Hexamine silver stain is a classic method of showing basement membranes, modified by Grocott, the tissue is oxidized by chromic acid to expose the aldehyde groups of the mucopolysaccharides within the fungus, the aldehyde groups reduce the hexamine silver to black metallic silver, gold chloride converts the metallic silver to a more stable metallic gold, and at the same time makes the background clearer, and the seawave fixes and washes away the unreduced silver ions.