Regius (Henri de Roy), a Dutch academic, was a major figure in disputes over Cartesianism in Utrecht, The Netherlands, during the seventeenth century. Regius received a medical degree from the University of Padua before returning in 1638 to his hometown of Utrecht to become a professor of medicine and botany at the university. Before his appointment there he gave private lectures based on the Dioptrics and Meteors, two of the essays published with René Descartes's Discourse on the Method (1637). What Regius found to be particularly congenial in these texts was the proposal there that observable phenomena be explained in terms of the mechanical properties of insensible material parts.

In 1641 Regius took advantage of his good relations with the new rector of the university, Gisbertius Voetius, to obtain permission to submit for discussion various "medical disputations." The first two disputations...