Wistar rat platelets allowed to adhere for 30 seconds (A) or 1 minute (B) onto Formvar-coated, carbon-stabilized grids, and subsequently fixed and stained with uranyl acetate. WF rat platelets allowed to adhere for 30 seconds (C) or 1 minute (D) onto Formvar-coated, carbon-stabilized grids. (A through D, original magnification ×3,700).