Schiff's Original Reagent


Ingredient Amount
Pararosanilin 0.025 g
Distilled water 100 mL
Sulphur dioxide gas cylinder

Dissolve the pararosanilin into the distilled water. Under a fume hood, slowly bubble sulphur dioxide gas through the solution. Stopper well and store in the dark for one to two days. If not water clear, add activated charcoal and shake for about a minute. Filter the solution. Store at 0-5°C in a tightly stoppered bottle.


  1. Make sure that when you bubble the sulphur dioxide through the pararosanin solution you are doing so either under a fume hood, or outside at an elevation that stops anyone else from smelling it. Sulphur dioxide not only stinks, it can be dangerous in heavy doses. Bubble the gas slowly through the solution until it begins to change colour, then stopper and place in the dark.
  2. The solution should be colourless or very pale amber. Brown solutions will often stain poorly. Usually these have been made from a batch of basic fuchsin containing too little pararosanilin.


Gray, Peter. (1954)
The Microtomist's Formulary and Guide.
Originally published by:– The Blakiston Co.
Republished by:– Robert E. Krieger Publishing Co.
    Schiff, (1886). Annals de chimie (et de physique), v. 140, p. 93




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