NEW METHOD FOR GRAM STAIN 1G3 



and ether (equal parts), otherwiHe following the method of 

 Jensen except that safranin was used as a counter stain. 



Briefl}^ Jensen's method is as follows: Air drj% fix with mild 

 heat, cool before flootling with 0.5 i)er cent methyl violet solution 

 for fifteen to thirty seconds; rinse off methyl violet with iodine 

 solution, flood with fresh iodine solution for thirty to sixty sec- 

 onds, drain off iodine solution and wash with absolute alcohol 

 until stain ceases to come out of film; counter stain for fifteen 

 to thirty seconds with neutral red made up as follows: 1 gram 

 neutral red, 2 cc. glacial acetic acid, 1000 cc. distilled water. 



With 95 ])er cent alcohol as the decolorizer only one of our dyes 

 gave satisfactory results. Using absolute alcohol four of the 

 dyes, three of the methyl violets and the crystal violet, gave 

 good differentiation. Better results were obtained with acetone 

 or acetone and ether than with absolute alcohol. These results 

 show that all American methyl violet dyes do not give satisfactory 

 results when used according to the method of Jensen. Of the 

 dyes used one of the methyl violet dyes gave distinctly superior 

 results and another distinctly inferior results. The crystal 

 violet dye gave better results than some of the methyl violet 

 and any of the gentian violet dyes used. 



The dyes were found to vary in the amount of precipitate 

 formed upon the addition of the iodine solution and the rapidity 

 with which this precipitate went into solution in the decolorizer. 

 The dye giving the poorest results produced a heavy precipitate 

 which went into solution slowly. This required longer exposure 

 to the decolorizer which partially accounts for the poor results. 

 One of the essentials of a good dye should be that the precipitate 

 formed with the iodine solution go into solution in the decolorizer 

 very rapidly. 



An attempt to modify the method of Jensen so that satisfac- 

 tory differentiation can be determined with a larger percentage 

 of American dye products was successful and is given in detail 

 at the end of the article.* We will discuss here only certain 



•• The methyl violet dye giving the best results, i.e., resisting decolorization 

 the longest, was a sample furnisherl by the Will Corporation of Rochester, New 

 York, and submitted to us as their methyl violet No. 3. With the method of 



