Convincing evidence is rapidly accumulating that most pulmonary emboli of extracardiac origin arise from thrombophlebitis in the deep veins of the lower extremities.1 The passage of an embolus from the leg to the lung can be prevented by division of the femoral vein. Indeed, Fine and Sears2 have recently urged this procedure in all cases of deep thrombophlebitis of the lower extremity as the most effective prophylaxis against embolism. The prevention of pulmonary embolus depends on the early recognition of the venous thrombosis, but the clinical evidence of phlebitis may be equivocal or entirely lacking until a pulmonary infarct indicates its presence. A method which can establish the diagnosis and locate the side on which the process lies has been provided by the venographic technic recently described by Bauer.3 The benefits of this diagnostic procedure are the subject of this communication.
The patient lies on his