[Histonet] Missing procedure for silver preparations

[George Cole]

PARDON PARDON PARDON
 
I left out a page of the Nerve and Muscle procedures when I sent them
out. It is a method that keeps the nerve tissue sections on the slide
during silver impregnations. Silver nitrate is notorious for loosening
sections on a slide.
 
The preparation uses Claoue's Cement--- adapted from a process in The
Microtomist's Formulary and Guide by Peter Gray, from the Blakiston
Co.inc
 
It's main ingredient:   Collodion---Mallinkrodt order number UN 1993
 
FORMULA:
Claoue's Cement:
Collodion                   8 ml
100% Ethyl Alcohol  92 ml
Camphor                   2 gm
Castor Oil                  3 ml
 
PROCEDURE:
 
I usually mixed 2 or 3 times the above amounts to make 200 or 300 ml of
Claoue's. Kept tightly closed, it keeps for a long time.
I know this looks like snake oil, but it works.  Regular pyroxylin or
celloidin solutions in alcohol and ether alone, can form a kind of sheet
which can peel off taking the tissues with it.  This prep forms an
emulsion which keeps the tissues on the slides very nicely.
 
Paraffin Sections:  Remove paraffin as usual.  After the last 95%
alcohol, remove one or two slides from the alcohol to put on a clean
paper towel. Place two or three sheets of bibulous paper very carefully
on the slides.  Blot gently with two or three fingers   
for two or three strokes from one end of the slide to the other.
Carefully turn the bibulous paper over and repeat the blotting as
before. This smoothes wrinkles and fixes the tissue to the slide. With
an eye dropper, apply enough drops of Claoue's to cover the sections and
to the edge of the slide where the sections are. Drain any surplus
Claoue's off by touching both edges of the slides to the bibulous paper.
Blow gently on the slides until the Claoue's turns opaque. Rinse in two
changes of 95% ethyl alcohol and proceed with what ever stain you are
doing. This preparation is compatible with silver impregnations and the
Kluver-Berrera beautiful luxol fast blue and cresyl fast violet---and
many others.
 
When the silver impregnation is done, the slides are run up the
alcohols. In the first two 100% alcohols, the Claoue's coating will come
off with some silver giving it color. After two more 100% alcohols,
clear and cover as usual. Be careful in these final stages.  With the
Claoue's covering removed, the sections may loosen if handled roughly.
I say this, although I have never lost a section at this time in the
procedure.  But I'm always careful there anyway.
 
Good luck with your silver preps.        
 
   
 
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