>----------------------------------------------------------------------
>
>Date: 16 Jun 1999 14:01:15 -0500
>From: "Barry Rittman" <brittman@mail.db.uth.tmc.edu>
>Subject: Re: celloidin sections
>
>Hedley,
>            positive things to remember about celloidin are that
>
>1. shrinkage and distortion is minimal compared to paraffin (approximately
>5%)
>
>2.    for most celloidin techniques no heat was involved and therfore
>tissues could be left infiltrating for extended periods of time (and this
>was usually a requirement)
>
>3. thick sections in the order of  100 microns or greater could be cut and
>provided valuable insight into the spatial organization of various tissues.
>With confocal and other types of microscopy it is possible to optically
>section these.
>
>4.    very large blocks of tissue could be processed
>
>I think that the abandonment of celloidin in favor of paraffin wax was
>inevitable due to the time required for processing of  blocks and the skill
>in producing and staining sections. However, I have not seen paraffin
>sections of eye that can equal celloidin sections as regards the lack of
>distortion and the clarity of staining and detail.
>Barry.
>
Barry

I agree with the comments made re celloidin processing, and the beauty
revealed using this method.

However, wax blocks of many sizes can be "back processed" and stained as
a whole. These are then viewed under stereo microscopes, giving a whole
new outlook on life. Try it with a "in situ" breast carcinoma.

Mail me your fax number, and I can give references if you wish. They are
few and far between.

Regards.
-- 
Hedley David Glencross