Abstract
Chromic acid, potassium permanganate and periodic acid apparently produce aldehyde from the same general group of substances. Chromic acid and potassium permanganate also destroy the aldehyde which they have produced, as well as that previously produced by periodic acid oxidation and by the Feulgen hydrochloric acid hydrolysis. Sulfite blockade, by occupying a considerable proportion of the aldehyde groups produced by periodic acid oxidation, creates a Schiff reaction similar to that produced by primary or secondary chromic acid or permanganate oxidation. It is suggested that the periodic acid Schiff positive substances which fail to give distinct Bauer and Casella reactions, are those with relatively few reactive 1,2 glycol, 1,2 OH,NH2, or 1,2 OH,NHR groupings per molecule.