Role of Blood Platelets in Thromboembolism

DEVELOPMENT OF MODERN CONCEPTS OF THROMBUS FORMATION IN THE first half of the nineteenth century, thrombosis of blood vessels was held to result either from excessive coagulability of the blood or from exudative inflammation of the vascular wall. Virchow's views¹influenced subsequent thought on the subject of intravascular clotting by their stress on the importance of slowing or stagnation of blood flow as well as on altered "molecular attraction" between the blood and the vascular wall. By means of experiments in living animals, Mantegazza²(1869, 1871) and Zahn³(1875) assembled proof that thrombosis is not equivalent to simple clot formation but consists primarily in a process of selective precipitation of protoplasmic elements from the flowing blood at sites of vascular injury to form a homogeneous, grayish white deposit (the "white thrombus"). With complete occlusion of the lumen by the white thrombus, the blood which is trapped in