Representative images of time-dependent platelet adhesion and aggregate formation on collagen type III. Single platelets and platelet aggregates adherent on the surface appear bright and were visualized using epi-fluorescence video microscopy. Platelets adhered abundantly on the collagen surface, particularly near the upstream interface between collagen and albumin. No adhesion was observed on the albumin-coated surface. Flow was from left to right and the shear rate was 1000 s-1. These results are typical of 5 separate experiments.