Methenamine Silver
for Reducing Substances


Yellow gold chloride, 0.2% aqu.
Sodium thiosulphate, 3% aqu.
Stock Methenamine silver
Methenamine, 3% aqueous 100 mL Shake until the precipitate redissolves.
Silvering of the container indicates deterioration.
Silver nitrate, 5% aqu. 5 mL
Working Methenamine silver
Stock Methenamine silver 50 mL Make just before use and preheat to 56°C.
Borax, 5% aqu. 5 mL
Mallory bleach
Potassium permanganate, 1% aqu. 47.5 mL
Sulphuric acid, 3% aqueous 2.5 mL

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are likely to be satisfactory. A section adhesive is recommended.


  1. Bring sections to water via xylene and ethanol.
  2. Optionally, remove melanin with the Mallory bleach.
  3. Bleach in Oxalic acid for a few minutes.
  4. Rinse with distilled water.
  5. Treat with methenamine silver solution at 56°C. until impregnated
  6. Wash with distilled water.
  7. Tone in gold chloride solution for 1 minute.
  8. Rinse with distilled water.
  9. Fix in sodium thiosulphate for 5 minutes.
  10. Wash well with running tap water.
  11. Counterstain with neutral red for 1 minute
  12. Rinse with tap water.
  13. Dehydrate with ethanol, clear with xylene and mount with a resinous medium.

Expected results


  1. Methenamine is also known as hexamethylenetetramine and hexamine.
  2. Borax is sodium tetraborate.
  3. Impregnation is usually satisfactory when the sections develop a light brown colour.
  4. Toning is optional, but some microscopists prefer the colours that short toning gives.


Histology Bench Manual.
Prince George Regional Hospital




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