Survival of the Luckiest

Abstract

In 1925,the Harvard physician Herman Blumgart injected a solution of a radioactive gas,radon,into the arm vein of a patient “to measure the velocity of the circulation”. He measured the time it took for the tracer to pass through the heart and lungs and reach the opposite arm.His experiment was little noted at the time but is of great historic interest.It was the first time a physiological process had been measured with a radio-active tracer,making the measurements with an externally-placed radiation detector directed at a part of the body of a living human being.