On Thu, 27 Apr 2000 RSRICHMOND@aol.com wrote:

> Tellyesniczky's fixative (boy, do I love copy-and-paste) appears to be
>one of
> many fixatives, published and proprietary, of approximately this
>composition.
> As I've posted before, I use Davidson's fixative (3 parts water, 3 parts
> waste ethanol, 2 parts 37% formaldehyde, 1 part glacial acetic acid) for
>such
> purposes.

  But Bob, are they really equivalent? The major differences among these
  AFA mixtures are in the amounts of water and alcohol. There's always
  enough acetic acid to give a clean chromatin appearance, and enough
  formaldehyde to immobilize the proteins (if it's given enough time).
  Most AFA fixatives contain somewhere around 75-85% alcohol and about
  20% water, by volume. Davidson's is more than half water, and only
  about 30-35% alcohol. This alcohol concentration is not high enough to
  bring about rapid coagulant fixation of all proteins. Gin, whisky etc
  all contain 40%, and they don't kill off the gustatory receptors.
  A professional taster, with his notebook and spitoon, exposes his
  tongue to something comparable to Davidson's (without formalin and
  acetic acid) for several hours every day.

                                     John Kiernan
                                     London, Canada.