One thing that can spoil the Schiff reaction (Feulgen or PAS; bought
 or home-made reagent) is too low a temperature. It is usual, but not
 necessary, to store Schiff's reagent in the fridge. If you do this,
 you must let it warm to room temperature before using it. It is
 unlikely that Schiff bought from any supplier will be no good. The
 only way it can go off is by losing sulphur dioxide (loose bottle
 cap). The colour then changes to pink. A yellow discoloration in
 home-made Schiff is harmless but can be removed with activated
 charcoal.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1
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On Mon, 17 Jul 2000 CMCCOLLOUGH@dnr.state.md.us wrote:

> I am tearing my hair out.  I have attempted to make Schiff's that will work
> in the Feulgen reaction (a routine stain in our lab) using 4 different lots
> of dry stain and 3 different recipes (Lilllie's cold, Coleman's hot, and
> Bancroft & Stevens), all to no avail.  Previously wonderful ready-made stain
> from our usual supplier no longer works (have tried 4 or 5 different lots).
> This supplier has recently changed lots of dry stain as well.  I have tried
> a second ready made stain to no avail.  All work fine in the PAS stain, but
> not Feulgen.
> 
> Is there a vendor who can supply me with a Schiff's tested for Feulgen?
> 
> Comments from John Kiernan, Samurai, and other Histonet gurus are most
> welcome.
> 
> Regards -
> Carol
> *****************
> Carol B. McCollough, HT(ASCP)
> Diagnostics & Histology Laboratory Manager
> Maryland Department of Natural Resources
> Fisheries Service
> Cooperative Oxford Laboratory
> 904 S. Morris Street
> Oxford, MD 21654
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