Illustrations of the cerebrovascular system in Florentius Schuyl's Latin editions (1662, 1664) of René Descartes' Treatise on Man.

The Treatise on Man (1662, 1664) by French philosopher René Descartes (1596-1650) is the primary source for Cartesian physiology, but the accompanying illustrations were created after Descartes' death by a group of Descartes' disciples who were forced to create illustrations for Descartes' unfinished, and often vague and confusing, text. The iconographic tradition originating in the French edition (L'Homme, 1664) has predominated since the 17th century, whereas the Latin editions (De Homine, 1662, 1664) and their illustrations remain little known. Dutch physician and botanist Florentius Schuyl (1619-1669) both edited and illustrated the Latin editions with woodcuts and copperplate engravings. Although Schuyl faithfully illustrated Descartes' mistaken notions concerning the location and motility of the pineal gland, other mistakes and innovations were due to Schuyl rather than Descartes. These include (1) the mistake of illustrating the mythical human rete mirabile more than a century after Jacopo Berengario da Carpi (1460-1530) and Andreas Vesalius (1514-1564) had denied its existence in humans; (2) the mistake of illustrating an ungulate aortic arch as that of a human; and (3) the insight and courage to modify a Vesalian diagram to show a pre-Willisian circle of Willis, following Giulio Casseri (1552-1616) and Johann Vesling (1598-1649).