STAINING AND MODIFICATIONS. 41 



Flagella Stain, with Loffler's Mordant. I. A few drops of the 

 mordant (No. viii. p. 33) are placed upon the spread cover-glass 

 and heated until it steams. 



II. Washed with water until the cover-glass looks almost clean, 

 using a small piece of filter paper to rub off the crusts which have: 

 gathered around the edges. 



III. Anilin water fuchsin (neutral) held in flame about 1| 

 minutes. 



IV. Wash in water. 



If the stain is properly made, the microbes are deeply colored 

 and the flagella seen as little dark lines attached to them. 



Sporogenic bodies stain quite readily, and in order to distin- 

 guish them from spores Ernst uses alkaline methylin blue, slightly 

 warmed. Then rinse in water. Contrast with cold bifemark- 

 brown. 



The spores are colored bright blue, the spore granules a dirty 

 blue, being mixed with the brown, which colors also the bacteria. 



Kuhne's Method. In sections, the alcohol used sometimes de- 

 colorizes too much. To obviate this Kiflme mixes the alcohol 

 with the stain, so that while the section is being anhydrated it 

 is constantly supplied with fresh dye. 



Weigert uses aniline oil to dehydrate instead of alcohol, and 

 here, too, it can be used mixed with the dye. 



Unna's Method for Fungi (especially useful for epidermic; 

 scales). Moisten horny scale or crust with acetic acid; mace- 

 rate between two glass slides ; dry in flame ; wash out fat with, 

 ether and alcohol (equal parts) ; stain in borax methyl blue for 

 ten seconds (over flame) ; bleach with glycerine and aether (equal 

 parts) ; rinse in water, alcohol, dry, and mount. 



Behavior of the More Important Bacteria to Gram's Stain. 



Positive means that the bacteria retain the primary color, or 

 gentian violet. 



Positive. Negative. 



Tubercle Bacillus, Colon Bacillus, 



Smegma Bacillus, Typhoid Bacillus, 



Lepra Bacillus, Cholera Bacillus, 



Anthrax Bacillus, Influenza Bacillus, 



