Throughout the sixteenth century, learned physicians across Europe performed a diverse array of “trials” of phenomena and published reports about them. This essay traces the phrase “periculum facere” (“to make a trial”) and related terms through natural history investigations, drug testing, chymical analysis, and anatomical discoveries. Physicians used ancient precedents, their learned expertise, and pedagogical authority to anchor the epistemic status of their trials and incorporated the historical narratives of their trial-making within arguments to factual and causal knowledge, even philosophical (...) scientia. Developed from engagement with things, ancient texts, other healers, and students, this lively tradition of contrived, first-person empirical trials flourished in some academic institutions, especially the University of Padua. The frequency and visibility of sixteenth-century medical trials, especially in the education of hundreds of students annually, is essential evidence for understanding how experimentation came to be widespread in early modern Europe. (shrink)