The formula necessary for this study includes seven points of which the most important is the measurement of the reduction of the surface area of each ulcer. 100 leg ulcers, venous in origin, and representing a total surface area of 2.052 cm2, healed at varying speeds, directly proportionate to their initial surface area. To each surface area of ulcer there corresponds a length of time of half the cicatrization, equalling or less than thirty days which makes it possible to establish a point of reference in the development of cicatrization, and therefore a basic short-term prognosis. Once this time has passed, the diagnosis and the treatment are again the issue, with all that involves.