the various diseases much advance was made after the first quarter of the last century. The British physicians made especially valuable and numerous contributions in this field, displaying a practical and clinical bent contrasting with the dominant anatomical tone of the contemporary French school. In the last decade of the eighteenth century Edward Jenner (1749-1823) had introduced vaccination against smallpox. The second quarter of the nineteenth century was one of active development and many important contributions were made by the British clinicians, typically and brilliantly begun by Richard Bright (1789-1858), of London, who in 1827 elucidated the subject of renal diseases ("Bright's disease"). Among others eminent in this period were William Stokes (1804-1878) and Robert James Graves (1797-1853), of Dublin; and John Hughes Bennett (1812-1875), of Edinburgh, who was influential in bringing about the disuse of bleeding. The conceptions of continued fevers, which had previously always been vague and confused, were immensely clarified about this time by the differentiation of typhus and typhoid fevers as distinct diseases; this result was largely brought about by a contribution in 1837 by an American, W. W. Gerhard (1809-1872), of Philadelphia. Anesthesia with nitrous oxide was introduced in 1844 by Horace Wells, a dentist of Hartford, Conn.; with ether in 1846 by another dentist, W. T. G. Morton of Boston; and with chloroform in 1847 by Sir James Young Simpson, of Edinburgh.
About the middle of the last century the medical doctrines of the French school were introduced into Vienna by Rokitansky (18041878), who with Joseph Skoda (1805-1881) and others were pioneers in that development of scientific medicine in Austria and Germany which has attained such eminence. The identification of the cells of plants and animals by Schleiden and Schwann about 1838 opened the way to new conceptions of vital processes, and in 1858 Rudolph Virchow (1821-1902) presented his epochal doctrine of cellular pathology.
The discovery of the pathogenic role of bacteria and the development of bacteriologic science has been one of the most illuminating developments in the whole history of medicine, elucidating, as it has, the pathology of the large and important group of infectious diseases and vastly increasing the efficiency of medical and surgical treatment. Following earlier scattered discoveries, the great foundations of bacteriology were established by Louis Pasteur (1822-1895), of France, beginning during the fifties of the last century. The introduction of improved methods of research by Robert Koch (1843-1910), of Germany, about 1882, gave the science a vast impetus. The principal application of bacteriologic science has yielded incalculable benefits to humanity, as in the introduction of antisepsis by Sir Joseph Lister (1827-) during the sixties of the nineteenth century, of the spe-
