Though he received his medical education in Edinburgh, William Withering was born and bred, and conducted his practice, in the Midlands of England, where he collaborated closely with medical and nonmedical colleagues who were pioneers of intellectual thought during the industrial revolution. Because of his profound botanical knowledge, he was able to identify Digitalis purpurea as the essential ingredient in a prescription dispensed by a herbalist, and systematically proceeded to show its value in patients with cardiac failure. He identified the cardinal symptoms of digitalis intoxication and worked out effective rules for the prescription of an infusion of digitalis. Withering's careful observations were also extended to botany and geology, and he was a key figure in the intellectual and scientific life of his area, a man whose legacy is not only the agent he identified but also the scrupulous way in which he evaluated it.