Simplification of the Manufacture of Schiff Reagent for use in Histochemical Procedures

Schiff reagent may be made by simply adding 1 g. fuchsin, 1.9 g. sodium metabisulfite to 100 ml. 0.15 N hydrochloric acid, shaking at intervals or mechanically for 2 hours, decolorizing with charcoal and filtering.To obtain perfectly colorless Schiff reagent, it is necessary that fresh activated charcoal be used. If the final product is not water white, a fresh sample of activated charcoal should be obtained, and the product retreated and refiltered.Schiff reagent precipitates a white crystalline substance after varying periods of cold storage, apparently a polymer which can be partly depolymerized by boiling and reconstituted into a Schiff reagent. The reconstituted reagent rather promptly precipitates again. Hence reconstitution is impractical and preparation of fresh batches at intervals of 2-3 weeks is recommended.