On Fri, 21 May 1999, Christine Lee wrote:

> I have been asked about the difference between Methylene Blue and New 
> Methylene Blue. I am not sure of the answer. Can anyone else answer this.

   Lots of people could, and probably will. They are completely
   different dyes, though both cationic and within the thiazine
   family. According to Conn's Biological Stains, 9th ed., NMB
   was passed off as MB in the early 1950s and may have been 
   better for some purposes, especially if a metachromatic
   stain was wanted, but worse for most others uses of MB.

   For a better answer, you'll  need to say what you expect of
   the dye. Histonetters will then answer in battalions.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1