18 GENERAL BACTERIOLOGY LESSON 



Solutions required : 



(a) Aniline Gentian-Violet is prepared in the following 

 manner : 



(a) First make aniline water by shaking up 4 cc. of aniline 

 oil with 100 cc. of distilled water for one to two minutes. 



(b) Filter the resulting emulsion through filter -paper 



moistened with distilled water. 



(c) To 100 cc. of aniline water add 11 cc. of a concen- 

 trated alcoholic solution of gentian-violet. 



Shake the mixture thoroughly and always filter it before use. 



This solution does not keep well, and should therefore 

 be prepared in small quantities. 



(/3) Gram's Iodine Solution : 



Iodine crystals . . .1 gramme 



Potassium iodide . . .2 grammes 



Distilled water . . 300 cc. 



(j) Absolute Alcohol. 

 Method of staining : 



(a) Prepare the hanging drop culture of the Streptococcus, 

 as described before for Bacillus filamentosus, and when the 

 film is dry and has been passed through the flame, place it 

 first in alcohol for one to two minutes. 



(b) Without drying it, transfer it to the aniline gentian- 

 violet, and leave it in the stain for half a minute to one 

 minute. 



(c) Soak up the superfluous stain with blotting-paper. 



(d) Now place it in Gram's solution of iodine for half a 

 minute to one minute. 



