Dear Bryan,

  This is one I haven't come across before. Have you got a
  reference for it, or is it a Llewellyn original? Also, what colour
  are the mast cells, blue or metachromatic? Is it an unremovable
  stain like aldehyde-fuchsine, which resists acid-alcohol - so that
  you can do it first and then follow up with other methods that
  would remove an ordinary basic dye? Lotsa questions. No hurry,
  but I'm interested because mast cells in skin & lung, and also in
  the brains of a few species (notably the hedgehog) were my
  major source of research grant money in the 1970s and '80s.
 
  My only Letter to Nature was reporting the mast cells in the
  hedgehog's thalamus and epithalamus, back in 1966. (As always
  it wasn't really a First.  A Dane called Krabbe had mentioned the
  epithalamic ones in the reported discussion of someone else's
  paper at some obscure meeting in, I think, 1928. As one of my
  mentors told me, "It's all been done before if you look in the
  literature.")  

  Perhaps Ald-Tol-Blu is in your StainsFile web page, and I've not
  spotted it yet. The "pick a letter" method of looking things up
  doesn't let you browse easily, as through a contents list or
  an index.

  Got back a couple of weeks ago from U.K. Lousy weather all
  August there, but saw old friends, married daughter (she came to
  Canada with us when she was 4 and re-immigrated, or should it
  be de-emigrated?) and various of my wife's relatives (the funeral
  of a very old one brought many together unexpectedly). 

  You have mentioned poor health in earlier emails, and I sincerely
  hope that it's got a bit richer and that all's well with you in B.C.

  Best regards, 
                                          John.    

At 01:50 PM 9/13/99 -0700, Bryan Llewellyn wrote:

>I use aldehyde-toluidine blue.  Make it the same as aldehyde fuchsin, just
>use toluidine blue instead of basic fuchsin.  Ripen it for about a week at
>room temperature.  It is stable for a very long time if used for mast cells.
>I have noted that the sample of toluidine blue does make a difference.  The
>best seems to be from Fisher Scientific.  You may need to try several
>others.  When you find one, keep lots.
__________________________________________

                    John A. Kiernan
                    Dept of Anatomy and Cell Biology
                    University of Western Ontario
                    LONDON,   Canada.
 
                      (kiernan@uwo.ca)