1869) founded at Breslau tlie first German physio- logical institute. His most important studies were concerned with the physiology of the organs of sense, especially of sight, the physiology of the muscles and nerves, the ciliary movement of the epithelium of the mucous membrane, the structure of the nerve-fibre (axis-cylinder) and of the ganglia, the glands secreting gastric juice, the sympathetic nervous system, and the
of the functions of the kidnej's, endosmosis, dis- covery of the nerves of secretion) and Ernst Wil- helm Hitter von Briicke (1819-92; studies of the ciliary muscle as a muscle of accommodation, theory of colours, physiology of the voice, structure of the muscle-fibres, biliary capillaries, digestion, absorp- tion). Karl von Vierordt (1S1S-S3) is associated with the chemistry of respiration and the counting of
history of development (discovery of the germinal the blood corpuscles; Adolf Fick (1829-1901) with
spot). Fundamental work in physiological physics was done by the brothers Weber, Erni'st lleinrich (1795-1878), and Eduard Friedrich Willielm (ls06- 71), both physicians, and the physicist Wilhelm Edu- ard (ISO 1-1)1); mechanism of the human organs of walking (Wilhelm and Eduard), experiments in irritability by means of induction currents, and the irritation of the pneumogastric and sympathetic nerves and its influence upon the heart (Ernst and Eduard). Physiological chemistry is representetl by Friedrich Tiedemann and Leopold Gemlin (1788- 1853; digestion, absorption and assimilation, the im- portance of the lymphatic system for absorption), Friedrich ^\ ohler (1800-82; artificial preparation of urea), and Karl Bogislav Reichert (1811-8.3; crystallization of blood pigment). We must also mention the nerve physiologist Rudolf Wag- ner (1805-64), discoverer of the tactile corpuscles. The greatest credit for developing modern physi- ology is due to the school of the ver- satile Johannes MuUer (1S01-5S). MuUer's importance, comparable to that of Albrecht von Haller, is due on the one hand to the results of liis own investigations (studies on the physiology of the organs of sense, the sympathetic nervous system, the theory of reflex action, the produc- tion of voice in the larynx, and the description of the cartilage-nucleus), and on the other hand to his activity in all branches of phj'siology and in his grasp of the entire field of physio- logical knowledge. The most important investigators of the century in the domain of histology, physiological chemistry, and physics, were pupils of Midler. Be- sides the above-mentioned investigators, Schwann, Kolliker, and Virchow, attention may be called to Robert Remak (1815-65; description of the marrow- less nerve fibres, of the course of the fibres in the brain and the sj^iual cord) and Heinrich Friedrich Bidder (1810-94; sympathetic nerve system, nerves of the heart, metabolism).
The doctrine of metabolism was advanced by the famous chemist, Justus Freiherr von Liebig (1803-73; excretion of nitrogen in the form of urea, importance of uric acid, albumen as a source of muscular strength), Theodor Ludwig Wilhelm Bischoff (1807-32; urea) and Karl von Voit (b. 1831; metabolism of nitrogen and organic albumen) . The latter, together with Max von Pettenkofer (1818-1901), made numerous experi- ments in the change of gases in man during rest and work. Georg Meissner (b. 1829; origin of the con- stituents of urine, muscle sugar), Schwann (discoverer of pepsin), Karl Gotthelf Lehmann (1812-05; pepton). The chemistry of the blood was investigated by Ernst Felix Josef Hoppe-Seyler (1825-95; blood pigment, blood gases, chemistry of cell and tissue), Julius Robert Meyer (1814-78; mechanism of heat), Her- mann Ludwig Ferdinand von Helmholtz (1821-94; physiological optics), and Emil du Bois-Reymond (1818-96; animal electrical phenomena, physics of the muscles and nerves). Just as versatile as Johannes Miiller were Karl Friedricli Wilhelm Ludwig (1816-95; physiology of the circulation and excretions, theory
physiology of the muscles and nerves; Moritz Schiff (1823-96) with the nervous system, discovery of the harmful results of the extirpation of the thyroid gland, function of the base of the brain and the cerebellum; Rudolf Heidenhain (1834-97) with the physiology of the glands; Alexander Rollett (b. 1834) with the glands of the stomach, blood; Eduard Friedrich Wilhelm Pfluger (b. 1829) with the gases of the blood, processes of oxidation in the body; Ewald Hering (b. 1834) with the theory of self-regulation of the act of breathing, sensitiveness of retina to colours, and Theodor Wilhehn Engelman (b. 1834), with electro- physiology, motion of the ciliary- epithelium, physiology of the heart and of the organs of sense. The localization of the brain was investi- gated especially by Gustav Fritsch (b. 1838), Eduard Hitzig (b. 1838), Leopold Goltz (1835-1902), and Sigmund Exner (b. 1846). Of emi- nent physiologists outside of Ger- many we may mention the Dutch- men Franz Cornells Donders (1818-89; physiological optics, de- termination of refraction) and Jakob Moleschott (1822-93; metabolism antl doctrine of foods).
Owing to the progress of the theoretical auxiliary sciences, prac- tical medicine reached a high state of development, especially in diagnosis, but also to a certain extent in thera- peutics. A general revolution was ef- fected by the establishment of physi- cal diagnosis. Auenbrugger's epoch- makingdiscovery, percussion (1761), pas.sed over in silence by van Swieten and de Haen, the leading spirits of the Vienna school, and men- tioned only in timid fashion by Maximilian StoU, might have been altogether forgotten, if Jean Nicolas Corvisart de Marest (1755-1821), after an objective examination, had not translated Auenbrugger's "In- ventum novum" into French, and pubUshed it in 1808 with a commentary. Ren6 Theopliile Hyacinthe Laennec (1781-1826) enriched the physical method of examination by the invention of auscultation (noting the different tones and noises in the chest by placing the ear against it). His pupil Pierre Adolphe Piorry (1794-1879) perfected percussion (definition of the borders and outlines of the organs, invention of the plessimeter, improvement of the stethoscope). Lacn- nec's invention attracted attention but slowly. His chief opponent was Francois Joseph Victor Broussais (1772-1838), but in England Jolm Forbes (1787-1861) and William Stokes (1804-78), and in Germany, Christian Friedrich Nasse (1778-1851), Peter Kruken- berg (1787-1865), Johann Lukas Schbnlein (1793- 1864), and others assumed a friendly attitude. Auscul- tation and percussion came into general use in the Germanic countries much later than in England and France, but they were then Vjrought to great perfec- tion by the Vienna physician Joseph Skoda (1805-81), who in 1839 treated physical diagnosis scientifically and fundamentally (auscultation and percussion). The new methods made possible the exact clinical diagnosis of diseases of the heart and the lungs to a degree never previously imagined. Besides Laennec and Skoda must be mentioned among the great number of in-
■Martin Charcot (1S25-1S93)