Carbohydrate histochemistry studied by acetylation techniques.

An acetic anhydride pyridine mixture acetylates hydroxyl groups in tissue sections. The acetyl groups can be removed from tissue sections by weak alkali. Sections acetylated by acetic anhydride pyridine no longer produce aldehydes after oxidation by periodic acid. Acetylated sections subjected to weak alkali regain the ability to produce aldehydes after oxidation by periodic acid. Acetylation of tissue sections and the removal of acetyl groups by weak alkali can be used as histochemical confirmation of the carbohydrate nature of materials coloring with Schiff's reagent after periodic acid.