Mark,
Air dry your mounted sections, dip them briefly (5 sec.) in dilute (1-3%)
gelatin solutions, air dry again, and dehydrate as usual.  We've done this
with sections as thick as 200 um (cut frozen on an prized A0 860 sliding
microtome/boat anchor, for those of you who have been following the
discussion of old histo hardware).  If you need them even more tightly
attached you can dip the air-dried gelatin-coated slides in a crosslinking
fixative (formaldehyde etc.).  The thin coating doesn't impair Nissl
staining either.  Happy histo,

Mark wrote on 23 Aug 2001 16:11:29 -0500:
From: millerm@brandeis.edu
Subject: folding mouse sections
I'm nissl staining thin (35-50 micron) mouse brain sections, and having
problems with the sections folding around the edges during the staining
procedure. They look fine when I slice them (on a cryostat) and mount
them on gelatin-subbed slides, but after processing they're folded and
some sections have come off the slides completely. I've noticed that
this happens more often in the EtOH steps than xylene steps, for what
that's worth. Any advice would be great. Thanks
mark