Le Cat’s most important work. The Traité des sens was first published in Rouen in 1740 and again in 1742. It was the only part that was set in type of a greater work on physiology, which was never published. This is a new and updated edition. Le Cat, a friend of Voltaire´s, was a neo-Cartesian who believed in the union of the soul and the body and was one of the first adherents of a mechanistic approach to physiology. In his curious Traité des sens he opposes Haller’s doctrine of irratibility and sensibility of the nerves and considers the organism as a hydrualic machine. He postulates that the nerve force was a fluid which passes through the system of pipes and tubes. He also rejects Newton’s theory of colours and places Kepler’s second law of vision in doubt. Collation: Pp. (16), 328. With 16 engraved plates, some fold-outs with key plate in line drawing. Title leaf printed in red and black, and with an engraved printer's device. Binding: Contemporary marbled calf with five raised bands and richly gilt spine, red edges and marbled endpapers. Provenance: [Anders Johan] Hagström[er] (1753-1830). References: DSB, VIII, pp 114-16; Wangenstein, pp 75-76; Caillet 6342; Hirschberg/Blodi, III, pp 102, 289-94. Elgen Books (June 2004).