an aqueous solution of basic fuchsin or pararosaniline that is decolorized by sulfur dioxide; commonly prepared by addition of hydrochloric acid to a dye solution containing a metabisulfite or bisulfite salt; used for aldehydes and in histochemistry to detect polysaccharides, DNA, and proteins.Feulgen stain, periodic acid-Schiff stain, ninhydrin-Schiff stain for proteins