Atom-splitting appeared to most people, until 1945, an unrealistic activity to occupy the imagination of professors addicted to the use of quaternions, tensor calculus, and non-Euclidean geometry. However, its overwhelming possibilities were impressed on every literate person in that year by the losses of human life at Hiroshima and Nagasaki. Developments since then have made it clear to all that atomic energy could wipe out the human race unless ways were found to control it. Atomic scientists in particular expressed their consternation at the gruesome consequences of their wartime researches, and many resolved that every effort must be made thereafter to develop peacetime uses of atomic energy. A question that must have remained unuttered in some minds was whether applications of atomic energy to the problems of the physician and the engineer might eventually save enough lives to equal the 160,000 to 480,000 lost in 1945.
Since that time, an