Silver staining of collagen fibrils in cartilage

Direct visualization of individual collagen fibrils by light microscopy in human cartilage was achieved by applying a periodic acid-silver methenamine stain on plastic sections. Collagen fibrils, 100 nm in diameter or thicker, were delineated individually by light microscopy and were easily traced for a length beyond 100 microns. Thinner fibrils not readily visible optically were identified if arranged in compact bundles as occurring in the superficial zone of articular cartilage.