Summary and ConclusionsFrom the results of the peripheral circulatory measurements with iodinated (I131) human serumalbumin, we may conclude :1.At rest, the relative blood flow is of the same importance in the calf as in the foot, as well in normal individuals as in patients with obliterative arterial disease. In the latter, however, the speed of the circulation averages lower values in the distal part of the lower extremities.2.Reactive hyperemia increases the relative blood flow in normal subjects, in both calf and foot. In patients with obliterative arterial disease, the blood flow is generally increased in the calf but often decreased in the foot. While this reactive hyperemia increases the speed of the circulation in the distal part of the leg in normal subjects, this speed of the circulation is on an average decreased in patients with obliterative arterial disease.3. Circulatory measurements made on the foot during a reactive hyperemia test is an excellent method to evaluate qualitatively as well as quantitatively the degree of ischemia in patients with obliterative arterial disease. It is also an objective test for evaluating therapeutic results.