Re: staining (acid-alcohol after haemalum)

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From:"J. A. Kiernan" <>
Date:Tue, 28 Sep 1999 11:40:28 -0400 (EDT)
Content-Type:TEXT/PLAIN; charset=US-ASCII

On Tue, 28 Sep 1999 Edna_J_Gonzalez/ wrote:

> in running tap water, I dip the slides two times in 1% HCl in 70% ethanol.
> At this point the slides will turn light red or pink, but now they are not
> turning to light red, they stay purple. 

   This means that either (a) your acid-alcohol is not acidic
   enough, or (b) 2 dips is not enough to allow the acid-
   alcohol to permeate the sections, change the colour, and 
   extract some of the alum-haematein. If your acid-alcohol
   was freshly made from 70% (or 95%) alcohol and concentrated
   hydrochloric acid explanation (a) is unlikely, so the first
   thing to try is a few more dips in the acid-alcohol. You
   should see some colour (red) being extracted. Then wash
   in tap water (made slightly alkaline if necessary, to
   change the alum-haematein colour to blue), and check with
   a microscope to see if you have a pure nuclear stain. If it
   is overstained, repeat the acid-alcohol treatment. If you
   have extracted too much, go back to the alum-haematein and
   try again.

   Many people prefer a progressive nuclear staining, controlled
   by the time in alum-haematoxylin, so that there is then no
   need to overstain and remove the excess with acid-alcohol.

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

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