Thionin is a strongly metachromatic dye, useful for the staining of acid mucopolysaccharides. It is also a common nuclear stain and can be used for the demonstration of Nissl substance in nerve cells of the CNS. Compare its formula to those of the other metachromatic thiazin dyes.
There is, apparently, another dye named thionin blue (CI 52025) which is very occasionally confused with thionin, but which cannot be substituted for it.
R. D. Lillie.
Conn's Biological Stains
Williams & Wilkins, Baltimore, MD., U.S.A.
Susan Budavari, Editor, (1996)
The Merck Index, Ed. 12
Merck & Co., Inc., Whitehouse Station, NJ, USA
Edward Gurr, (1971)
Synthetic dyes in biology, medicine and chemistry
Academic Press, London, England.
Aldrich chemical catalogue, 1992
Aldrich Chemical Company, Milwaukee, WI, USA.