II. MODERN MEDICINE The Dawn of Modern Medicine.—The factors that produced the progressive medicine of the 16th century were excessively complex. Among them were certainly the invention of printing, the enlargement of the world by exploration, the revived knowl edge of Greek, the questioning that arose through religious differences. All affected medicine along with other studies of the day. There are, however, two factors which affected medicine in a manner different from all other subjects. One of these was the devastation caused by the epidemics of the time. The second was the advent of a school of art which studied the human body in detail and, therefore, demanded a knowledge of human anatomy. The main exponent of this method on the scientific as well as on the artistic side was Leonardo da Vinci (1452-1518) (q.v.). The modern father of anatomy, Andreas Vesalius was no unworthy successor of Leonardo.
The great anatomical work of Vesalius appeared in Vesalius initiated a period of exuberant scientific activity at Padua which long remained the centre of scientific medicine in Europe. From him descend a dynasty of important teachers who carried on the Vesalian tradition there. Even more important was the influence that he exerted through his great book. This imme diately transformed the practice of surgery. Of that art the leading exponent of the new school was the French surgeon, Am broise Pare (1517-9o).
Internal medicine lagged behind surgery. The anatomical reforms of Vesalius were unaccompanied by any commensurate advance in physiological knowledge, without which there can be no science of internal medicine. The practice of the physicians thus remained largely mediaeval, and the ruling idea was still the old humoral pathology.
(I) There was some improvement in the ancient medical texts. More reliable translations, notably of the Hippocratic works, be came available. These formed a substitute for the old translations
from the Arabic that had been the main source of the knowledge of Hippocrates and Galen in the middle ages.
(2) Exploration and the formation of settlements in new lands brought new drugs upon the market. These were often a mixed blessing, for some were useless, others dangerous. Nevertheless, several important drugs were introduced, especially from America. Among them were ipecacuanha, quinine and, by no means least, tobacco. The last was for long used as a narcotic. Moreover, there was a corresponding advance in botany. The beautiful herbals of the time exercised, by the accuracy of their execution, an exemplary influence on the development of medical science.
(3) There was advance in the knowledge of infectious disease. A rational theory of infection was set forth in 1546 by Girolamo Fracastoro (1483-1553) (q.v.) of Verona. He regarded infection as the passage from the infector to the infected of minute bodies, having the power of multiplication. The conception bears a super ficial resemblance to the modern germ theory of disease. An important contribution to the conception of epidemics was also made by the French physician, Guillaume de Baillou (1538-1616) who re-introduced the Hippocratic idea of "epidemic constitu tion," i.e., that particular seasons and particular years are of their nature subject to particular diseases. The idea was developed by the English physician, Thomas Sydenham (1624-89) (q.v.) and still has value.
(4) Fracastoro, de Baillou and Sydenham all made additions to the knowledge of particular infectious conditions; Fracastoro to syphilis and typhus ; de Baillou to whooping cough and rheuma tism; Sydenham to gout and to measles and many other diseases. Thus arose an exact body of teaching concerning these condi tions which was the necessary prelude to the introduction of effective preventive measures at a later date.