In 1775, the physician and botanist William Withering (1741-99) was informed of a folk cure for dropsy that had as its active ingredient the plant foxglove (Digitalis purpurea). Ten years later, after thorough trials on more than 150 patients, Withering published this monograph on the medicinal applications of the plant, not least to keep less experienced doctors from administering it to patients without the proper caution, given the plant's toxicity...