The study of the manifold problems presented by cancer has, in recent years, seemed to offer many more riddles than were previously thought to exist; but the history of medicine has never known a period in which problems could be attacked in so many different ways as those made accessible today by the working methods now at our command.
Nobel Lectures, Physiology or Medicine 1922-1941 - Nobel lecture for award received in 1926, Investigations on Spiroptera Carcinoma and the Experimental Induction - of Cancer (p. 148)