The modernization of medicine was brought about to a large extent by the publication of the "Conservation of Energy" by Helmholtz, in 1847, and Darwin's "Origin of Species," in 1859. These books cleared away completely the myths and legends which had surrounded medicine at earlier periods, and taught medical students the strict need of proceeding entirely upon scientific grounds precisely as chemists, physicists, engineers, and others were already doing with wonderful success. Darwin's biological teachings appealed very strongly to medical men and influenced all their activities. Virchow's "Cellular Pathology," published in 1858, Huxley's textbooks on "Physiology" (1866) and on "Vertebrate and Invertebrate Anatomy" (1871-77) Haeckel's "General Morphology" (1866), and numerous medical encyclopedias and textbooks on practice and special diseases were the result of the new scientific spirit. New medical associations were formed and these promoted discussions, the reporting of observations, and the publication of innumerable monographs. Medical journals and magazines of a high character did fine educational work. The investigations on fermentation and putrefaction made in France by Pasteur caused Joseph Lister, professor of surgery at Glasgow University, to reflect upon the great mortality witnessed daily in the hospitals from pyæmia, erysipelas, tetanus, septicemia, gangrene, and other similar diseases. He observed that in spite of his great care to maintain scrupulous cleanliness in treating wounds, 45 per cent of his surgical cases were mortal. Pasteur's dictum that putrefaction is a micro-organic phenomenon, caused Lister to experiment with the view of preventing the development of microorganisms in wounds. Beginning with weak solutions of zinc chloride and zinc sulphite, he accidentally tried carbolic acid, securing surprising results, and two years later, in 1867, he published his monograph on antiseptic surgery which instantly became world-famous. Lister, instead of being carried away by the celebrity he attained, turned his attention to the scientific development of his important discovery. He investigated lactic-acid fermentation, the relation of bacteria to flesh inflammations and to the best methods of treating wounds antiseptically. Lister, however, was not the first to employ antiseptics in the treatment of wounds, and his great contribution to medical practice was due to the systematic manner in which he experimented. He was not a brilliant surgeon, but a deliberate and careful one whose chief desire was to have the patient recover. His whole surgical career was guided by this principle which proved so successful that before his death the whole medical profession saluted him as master, and when he died, rejoiced that his remains were entombed in Westminster Abbey.