck brown solution 

 for five seconds. 



By this method polar bodies are stained blue, while the bacillary 

 bodies are stained brown. 



Carbol Thionin: 



Saturated solution of thionin in 50% alcohol 10 c.c. 



2% aqueous solutions of phenol 100 c.c. 



Stain one to three minutes. 



See also Toluidin Blue solution given on page 115. 



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 demon- 

 strated. They are also extremely useful in the study of fixed speci- 

 mens of protozoan parasites. There is a large number of these 

 stains in use ; a few only, however, can be given here. In principle, 



80 Quoted from Park and Williams, Pathogenic Microorganisms, Lea and 

 Fcbiger, Phila., 1920. 



31 Neisser, Zeit, f, Hyg., xxiv, 1897. 



