Staining 453 



Saturated alcoholic solution of methylene-blue . . 30 

 1 : 10,000 aqueous solution of caustic potash . . 100 



Emery prefers Hanson's borax methylene-blue. A stock 

 solution which keeps well is prepared by dissolving 2 grams 

 of methylene-blue and 5 grams of borax in 100 c.c. of water. 

 This is diluted with from five to ten times its volume of 

 water for ordinary use. An aqueous solution of dahlia 

 is recommended by Roux. 



The Neisser method of staining the diphtheria bacillus, 

 which met with a very cordial reception, is as follows: 



The prepared cover-glass is immersed for from two to 

 three seconds in 



Alcohol (96 per cent.) 20 parts 



Methylene-blue 1 part 



Distilled water 950 parts 



Acetic acid (glacial) 50 " 



Then for three to five seconds in 



Bismarck brown 1 part 



Boiling distilled water 500 parts 



The true diphtheria bacilli appear brown, with a dark blue 

 body at one or both ends; the pseudo-diphtheria .bacilli 

 usually exhibit no polar bodies. 



Park * in his large experience found that neither the 

 Neisser nor the Roux stain gave any more information 

 concerning the virulence of the bacilli than the Loffler 

 alkaline methylene-blue. 



When cover-glass preparations are stained with these 

 solutions, the bizarre forms already mentioned are par- 

 ticularly obvious, and the contrast between the polar 

 granules, which color intensely, and the cytoplasm of the 

 bacillus, which tinges slightly, is marked. Through good 

 lenses the organisms are always distinct bacilli, notwith- 

 standing the fact that the ends stain more deeply than the 

 centers, and it is only through poor lenses that the organ- 

 isms can be mistaken for diplococci. 



The bacilli stain well by Gram's method, which is ex- 

 cellent for their definition in sections of tissue, though 



* "Bacteriology in Medicine and Surgery," 1900. 



