Peterfyi’s Double Embedding Method
In Peterfyi’s technique, the celloidin is more than just a glue to stick the tissue pieces together. It also supports it in the sense of protecting it from the harsh effects of hot paraffin. The double embedding sequence results in less shrinkage than paraffin alone, but not as little as celloidin alone. It is, however, considerably faster.
Procedure
- Prepare a 1% solution of celloidin in methyl benzoate. This should have the consistency of honey.
- Thoroughly fix the tissue and trim to an appropriate size no more than 3 mm thick.
- Thoroughly dehydrate the tissue to the absolute ethanol stage.
- Place in an equal parts methyl benzoate-ethanol mixture for a few hours.
- Infiltrate with celloidin in methyl benzoate overnight.
- Drain excess celloidin from the tissue and place tissue into xylene, 3 changes, an hour in each.
- Infiltrate with paraffin wax at 60°C for 3 changes of 2 hours each with intermittent agitation.
- Cast the block as for the paraffin infiltration technique.
- Section, float out, stain and coverslip as for a paraffin block.
Safety Note
Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.
References
- Gatenby, J. B. and Beams, H. W.,(1950)
The Microtomist’s Vade-Mecum Ed. 11, pp. 100-108, (para. 187-203).
J. & A Churchill Ltd., London, UK.
