LESSON ii STAINING WITH SIMPLE ANILINE DYES 9 



Staining of Micro-organisms with Simple Basic 

 Aniline Dyes 



Examine the same organisms after staining with ordinary 

 aniline dyes. 



Prepare staining solutions 



(1) To a watch-glass containing distilled water add 

 two to three drops of a filtered concentrated 

 alcoholic solution of fuchsine. 



(2) To a watch-glass containing distilled water add two 

 to three drops of a filtered concentrated alcoholic 

 solution of gentian-violet. 



(3) Into a watch-glass filter a little concentrated 

 aqueous solution of methylene-blue. 



(a) Clean cover-glasses as before and transfer a drop of 

 the broth culture to the centre of the cover-glass, and with 

 the platinum needle spread it uniformly over the surface. 



(I) Allow the film to dry in the air, covering it up with 

 a watch-glass so as to protect it from the dust. 



(c) When dry, pass the cover-glass three times through 

 the flame, holding it in a pair of forceps with the smeared 

 surface upwards. 



(d) Now place it in a solution of 20 per cent acetic 

 acid for five to ten minutes, by which means the ground 

 substance is removed and cleared up. 



(e) Wash the acetic acid off with distilled water, and 

 dry the cover-glass between folds of filter-paper. 1 



1 It is not always necessary to clear the ground substance with 

 acetic acid. 



