“…The lesion is found in other naturally occurring (Farquhar, Vernier and Good, 19576;Trump and Benditt, 1962) and experimental (Feldman, 1958;Vernier, Papermaster and Good, 1959;Churg, Grishman and Mautner, 1960) glomerular lesions accompanied by proteinuria, and in some experiments seems to develop as a secondary consequence of glomerular proteinuria (Vernier et al, 1960;Anderson and Recant, 1962;Kurtz and Feldman, 1962). The glomerular epithelial cell is a n extremely complex structure, and this complexity, previously studied by thick sections and silver impregnation (von Mollendorff, 1927;Zimmermann, 1933 ;Willis, Tange and Gaew-im, 1964), has been fully appreciated only with the advent of scanning electronmicroscopy (Arakawa, 1970;Buss and Kronert, 1970).In this paper we are concerned with the sequence of changes in the scanning electron-microscope appearances of the glomerular epithelium of rats after administration of aminonucleoside and in the relation of these changes to the fusion of foot-processes described in transmission electron microscopy.…”