Corrosive, colon, coagulation; diabetic, diuretic, dysentery; fatty, festered, fistula; replete, retentive, rigor. These words, which still belong to the modern medical lexicon, were written down for the first time in English in the late fourteenth century by Henry Daniel in the Liber Uricrisiarum. Daniel, with perceptive self-consciousness, announces his own novelty, proclaiming in his prologue that he has agreed to write his treatise in the vernacular because “I do not remember either reading or hearing about this science in English.”

As a medical pioneer, Daniel confronted the task not just of explaining authoritative knowledge in a new way, but also of developing many of the vernacular terms necessary to describe this material in the first place. The English names of diseases, bodily processes, and even body parts were still obscure, and Daniel aims to rectify this problem through a rich variety of creative methods. Sometimes anglicizing Latin words (cerebre, inflammacion, dissenterie), sometimes coining or reporting neologisms (ars bubbe, wunderlumpe), sometimes creatively translating entire phrases (“the branching vein” for vena ramosa and “head hair veins” for capillares), sometimes affixing characteristic suffixes (citrinish, warmish, newish), Daniel was always striving through his engaging vocabulary to make specialist knowledge “more openly taught,” using his linguistic innovations to make medicine available for a new, non-elite, non-Latinate audience.

At once idiosyncratic and accessible, charming and didactic, learned and popular, Daniel broke new ground in the history of the English language, and thereby provides a valuable perspective from which to historicize the vocabulary of his similarly innovative Ricardian contemporaries: Chaucer, Langland, Gower, and Trevisa.