iv GRAM'S METHOD 19 



(e) Soak up the superfluous iodine solution, and gently 

 wash in absolute alcohol, until no more stain comes away. 



(/) Quickly wash the alcohol off in water, and dry the 

 film between folds of blotting-paper. 



(g) When the cover-glass is quite dry, mount it in xylol 

 balsam. 



Examine with a high power, and then with -^ in. oil 

 immersion : long chains of Streptococci will be 

 seen, stained dark violet. 



Prepare Cover-glass Films of a Liquefied Culture of Sta- 

 phylococcus Pyogenes Aureus, and Stain by Gram's 

 Method. 



(a) Prepare the film and pass it through acetic acid in 

 the usual manner (vide p. 9). 



(&) Wash off the acetic acid with water, dry the film 

 and pass it three times through the flame. 



(c) Now place the film in absolute alcohol for one to 

 two minutes, ano! stain with aniline gentian -violet, and 

 continue as above with Gram's solution, alcohol, etc. 



Staining of Pus 



(1 ) With methylene-llue. 

 {2) By Gram's method. 



(a) With a platinum loop smear a thin film of pus on 

 two clean cover-glasses. 



(b) Allow the films to dry in the air, and then pa^them 

 three times through the flame, keeping the smeared surface 

 upwards. 



