Use of formaldehyde with pH 8 0 as a fixative for electron and fluorescence microscopy]

For fixation of the material to be investigated at the light and ultrastuctural level the author suggests to use 4% formaldehyde obtained by depolymerization of paraform on 0.1 M phosphate buffer with end pH 8.0 of the solution. This fixative stabilizes well glycogen and tissue structure. The ultrastructural characteristics of cells following continuous (up to 130 days) fixation are comparable with those obtained after fixation with aldehydes by conventional techniques. Results of histological PAS test, Feulgen's reactions and those to acid polycaccharides were identical to the results obtained in fixation with neutralized formalin. The possibility of prolonged storage of tissues makes it possible to perform delayed and repeated ultrastructural investigations of clinical and experimental material.