In an attempt to identify polysaccharide components in thin sections of D. maydis, procedures were employed such that a PAS localization could be carried out. Three different fixatives were evaluated ie. glutaraldehyde, formaldehyde and paraformaldehyde. These were used in conjunction with periodic acid (PA), thiosemicarbazide(TSC), and osmium tetroxide(Os) to localize polysaccharides in V. maydis using a pre-embedded reaction procedure. Polysaccharide localization is based on the oxidation of vic-glycol groups by PA, and the binding of TSC as a selective reaction center for the formation of osmium black. The reaction product is sufficiently electron opaque, insoluble in lipids, not altered when tissue is embedded, and has a fine amorphous character.