Plain water as a rinsing agent preferable to sulfurous acid after the feulgen nucleal reaction

After staining for the Feulgen nucleal reaction with Schiff's reagent, slides were immediately submerged in running distilled or tap water and washed for 30 sec or longer. Rapid and complete removal of residual Schiff's reagent from the stained tissue will give preparations which show all details characterizing the nucleal reaction, and which are more durable in storage than those processed with the customary washing in a solution of SO₂. Care must be taken to insure that all parts of the slides are thoroughly washed and that, on the surface of the sections, no spilled adhesive or other interfering coating retards the washing. Standardization of the procedure for quantitative DNA determination may be facilitated by this modification.