A staining sequence for the differentiation of A-, B-, and D-cells of the islets of guinea-pig pancreas.

Four mu sections of guinea-pig pancreas that had been fixed in Bouin's fluid were deparaffinized, hydrated, oxidized in equal volumes of 0.3% KMnO4 and 0.3% H2SO4, decolorized in 2% oxalic acid and stained in 1% alcian blue in 70% alcohol for 10 min. Next they were stained for 5 min in chrome hematoxylin then into a dilute aqueous acid fuchsin solution followed by 2% phosphotungstic acid for 1 min. They were washed in running water until only the A-cells retained the red stain and were then counter stained with alcoholic aurantia for 5 min. Finally, the sections were cleared in xylene and mounted in D.P.X. Within the islets, B-cells stained blue green, A-cells bright red, D-cells pale yellow, while the acinar tissue stained blue grey. The wide separation between these colors represents a considerable advance on previous techniques for individual cell recognition within the islet.