To meet the needs associated with high-speed flying, aviation medicine has developed an inflatable suit to be used for the prevention of blackouts that afflict the flyer when he pulls his plane sharply out of a fast dive. Because these suits were designed to counteract the force of gravity, which is multiplied many times during such maneuvers, they became known as antigravity suits or, more simply, as g-suits. The standard aviation garment consists of inflatable leggings and an abdominal binder, which, by constricting the lower part of the body, prevent pooling of blood. Wood and his co-workers1demonstrated the effectiveness of the g-suit in observations in the human centrifuge. Restall and Smirk2applied the principle to the study of hypotension produced with hexamethonium, while Seiker and his associates3described its mode of action in cases of postural hypotension occurring after sympathectomy. For several years we employed an