IN a recent study it was found that the incidence of pulmonary embolism was reduced in hospital patients who wore elastic stockings as compared with those who wore nonelastic stockinette throughout their hospital stay.§ The explanation offered was that there was an increase in linear velocity (not in volume) of blood flow in the leg veins of those who wore elastic stockings. The acceleration of flow was assumed to result from a reduction in the caliber of the veins when they were compressed by the elastic stockings. This acceleration of venous flow supposedly lessened the tendency to phlebothrombosis in the . . .