INVESTIGATION OF AMERICAN STAINS 143 



For the present series of tests, samples of the following were 

 collected: Methj'l violet, methyl violet B, methyl violet 2B, 

 methyl violet BS, methyl violet OB, crystal violet, and gentian 

 violet. There were over thirty samples in the entire lot, too 

 many, it was felt, to send to any one investigator for the first 

 test. Accordhigly a more or less indiscriminate selection was 

 made, so that each investigator had about twelve samples to 

 test, generally one or two of each type of dye. They were 

 asked to use the samples for the Gram stain, each man to employ 

 his own technic, but to give the exact procedure used. As it 

 turned out, scarcely any two men used the same technic, so the 

 results varied greatly. The plan is to run another test with a 

 standard technic. At present so few men have reported on any 

 one sample of dye and such various technics were used that the 

 results are not regarded as having more than a general signifi- 

 cance. It would not be fair to judge the individual samples 

 on the basis of this preliminary work ; so in this report the names 

 of the manufacturers and distributors are not given. Each 

 sample is denoted by number alone, each number indicating a 

 certain business house. Results are given in table 5. 



It was not expected when the work was started that the com- 

 pounds of lower methylation would prove satisfactory for the 

 Gram stain. It was somewhat of a surprise, therefore, to find 

 that out of 84 tests of individual samples of methyl violet, 

 methyl violet B and methyl violet 2B, there were 28 reports of 

 good results, and one report of excellent results. Nevertheless, 

 out of these same 84 tests, there were 36 reports of unsatisfactory 

 findings, such a high percentage in comparison with the residts 

 obtained with the higher methylated compounds that no further 

 work is to be done with these dyes. 



The dyes called aniUn violet, methyl violet BS, methyl violet 

 6B, and crystal violet, give in general as good results as "gentian 

 violet" and sometimes better. There is some variation, however, 

 in the products of different manufacturers, but on the basis of 

 these few tests, none can be condemned. According to present 

 indications, crystal violet can be substituted very successfully 

 for gentian violet in the Gram stain. Some manufacturers at 



