M 2265 (OTTO) Methyl Violet, indicator Cas no 8004-87-3 - used at a pH between 0 and 1.6. The dye has displayed strong staining of the internal limiting membrane of the eye. At a concentration of 4.0 x 10-5 mol L-1 Methyl violet 2B and pH 6.5 the dye has displayed a strong cytotoxic interaction with calf thymus DNA resulting in massive aggregates forming and conformational changes in calf thymus DNA. Methyl violet 2B has also been observed to quench the fluorescence of BSA.