Chymistry and taste in the seventeenth century: Franciscus dele Boë Sylvius as a chymical physician between Galenism and Cartesianism.

Franciscus dele Boë (1614-1672), known as Sylvius, was one of the foremost chymical physicians of the mid-seventeenth century. He developed a highly influential and equally controversial theory of chymistry and physiology based on the interaction of acids and alkalis, taught students from across Europe, and performed and guided experimental research on digestion, glands, respiration, and the motion of the heart. Throughout his work, Sylvius grounded his knowledge of the acid and alkali chymical principles in the practice of tasting. In this paper, I expand our knowledge of Sylvius's chymistry and recover the surprising extent and significance of his use of his senses to assay chymical substances. I compare the uses of taste in more traditional Galenic medicine and the emerging chymistry in order to argue that Sylvius's reliance on taste grew directly out of his favoured chymical traditions. Looking to the broader context of philosophical medicine also allows us to see Sylvius's explicit commitment to Cartesian matter theory as an ideal: a metaphysical dream that he accepted yet criticised for its poor fit with the hard work and bodily experience central to proper chymistry and medicine.