Polychrome Staining of Epoxy Semithin Sections Using Cacodylic Buffer as a Stain Solvent

Many polychromatic stains are in use for epoxy-embedded tissues (Horobin 1983). We should like to report a quick and easy polychromatic staining procedure that we find useful for routine use. Formerly the stain we used was prepared in 20 ml water and 5 ml 96% alcohol, and gave polychromatic staining only at pH 7.4 obtained by the addition of 1 N NaOH. However, the stain gave satisfactory results only for two or three days. We found that stabilization of the staining solution through the use of an ethyl alcohol-cacodylic buffer solvent increased the life of the staining solution. This was convenient because the cacodylic buffer is used in our laboratory as a component of fixatives, and is not prepared specially for the staining.