----- Original Message -----
From: "J. A. Kiernan" 
 There are plenty of old papers about
> iron-celestine blue B alone as a nuclear stain. Why
> is it advantageous to follow it up with a haemalum?
> --

When I was a student in paleolithic times in London, it was commonly
believed that the celestine blue-hemalum sequence was simply a fast and
convenient way to get an iron hematoxylin stain.  Celestine blue is made up
in iron alum and the iron attaches to chromatin.  The hematein in Mayer's or
Cole's hemalum then replaces the celestine blue.  The immediate question, if
that is so, is why use celestine blue, why not just use iron alum?  In fact,
this is how I have applied the stain for about 30 years.  It works quite
well.

Bryan Llewellyn