The term gravitational ulcer, first used by Dickson Wright (1931), refers to those chronic ulcers which occur on the lower half of the leg associated with one or more of the following: oedema, cyanosis, induration, sclerosis, pigmentation, loss of hair, eczema, and varicose veins of the affected limb. These are signs of chronic impairment of the venous drainage of the leg. The importance of gravity in the cause of this condition was stressed by Brodie (1846)* and by Hilton (1863). Brodie called such ulcers varicose, and they have long been thought to be due to varicose veins. Gay (1868) was probably the first to show, by clinical observation and careful dissection, that many were due to obstruction of trunk veins, deep and superficial, and that varicose veins often play no part. Gay's work seems to have been forgotten or has been neglected, and the view that varicose veins are the main or only cause has persisted (McPheeters, 1928). Dickson Wright (1931) and Homans (1939) held this opinion, though both believed that some gravitational ulcers were due to thrombosis of deep veins. However, in a series of 432 patients with leg ulcers Birger (1941) found that throm bosis was the chief factor. Nilz?n (1945) thought that cer tainly 41% or possibly 56% of such ulcers were caused by previous thrombosis, Bauer (1946) that 80-90% and Birger (1947) that 40% were due to this cause. The belief that varicose veins play a major part in the aetiology of these ulcers has affected treatment, which until the last few years has concentrated attention on such superficial varicose veins as might be present. Allen, Barker, and Hines (1946) considered that chronic venous insufficiency or stasis of the venous blood flow was due to obstruction of one of the main veins of the limb, particularly the ilio-femoral, as the result of thrombo phlebitis, neoplastic invasion, or external pressure ; incom petency of valves of the ilio-femoral vein resulting from thrombophlebitis without permanent obstruction of the vein ; or varicose veins of primary type (i.e., developing spontaneously), particularly those of long standing or considerable extent.