BUCHNER, LUDWIG (1824-1899), German philosopher and physician, was born at Darmstadt. He studied at Giessen, Strasbourg, Wurzburg and Vienna. In 1852 he became lecturer in medicine at the University of Tubingen, where he published his great work Kraft and Stoff (1855). The extreme materialism of this work excited so much opposition that he was compelled to give up his post at Tubingen. He retired to Darmstadt, where he practised as a physician and contributed regularly to patho logical and physiological magazines. He continued his philosophi cal work in defence of materialism, and published Natur and Geist (1857), Aus Natur and Wissenschaft (vol. i., 1862 ; vol. ii., 1884), Fremdes and Eigenes aus dem geistigen Leben der Gegenwart (1890), Darwinismus and Socialismus (1894). He died at Darmstadt on May 1, 1899. Im Dienste der Walirheit (1899), a collection of selected essays from his works, contains a notice of him by his brother, Alexander Buchner.