METHODS OF OBSERVING BACTERIA. 157 



methylated spirit, then washed in water and counter- 

 stained with saturated aqueous methylen blue for half a 

 minute, washed with water, dried, and mounted in 

 Canada balsam. 



Moller ' finds it decidedly advantageous to prepare the 

 films, before staining, by immersion in chloroform for 

 two minutes, following this by immersion in 5 per cent, 

 chromic acid solution for one-half to two minutes. 



Anjeszky 2 recommends the following method of stain- 

 ing spores which is said to always give good results even 

 with anthrax bacilli : A cover-glass is thinly spread with 

 the spore-containing fluid and dried. While it is drying 

 some y 2 per cent, hydrochloric acid is warmed in a por- 

 celain dish over a Bunsen flame until it steams well and 

 bubbles begin to form. When the solution is hot and 

 the smear dry, the cover-glass is dropped upon the 

 fluid, which is allowed to act upon the unfixed smear for 

 three to four minutes. The cover is now removed, 

 washed with water, dried, and fixed for the first time, 

 then stained with Ziehl's carbol-fuchsin solution, which 

 is warmed twice until fumes arise. The stain is allowed 

 to cool, decolorized with 4-5 per cent, sulphuric acid 

 solution, and counterstained for a minute or two with 

 malachite green or methylen blue. The whole pro- 

 cedure should not take longer than eight to ten minutes. 



Fiocca 3 suggests the following rapid method : ''About 

 20 c.cm. of a 10 per cent solution of ammonium are 

 poured into a watch-glass, and 10-20 drops of a saturated 

 solution of gentian violet, fuchsin, methyl blue, or saf- 

 ranin added. The solution is warmed until vapor begins 

 to rise, then is ready for use. A very thinly-spread cover- 

 glass, carefully dried and fixed, is immersed for three to 

 five minutes (sometimes ten to twenty minutes), washed 

 in water, washed momentarily in a 20 per cent, solution 

 of nitric or sulphuric acid, washed again in water, then 



1 Centralbl. f. Bakt. u. Parasitenk., Bd. x., p. 273. 



2 Ibid., Feb. 27, 1898, xxiii., No. 8, p. 329. 

 s Ibid., July I, 1893, x ' v -> No. '• 



