Modification of Gomori Method for Alkaline and Acid Phosphatase Avoiding Artefact Staining of Nucleus. ∗

Summary and Conclusion

1. Staining sections before removal of the paraffin gives perfectly satisfactory, if not superior, results. Water and water-soluble material (dyes, substrate components, enzymes, etc.) readily penetrate the tissue structures exposed on the surface of the thin paraffin ribbon. The paraffin appears to act only as a filler which preserves the spatial relations of the various cytological elements during all staining and dehydration procedures. 2. Incubation of nondeparaffinized tissue sections in substrate gives a more accurate localization of phosphatase enzyme activity than the conventional method, and shows almost no activity demonstrable in the nuclei. It seems likely that the paraffin in the section prevents the lateral diffusion of the reaction products with their subsequent adsorption upon the nuclei. It is suggested this method be tried in other enzyme technics.