The 16th-century ethnographic study known as the Florentine Codex included a richly detailed account of natural history of the New World. In this lecture, Alain Touwaide—historian of medicine, botany, and medicinal plants—compares the Codex and contemporary European herbal traditions. He suggests that they represent the opposition between unknown and known—a dynamic force that led to many discoveries in medicine through the centuries. Recorded Dec. 5, 2017.