THE place of anticoagulant therapy in the various types and phases of occlusive vascular disease, venous and arterial, has been debated ever since its introduction into clinical practice more than fifteen years ago. The widely divergent opinions and seemingly conflicting results of therapeutic trials that have appeared are unmistakable symptoms of defective knowledge, concerning not only the basic pathologic processes, which it is the aim of therapy to prevent, but also the management of therapy and the selection of the patients who are likely to benefit most. As a background for evaluating the various results in an attempt to establish . . .