Silver Impregnation for Electron Microscopy

Heavy metal impregnation of specimens for electron microscopy offers a means for differential "staining" of various tissue components and cellular constituents. Of many silver impregnation methods, one of the most useful is Gomori 's silver methenamine (1) after periodic acid oxidation (PA-SM) (2, 3). Several authors have applied silver impregnation to electron microscopy (4-7), mainly for the demonstration of connective tissue fibers. Det tmer and Schwarz (3) applied Gomori 's silver methenamine to the study of teased preparations. We have adapted this procedure to the impregnation of small blocks of tissue which are then embedded in plastic and sectioned in the usual manner.