Multispecies communities are flourishing in zones of abandon near the City of Knowledge, an abandoned U.S. military installation in Panama. Former bombing ranges have become habitat for a multitude of endangered animals: spider monkeys (Ateles geoffroyi), Baird’s tapirs (Tapirus bairdii), and cotton-top tamarins (Saguinus oedipus). Unexploded bombs and chemical weapons, rivets fastening an emergent ecosystem in place, have the indeterminate properties of the pharmakon. Classically, the pharmakon is a poisonous substance that can have a therapeutic effect depending on the dose, the circumstances, or the context. Isabelle Stengers understands the pharmakon as any obstacle...