Re: Reference for this nerve stain???
I've not seen this one specifically, but it looks like
one of the "home made protargol" publications of the
1940s and 1950s. For example: Davenport HA, Porter RW,
Myhre BA (1952) Preparation and testing of silver-protein
compounds. Stain Technology 27: 243-248. In this paper,
the "best" silver protein was made from silver nitrate
and peptone. [For what it's worth, I tried their method
many years ago and couldn't get it to work.]
The expected effects of adding gelatin or other protein
to a dilute silver nitrate solution are (1) to lower the
concentration of sliver ions, by complexation, and
(2) possibly to retard the action of the developer - the
quick dip in water at Step 3 is probably a critical
one, allowing a small amount of the silver solution to
be carried over into the sulphite-hydroquinone.
Gelatin was used in one of GJ Romanes' earlier silver
methods for axons (J Anat 80:205-206, 1946). This was
in an ammoniacal solution containing tannic acid; it's not
the same as his better known 1950 method, which uses a
silver solution with a more studied composition, without
any "natural" ingredients (J Anat 84:104-115).
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London, Canada N6A 5C1
> Tony Henwood wrote:
> GELATINE SILVER FOR NERVE FIBRES
> Nerve fibres and axons have the ability to absorb silver ions
> that are then reduced by hydroquinone. The fibres are further
> darkened by oxalic acid. Selectivity is improved by including
> gelatine in the silver solution.
> Fixation: 10% buffered formalin.
> Microtomy: Paraffin sections at 5um.
> 1. Impregnating solution - prepare just prior to use:
> Distilled water 50ml
> Silver Nitrate 0.1g
> Gelatine 0.4g
> Place at 60oC for 15 minutes, mixing twice.
> 2. Reducing solution:
> Distilled water 50ml
> Sodium Sulphite 0.5g
> Hydroquinone 0.1g
> Mix, stand for 20 minutes before use.
> 3. 0.2% Gold Chloride
> 4. 2% Oxalic acid
> 5. 2% Sodium Thiosulphate.
> 1. Dewax and hydrate sections to distilled water.
> 2. Place in impregnating solution, 5 hours - overnight
> 3. Dip slide in distilled water once.
> 4. Place in reducing solution, 2 hours.
> 5. Running water, 10 minutes.
> 6. Distilled water, 1 minute.
> 7. Gold Chloride, 5 minutes.
> 8. Distilled water, 1 minute.
> 9. 2% Oxalic Acid, 2 minutes or longer.
> 10. Running water.
> 11. 2% Sodium Thiosulphate, 5 minutes.
> 12. Wash in water, 5 minutes.
> 13. Dehydrate, clear and mount.
> Axons and nerve fibres black
> Nuclei shades of grey
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