Re: FW: Carnoy's (source of; why buy?)

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From:"J. A. Kiernan" <> (by way of histonet)
To:histonet <>
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On Tue, 10 Nov 1998, Luke, Don wrote:

> ... Who do you get the Carnoy's from? And, How much do you pay?  I
> found 2 vendors Poly Scientific $94.00/gal and EK Industries $24.00/gal.

  Why buy Carnoy's fluid ready-made? You can make
  your own as needed by mixing the three cheap
  ingredients. It takes less than 2 minutes, including
  putting away the stock bottles.

  If you do buy it ready made, it won't stay the same
  as the fresh stuff. The reversible reaction:

   acetic acid + ethanol  <---> ethyl acetate + water

  begins when the ingredients are mixed, and continues
  over several days (longer?) until an equilibrium
  mixture is attained. The fruity smell of ethyl
  acetate is quite evident in Carnoy kept for 24-48
  hours. I've never kept it for longer, and don't
  know the composition of the final mixture, or
  whether the chemical change makes any difference
  to the fixation. However, the only way to be
  sure you're using the same stuff every time is
  to make it up fresh.
    Interestingly, aged solutions of Gendre's "alcoholic
  Bouin" (alcohol, acetic, picric & formalin) are better
  than the freshly mixed fixative for some purposes.
  An artificially aged mixture is made by including
  25% ethyl acetate (Gregory RE 1980. Stain
  Technol. 55: 151-160).

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

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