  While preparing Physiologia (Regius 1641a), Regius sent advance copies of draft disputations to Descartes. Since they were being presented in Utrecht as examples of Cartesian philosophy, Descartes recommended various changes, both to avoid needless controversy (for example, concerning blood circulation) and, more importantly, to avoid accusations of heresy against himself or Regius. Accordingly, he asked Regius to correct the thesis that the human soul is three-fold, and to argue instead that “in human beings the soul is one, namely a rational soul” (AT III, 369–74: Bos 2002, 63–69). During the year 1641, this pattern of prior consultation with Descartes continued; Regius accepted many of Descartes’ suggestions, and incorporated them into the final versions of the disputations.