Hoffman's violet may be as the formula above, or a structure very closely related, as it appears that the name is loosely applied. Some samples labeled as Hoffman's violet or dahlia may be methyl violets, or mixtures of these with pararosanilin. For that reason, the colour varies from red-violet to blue-violet. It has been recommended as a metachromatic dye, particularly for amyloid. The substitutes supplied under this name are usually as effective for this.
R. D. Lillie.
Conn's Biological Stains
Williams & Wilkins, Baltimore, MD., U.S.A.