About eighteen months ago, one of us was confronted with the problem of differentiating, in a patient with a chronic toe ulcer, a very early thrombo-angiitis obliterans from a trophic or other disturbance. In this connection, it was thought that if the vessels could be visualized by means of a proper opaque substance, their condition would enable one to make an early diagnosis with the ultimate view of treatment before severe vessel alteration precluded all hope of cure. Besides, such visualization ought to be helpful in various disturbances of the vessels such as embolism, aneurysm and gangrenes, to determine the extent of the obliterative process.
Accordingly, experimental work was undertaken to determine whether or not visualization of the vessels was possible in the living subject. Sodium iodide, potassium bismuth tartrate, and dominal x (a German compound), which was advised by Dr. Pfahler, gave unsatisfactory roentgenologic films in animals. Shortly after