already tried to cstablisli a clinic after the Paduan model, but it was not till 10:57 that his son Otto was able to carry out his scheme. The immediate suc- cessors of the latter, Albert Kyper (d. IC.VS), and Ewald Schrevelius (1570-1616), continued this insti- tution in the Hippocratic spirit. Before Sylvius be- gan to teach there, the Leyden clinic had already gained world-wide fame. One of the first adherents of Harvey, .Sylvius, depeinling in part on Paracelsas and Ilelmonl, sought to explain physiological pro- cesses by suggesting fermentation (molecular motion of matter) and "vital spirits" as moving forces. Through "effervescence" acid and alkaline juices are formed, and through their abnormal mixture hyper- acidity and hyperalkalinity (i. e. sickness) originate. This simple doctrine, supported by the clinical activ- ity of Sylvius, fountl numerous adherents especially in Germany; but it made just as many opponents among the iatrophysicists, who were able to refute in part tliese untenable hypotheses. The two theories are, however, not absolutely opposed to each other, for both physics and chemLstry offer the means neces- sary for an explanation of physiological processes, and may form the basis for the construction of an exact medical science. At this time, however, physics and chemistry (especially the latter) were still too little developed for this purpose, and therefore the endeavour to create a system is much more appar- ent among the iatrochemists. Fortunately, the two parties found a common point of union in practical medicine, where the doctrines of the Hippocratic school were predominant.
Pioneers in Practical Medicine : Thomas Syd- enham AND Hermann Boerhave. — Both renounce all systems, and lay most stress upon the perfection of practical medicine. Thomas Sydenham (1024-89), physician at Westminster and known as the " Enghsh Hippocrates", laid down the principle that, just as in the natural sciences, so in medicine the inductive method should be authoritative. The main object of medicine, heahng, would be possible only when the changes lying at the root of disease and the laws governing its course had been investigated. Then also would the proper remedies be found. Following the idea of Hippocrates, he seeks the cause of disease in the change of the fundamental humours (humoral pathologj'). The activity of the physician was mainly to assi.st "nature". A man of the same intellectual build as Sydenham was Hermann Boerhave (1668- 1738), the most famous practitioner of his time, who in 1720 became clinical professor at Leyden. Being an iatrophysicist, he regards Hippocratism as able to hve only if the results of investigation in anatomy, physi- ology, physics, and chemistry are properly utilized. He tries to explain most physiological processes as purely mechanical. In contradistinction to the two professors of Kalle, Friedrich Hoffmann (1660-1742) and George Ernst Stahl (1660-1734), of whom the former supposed the ether (Leibniz's doctrine of monads) and the latter the " soul " to be the moving power, Boerhave did not care at all about any moving force that might possibly be present. With his death Leyden lost its importance as a nursery of medicine. His illustrious pupil and commentator, Gerhard van Swieten (1700-72), was called as teacher to Vienna in 1745, and there laid the foundation of the fame of the school whose most important representatives are An- ton de Haen (1704-76) and his successor as teacher, Maximilian Stoll (1742-8S). Under the eye of van Swieten and de Haen, but without recognition from them, a .simple hospital physician, Leopold Auenbrug- ger (1722-1809), published his epoch-making discovery that, by striking or rapping on the chest (percu.s.sionj, disease of the lungs and heart may be diagnosed from the various sounds elicited by such percussion. An important member of the Vienna school was Johann Peter Frank (1745-1821), director of the general hos-
pital, who was celebrated as a practitioner and as the author of a work, unequalled until then ("System einer vollstiindigen niedizinischen Polizey", 1779- 1819).
Among important practitioners outside of the school of Leyden were: the papal physician-in-ordi- nary, Giovanni Maria Lancisi (1654-1720), who estab- lislied a chnic in Rome after the model of Leyden; Giovanni Battista Borsieri (Burserius de Kanilfeld, 1725-85), professor at Pavia; James Keill (1673- 1718); Richard Mead (1673-1754); John Freind (1675-1728, smallpox); John Pringle (1707-82) and John Huxham (1694-1768), investigators in epidemi- ology; John Fothergill (1712-80; diphtheria and in- termittent fever). Albrecht von Haller developed an important school in Gottingen as van Swieten had done in Vienna. The first members of the Gottingen school were: Paul Gottlieb Werlhof (1699-1767; in- termittent fever) and Johann Georg Zimmermann (1728-95).
Anatomy in the Eighteenth Century. — During this period normal and pathological anatomy were more cultivated than microscopy. The greater num- ber of investigators that we have to consider won fame in the field of surgery. Starting from the school of Leyden the following anatomists deserve mention: Govert Bidloo (1649-1713) and Bernhard Sigmund Albinus (1697-1770; anatomical charts) ; in Amster- dam, Friedrich Ruysch (1638-1721), and Pieter Cam- per (1722-89), the inventor of craniometry and of the elastic truss for hernia; in Italy, Antonio Maria Val- salva (1666-1723; eye and ear) and Giovanni Do- menico Santorini (1081-1737); in Paris, the Dane Jakob Benignus Winslow (1669-1760; topographical anatomy); in England, James Douglas (1675-1742; peritoneum); Alexander Munroe (1732-1817; bursa mucosa), and William (1718-83) and John Hunter (1728-93) both known also as surgeons; finally in Germany, the anatomist, surgeon, and botanist, Lorenz Heister (1683-1758), Johann Friedrich Meckel (1724-74; nerves); Johann Gottfried Zinn (1727-59; eye); Johann Nathanael Lieberkiilm (1711-65; in- testine); Heinrich August Wrisbei-g (1739-1808; larynx), and Samuel Thomas Sommering (1755- 1830). Abnormal anatomical changes in organs had been recorded since the time of Vesalius, but these were for the most part merely incidental observations, and nobody had tried to trace sys- tematically the connexion between them and the symptoms occurring in the living body. The best survey of the achievements of the earlier centuries is offered in Theophil Bonet's " Sepulchretum anatomi- cum" (1709). As the scientific founder of pathologi- cal anatomy we must mention Ciiovanni Battista Mor- gagni (1682-1771), professor at Padua, whose famous work, "De sedibus et causis morborum" (1761), usually contains, besides the results of post-mortem examinations, a corresponding history of the diseases. This field was cultivated in France especially by Joseph Lieutaud (1703-80) and Vicq d'Azyr (1748- 94), and in Leyden by Eduard Sandifort (1742-1814). Germany had an important investigator in the days before itorgagni, viz., Johann Jakob Wepfer in Schaff- hau.sen (1620-95). In Vienna, autopsies on those who died in the clinic were first regularly made by Anton de Haen. For a strictly systematic treatment of the whole field we are indebteii to the London physician, Matthew Baillie (1761-1823), who published the first pictorial work on pathological anatomy.
Surgery in the Seventeenth and Eighteenth Centuries.— The eminent surgeons of the seven- teenth century are: Cesare Magati (1579-about 1048), professor in Ferrara and later a Capuchin monk, who simplified the treatment of wounds; Marc' Aurelio Severino (1580-1656; treatment of abscesses, resection of ribs); the already mentioned anatomist, Fabrizio ab Aquapendente (re-introduction of tracheotomy,