MICLIO-ORGAKISMS. 75- 



STAINING COVER-GLASS PREPARATIONS. 



For micro-organisms (when special methods are not em- 

 ployed) the following plan may be adopted : 2 or 3 drops 

 of aqueous solution of either Fuchsine, Methylene Blue, 

 Methyl Violet, or Gentian Violet, are placed on the cover- 

 glass preparation ; after a couple of minutes the superfluous 

 stain is washed off with Distilled Water; the cover-glass 

 can now be examined if it be placed, preparation downwards, 

 on a glass slip, and the excess of Water removed with blot- 

 ting-paper, or if a permanent preparation be desired the 

 excess of Water is removed with blotting or filter paper, the 

 cover-glass is then allowed to dry, and finally mounted in 

 Balsam. 



In place of the above aqueous solutions, Vesuvine dissolved 

 in Glycerine (p. 57) may be used, the film is then washed and 

 mounted in undiluted Glycerine. 



Cover-glass preparations may also be treated by any of the- 

 methods described for use with sections. 



STAINING TUBERCULAR SPUTUM. 



A cover-glass preparation of sputum (p. 74) is placed in Car- 

 bolic Fuchsine (p. 59) warmed in a watchglass until steam rises 

 for 3 minutes ; it is then rinsed in Water to remove the ad- 

 hering stain, decolourised in Nitric Acid (p. 62) (preferably 

 Sulphanilic Nitric Acid), washed in 90 p. c. Alcohol to re- 

 move the Acid, then placed in aqueous solution of Methylene 

 Blue (p. 36) for 1 minute, and well washed in Water to 

 remove excess of stain; dried and mounted in Benzol 

 Balsam. 



If there be an objection to the use of Nitric Acid, then 

 Sulphuric Acid and Alcohol (p. 62) may be used as a sub- 

 stitute. 



