On Thu, 6 Jul 2000, Jim Darley wrote:

> Here is the note from our wholesaler/ manufacturer:
> 
> "Thank you for your E Mail concerning Alcian Blue 8GX. As per previous
> correspondence the problem is with us and will not disappear.
> The last 3 years we found some old ICI material (low dye content 10-20%), which 
> we upgraded. That has come to an end; no company in the world to our knowledge 
> is producing the material, textile quality or stains quality. ..."

> ... a 1996 CD ROM will not reveal anything that has happened during 
> the past three years.

  That's true; I don't have the 1999 version of the C.I. CD-ROM.
  However, on May 11th 1999 the Biol Stain Commission certified a 
  batch of alcian blue 8GX for the Aldrich Chemical Company. See
  Biotech. & Histochem. 74 (5) p. 274 (Sept 1999). So there must
  have been some new stuff around last year.

  Alcian blue 8GX (dye content approx 50%) is in the Sigma
  and Aldrich catalogues for 2000-2001; same price as
  haematoxylin. (Curiously, both dyes are about $10 cheaper for
  25 grams if you buy from Sigma rather than Aldrich. Strange,
  when they're the same company! In the Fluka catalogue for
  1999-2000 - also the same firm, I think - the prices of both
  dyes are some $20 higher than Aldrich's.) Aldrich also supply
  a "pyridine variant" of alcian blue, which is more expensive,
  and in the past they sold another variant called "alcec blue,"
  which could also be used for the same staining methods (see 
  F. Green 1991: The Sigma-Aldrich Handbook of Stains, Dyes and
  Indicators, p. 69-72).  

  A low dye content such as the 10-20% in your old ICI material
  is not necessarily a bad thing for alcian blue, and batches
  with high dye content (70% +) often perform badly. It seems
  likely that the additives (dextrin, boric acid etc) are
  needed in adequate amount.

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