Palmgren's Silver Impregnation
for Peripheral Nerves


Solution A
Concentrated formalin 25 mL
Nitric acid, 1% aqu. 0.2 mL
Distilled water 75 mL
Solution B
Silver nitrate 15 g
Potassium nitrate 10 g
Glycine, 5% aqu. 1 mL
Distilled water 100 mL
Solution C
Pyrogallol 5 g
Nitric acid, 1% aqu. 1 mL
Absolute ethanol 275 mL
Distilled water 225 mL
Solution D
Gold chloride 1 g
Acetic acid, glacial 0.2 mL
Distilled water 200 mL
Solution E
Aniline 4 drops
Ethanol, absolute 100 mL
Distilled water 100 mL
Solution F
Sodium thiosulphate 5 g
Distilled water 100 mL

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable.
Chrome, mercury and osmium fixatives should be avoided.


  1. Bring sections to water via xylene and ethanol.
  2. Celloidinise sections.
  3. Place into solution A for 15 minute at room temperature or for 5 minutes at 35°C.
  4. Rinse with distilled water, three times over 5 minutes.
  5. Do not rinse with water. Place into fresh solution C at 45°C for one minute. Agitate continuously.
  6. Rinse with 50% ethanol.
  7. Rinse thoroughly with distilled water, three times over 5 minutes.
  8. Optionally, tone with solution D to the colour wanted.
  9. Place into solution E for 15 seconds, agitating continuously.
  10. Rinse with tap water.
  11. Fix with solution F for 5 seconds.
  12. Rinse well with tap water.
  13. Dehydrate with ethanol, remove celloidin and clear with xylene. Mount with a resinous medium.

Expected results


  1. Toning with gold chloride (solution E) may be applied at step 8. Many workers find the black on grey scheme less satisfactory than dark brown on light brown.
  2. If the nerve fibres are poorly shown, the impregnation may be intensified by repeating steps 2-7, but at lower temperature and shorter times. Toning and intensifying (steps 7-9) may also be repeated. These repetitions are often unsatisfactory.
  3. If not celloidinised the preparations may have a coarse precipitate of silver.
  4. Although originally designed for the peripheral nervous system, Palmgrens silver impregnation may also be found useful for the central nervous system.


Drury, R.A.B. and Wallington, E.A., (1980)
Carleton's histological technique Ed. 5
Oxford University Press, Oxford, UK.




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