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Watson’s Alum Hematoxylin

Watson's Alum Hematoxylin



Hematoxylin6 gDye
Ammonium alum6 gMordant
Distilled water300 mLSolvent
100% ethanol300 mLSolvent
Glycerol300 mLStabiliser
Glacial acetic acid30 mLAcidifier
Potassium permanganate or

Chloramine T or

Barium hydroxide

0.3 g

3.9 g

6 g


Compounding Procedure

  1. Dissolve the Alum in the water.
  2. If using potassium permanganate, add to the Alum solution.
  3. Dissolve the hematoxylin in ethanol.
  4. Combine the two solutions.
  5. Add the glycerol.
  6. Add the acetic acid (30 mL, unless using barium hydroxide, then add 120 mL)
  7. If using chloramine T or barium hydroxide, add to the solution.


  1. Bring sections to water with xylene and ethanol.
  2. Place into the staining solution for an appropriate time.
  3. Rinse well with water.
  4. Differentiate with acid ethanol if necessary.
  5. Rinse with water and blue.
  6. Rinse well with water.
  7. Counterstain if desired.
  8. Dehydrate with ethanol, clear with xylene and mount with a resinous medium.

Expected Results

  • Nuclei  –  blue
  • Background  –  as counterstain or unstained


  • Use only one of the oxidants named.
  • This is a modification of Ehrlich’s hematoxylin, and is said to be as effective. It was designed to be used immediately after preparation, eliminating the months required for atmospheric oxidation.
  • Gray gives a similar formula for Watson’s hemalum with potassium permanganate, but specifies only 0.6 grams alum. This may be an error.
  • The staining time should be determined by trial.
  • Acid ethanol is 0.5% – 1% hydrochloric acid in 70% ethanol.
  • Blueing is done with alkaline solutions such as hard tap water, Scott’s tap water substitute, 0.1% ammonia water, 1% aqueous sodium acetate, 0.5% aqueous lithium carbonate etc.

Safety Note

Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.


  1. Bolles Lee, A.. Edited by Gatenby, J.B. and Beams, H.W., (1950)
    The Microtomist’s Vade-Mecum. 11 ed.,
    Churchill, London, UK.
    Watson, (1943)
    Journal of the Royal Microscopical Society, v. 63, p. 20
  2. Gray, Peter. (1954)
    The Microtomist’s Formulary and Guide.
    Originally published by: The Blakiston Co.
    Republished by: Robert E. Krieger Publishing Co.