The three formulae above reflect the difficulties associated with identifying dyes, At one time or another, according to Conn's Biological Stains, each of the above compounds have been manufactured under the name cresyl violet. Green gives a formula which is essentially the same as (a), and Edward Gurr gives a formula essentially the same as (b). The data panel to the left reflects that of Green, but Conn is much the same. The differences between Green and Gurr are likely a consequence of different samples of cresyl violet actually being different compounds.
This dye is often provided as cresyl violet acetate (CH3CO2–) and is sometimes specified that way.
Should a sample of this dye be unsatisfactory in use, it is worth while obtaining another sample, simply because its composition may vary. This is particularly so if the dyes being used are old stock.
Cresyl violet is most commonly used for the demonstration of Nissl bodies and nuclei. There is also a method for the demonstration of sex chromatin in buccal smears, which is very similar to one of the methods for Nissl bodies. It is a metachromatic dye but there appears to be little use made of that in practice.
Horobin, R. W. and Kiernan, J. A.
Conn's Biological Stains, ed. 10.
BIOS Scientific Publishers, Oxford, UK.
Floyd J. Green
Sigma-Aldrich handbook of stains, dyes and indicators, 1990
Aldrich Chemical Company Inc., Milwaukee, Wisconsin, USA.
Encyclopaedia of microscopic stains, 1960
Leonard Hill (Books) Ltd., London, UK.