[DIGBY, Sir KENELM]. Two Treatises. In the one of which the Nature of Bodies; in the other the Nature of Mans Soule; is looked into: in way of discovery, of the Immortality of Reasonable Soules. Paris: Gilles Blaizot, 1644. Woodcut title device. Folio, old calf, upper cover detached; title soiled with some marginal fraying, some pale even browning to text and occasional staining, internal tear on oiii (affecting a few letters slightly). FIRST EDITION of Digby's most important work, in which he gives a complete survey of the physical, biological and philosophical concepts of his day. He describes his experiments on the heart by which he destroyed Descarte's objections to Harvey's conclusions on the circulation of the blood. Wing D1448; Duveen, pp. 171-72.