Chapter XV: Bacteria 109 



methyl violet, gentian violet, or fuchsin (basic) and, if desired, counter- 

 stain lightly with Bismarck brown; examine in water or dehydrate in 

 absolute alcohol, clear in xylol and mount in balsam. 



To demonstrate bacteria in tissues, a mouse may be inoculated with 

 anthrax, and paraffin sections of the spleen prepared. Stain by the 

 gentian violet method. 



3. Some of the Most Important Stains for Bacteria are as follows: 

 a) Anilin water solution of gentian violet (Koch-Ehrlich's). 



Gentian violet, saturated alcoholic solution ... 10 c.c. 

 Anilin water (see Appendix B, reagent 29) . . . 100 c.c. 



After shaking it, the mixture should be set aside for 24 hours because of 

 the precipitation which takes place soon after making. Solutions of 

 fuchsin (basic) and methyl blue are made in the same way. These solu- 

 tions begin to decompose after about 10 days and must then be freshly 

 prepared. They yield good results with many species of bacteria. The 

 gentian violet, particularly, is widely used in connection with Gram's 

 method (see /). 



6) Alkaline methylen blue (Loeffler's). 



Methylen blue, saturated alcoholic solution . . 30 c.c. 

 Caustic potash, aqueous solution (1: 10,000). . . 100 c.c. 



This stain keeps well and is one of the most widely used of the general 

 stains. It is especially serviceable in staining the bacillus of diphtheria 

 or of glanders. 



c) Carbol-fuchsin (Ziehl-Neelson's). 



Fuchsin, saturated alcoholic solution 10 c.c. 



Carbolic acid, 5 per cent, aqueous solution ... 90 c.c. 



This stain keeps well, stains powerfully, and can be used on many forms 

 of bacteria. 



d) Neisser's method for the diagnosis of Diphtheria. 



Solution I. 



Methylen blue (Grtlbler's) 1 gram 



Alcohol, 96 per cent 20 c.c. 



Distilled water (add after the methylen blue has 



dissolved in the alcohol) 950 c.c. 



Glacial acetic acid 50 c.c. 



Solution II. 



Bismarck brown 1 gram 



Distilled water (should be boiling when the Bis- 

 marck brown is added) 500 c.c. 



Cover-glass preparations are stained for from 2 to 3 seconds in Solution 

 I, rinsed in distilled water, placed in Solution II for from 3 to 5 seconds, 



