Re: Picric Acid Perspective
|From:||"Monson, Frederick C." |
For those who know my history, beware. This offering will degenerate into
merely another opportunity to practice with one of my pet peeves.
P. Gray, in Microtomist's Formulary and Guide(1954)
Picric Acid (Indexed locations in text) - Almost one full, 2-column
page(~1%) of Index (pp689-794)
Maceration and Decal - 8 refs
Stain - 1
Fixative Combos - 30
Differentiating - 3
Staining - 96
Removal - 2
Picro-carmines - 3
That suggests the pattern of picric acid use prior to the 1950's.
My initial exposure to this substance in the late '50's was with Bouin's.
In the early 90's, I possessed a jar of the stuff that I had owned for many
years - my usage was low. I had replaced the metal cap with plastic when I
took possession and I had always covered the crystals with pure water to
volume - as I had been taught.
What I acquired in the early '70's I finally disposed of in the late '90's,
because I had found it's value to have been overstated (for my purposes) in
the years before formaldehyde generated from paraformaldehyde became
available to all. [Note the not so subtle but still devious entree to his
WARNING TO READER!!!! Peeves of others can be hazardous to your health and
preconceptions. If such is the case, please...
NOTE1: In Fieser and Fieser (1967), Reagents for Organic Synthesis, p401, a
synthesis of a cortisone derivative(1964) is noted to have been improved (
to avoid side-reactions with the METHANOL in commercial "formalin") by
substituting paraformaldehyde for 30% formalin. The organic chemists appear
to have found paraformaldehyde as a "better" SOURCE of fresh, unadulterated
FORMALDEHYDE in the mid-sixties, about the same time as the electron
microscopists (see Pease, 1964 and compare with Pease (1960) where
paraformaldehyde was NOT mentioned). This unusual convergence of organic
chemistry and biology may well have occurred within the synthetic arm of the
pharmaceutical industry where the biologists may have 'discovered' the
existence of paraformaldehyde as a SOURCE of PURE formaldehyde NOT as a
substitute for fixation by formalin. That is, the early users of
paraformaldehyde apparently KNEW that one did NOT fix with IT but rather
with its MONOMER formaldehyde, which they generated FROM paraformaldehyde by
subjecting aqueous suspensions OF paraformaldehyde to (depolymerizing) heat
(~60 degrees C).
NOTE2: In the early 1970's, a well-known pharmacologist in a Philadelphia
medical school added an Organic Chemistry component to his Pharmacology
course so that the NEW breed of medical student might know enough organic
chemistry to understand HIS subject. Perhaps this should have warned me to
seek help for what has become a PEEVE of gargantuan proportions.
Admittedly, I have been told that a periodic DUMP of the anxiety caused by
this PEEVE is therapeutic for all but those behind the truck. Thus this
note ends with a general apology to those who did not exercise good
judgement and follow the GOTO command given prior to these two NOTES.
Parenthetic attack of Peevishness dispelled, thank you for your time and
Regards to all,
Frederick C. Monson, PhD
Center for Advanced Scientific Imaging
Schmucker II Science Center
West Chester University
South Church Street
West Chester, Pennsylvania, USA, 19383
CASI URL: http://darwin/wcupa.edu/casi/
WCUPA URL: http://www.wcupa.edu/
Visitors URL: http://www.wcupa.edu/_visitors/
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