Quarterly Journal of Microscopical Science, Vol s3-104, 155-167, Copyright © 1963 by Company of Biologists

Experiments on Fixation for Electron Microscopy

4. The Sodium Veronal Buffer

¹ Cytological Laboratory, Department of Zoology, University Museum, Oxford

Michaelis's sodium acetate / sodium veronal buffer is generally used for holding the pH of fixing solutions for electron microscopy at about pH 7.3 to 7.5. The acetate, however, has no buffering action on the alkaline side of neutrality. Experiments were therefore made to study the effect on preservation of cellular constituents when sodium acetate is omitted from Palade's (or its variants) and Luft's fluids. Exocrine cells of the pancreas, convoluted tubule cells of the kidney, and the testes of the mouse were used as test-objects, n-butyl methacrylate (generally partially prepolymerized) and epikote 812 were used for embedding. The preservation visualized in the micrographs did not seem to suggest any marked differences in the quality of fixation from that produced by fixation in Palade's and Luft's fluids. However, there is some evidence that comparable micrographs could be produced by fixation in simple solutions of OsO₄ in distilled water and subsequent embedding in suitable media.