Gentian Violet

Gentian Violet (генцианвиолет), a basic triphenylmethane dye of purple color, used in microscopy, especially in bacteriological techniques (Weigert and Ehrlich, 1881-82). Chemically, it is a heterogeneous product, mostly a mixture of 3-, 5-, and 6-methylpararosanilins. The commercial product usually contains an admixture of fuchsin and dextrin. Preparation: 1) 11 cubic centimeters of concentrated (95°) alcoholic solution of G. is shaken with 100 cubic centimeters of aniline water (see) and filtered (Weigert, 1881); or-2) alcoholic solution of G. is added to aniline water until a film with a metallic luster forms on its surface (Gram, 1884); or-3) 10 cubic centimeters of saturated alcoholic solution of G. is mixed with 100 cubic centimeters of freshly prepared 1-2% carbolic water (Nicolle, 1895); or-4) excess G. is dissolved in a mixture of equal parts of aniline water, 5% carbolic water, and 100° alcohol. In bacteriology, Gentian violet is used for both direct staining and subsequent treatment with Lugol's solution in the so-called Gram method (see Gram method).