Balsamo del Peru: an American remedy misnamed, and the Spanish route that carried it to China and Japan

The resin the world still calls balsam of Peru comes from Central America, not Peru. This object records what the tree is and where it grows, the Nahuatl name hoitziloxitl, the tapping technique and its yield, the gatherers who sold the sap on, the galleon cargoes that took it across the Pacific into Chinese and Japanese medical writing, the adulteration that followed it, and what became of it: a standard allergen in the European patch-test series.