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Stieve’s Fixative

Stieve’s Fixative

Formula

MaterialAmount
Formalin, concentrated200mL
Mercuric chloride, sat. aqueous760mL
Acetic acid, glacial40mL

Description

As with other formalin-mercuric chloride mixtures, this is a fairly tolerant fixative, taking about 24 hours for thorough fixation. The mercuric chloride helps to produce sections with improved staining by both acid and basic dyes, and the acetic acid should provide well-defined nuclear morphology. Due to the mercuric chloride content, sections must be treated with the iodine-thiosulphate sequence to remove mercury pigment.

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 removed by transferring the tissue to 70% ethanol.

Mercury fixatives are less popular than in the past due to the fact that 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.

Safety Note

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

References

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