Drawing of the brain and pineal gland from a physiology textbook by Rene Descartes (French, 31 March 1596 - 11 February 1650). Descartes believed that the pineal gland is where the human soul resides. Aside from his influential thinking in philosophy, Descartes made important contributions to mathematics, physiology, and optics. He also wrote a compendium of music. Color enhancement of BD8012.