Gomori's 1-2-3 Fixative

Formalin, concentrated 100 mL     1 volume
Mercuric chloride, sat. aqueous   200 mL 2 volumes
Water 300 mL 3 volumes

This formula has some similarity to formal sublimate, containing the same ingredients, albeit with a lower concentration of mercuric chloride and more formaldehyde. The mercuric chloride content means that sections must be treated with the iodine-thiosulphate sequence to remove mercury pigment.

Fixation should take a few hours to overnight, but tissues may be left in the fixative for a few weeks. Fixatives of this type produce sections with improved staining by both acid and basic dyes, and preserve nuclear morphology well. Note that mercuric chloride corrodes metals. For that reason all implements and containers coming in contact with the tissue during fixation must be made of plastic or glass until excess mercuric chloride has been washed out with water.

These fixatives are less popular than in the past due to their mercury content. Many jurisdictions forbid the disposal of mercury compounds through waste water systems, and special arrangements have to be made for safe disposal which do not contaminate the environment.

This may be a candidate for recycling. The simple formula contains a strong protein precipitant and that should facilitate removal of contaminating materials by simple filtration through a filter paper, after which it may be reused. This kind of recycling greatly reduces the volume of solution which needs special disposal.


Humason, G.L., (1967)
Animal Tissue Techniques
W.H. Freeman & Co., San Francisco, CA, USA




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