Although thromboangiitis obliterans is considered a local vascular disease, its progressive course and the occasional general distribution of its lesions suggest a systemic origin. Increasing numbers of autopsy and clinical reports1 indicate that almost any artery of the body may be the site of thrombosis. Bacteriologic studies2 have not established infection as the cause of thrombosis, and neither infection nor thrombosis adequately explains the clinical and pathologic peculiarities of the disease. Homans3 expressed the belief that the inflammatory characteristics4 of the peripheral lesions are secondary changes due to thrombosis and to complicating infection. The lack of knowledge concerning thromboangiitis obliterans has made early diagnosis difficult and evaluation of therapeutic measures uncertain. Changes in the circulating blood in thromboangiitis obliterans, as reported by Koga5 in 1913, led him to believe that the vascular disease is secondary to increased viscosity of the blood. Accordingly, the treatment he