VI. STAINING METHODS. 



IN the following pages are collected the various 

 "stock" stains in everyday use in the bacteriological 

 laboratory, together with a selection of the most con- 

 venient and generally useful staining methods for 

 demonstrating particular structures or differentiating 

 groups of bacteria. The stains employed should either 

 be those prepared by Gruebler, of Leipzig, or Merck, of 

 Darmstadt. The methods printed in ordinary type 

 are those which a long experience has shown to be the 

 most reliable, and to give the best results those 

 relegated to small type comprise such as are not so 

 generally useful, but give excellent results in the hands 

 of the experienced worker. 



BACTERIA STAINS. 



Methylene-blue. 



1. Saturated Aqueous Solution. 

 Weigh out 



Methylene-blue 1.5 grammes 



Place in a stoppered bottle having a capacity of 

 from 150 to 200 c.c. and add 



Distilled water 100.0 c.c. 



Allow the water to remain in contact with the dye 

 for two weeks, shaking the contents of the bottle vig- 

 ourously for a few moments every day. Filter. 



2. Saturated Alcoholic Solution. 

 Weigh out 



Methylene-blue 1.5 grammes 



9 



