# Catholic Encyclopedia (1913)/Johann Müller

From volume 10 of the work.
Physiologist and comparative anatomist, b. at Coblenz, 14 July, 1801; d. at Berlin, 28 April, 1858. He was the son of a shoemaker, but his mother succeeded in obtaining for him a good education. During his college course at Coblenz, he devoted himself to the classics and made his own translations of Aristotle. His first intention was to be a priest, but at eighteen his love for natural science turned him to medicine and he entered the University of Bonn in 1819. While a student he won a prize for original work on "Respiration of the Foetus," a thesis that has been declared the best scientific work ever presented by a student in a prize competition. He received his degree of doctor for a thesis on animal movement. In 1824 he became Privatdocent at Bonn, and in 1830 ordinary professor of medicine. Before teaching at Bonn, he had studied for two years with Rudolphi at Berlin, and in 1832 was appointed his successor in the professorship of anatomy there. In 1847 he was elected Rector of the University.
Müller is justly regarded as the founder of modern physiology. His claim to this title rests not only upon his personal contributions to the science, but also upon his power of co- ordinating the results obtained by his predecessors, and of directing into new fields of investigation the disciples who profited by his suggestive teaching. To accuracy of observation he added such a grasp of principles and so clear a comprehension of the bearing of other sciences upon physiology that his reasoning, based throughout upon facts, is philosophical in breadth and penetration.
His first monograph, an elaboration of his prize essay, "De respiratione foetus," was published in 1823, and was followed (1826) by two others on optical illusions and on the comparative physiology of vision. The last-named abounds in observation upon the structure and functions of the eye in lower animals, especially in insects. Among the other subjects to which Müller devoted careful and successful research may be mentioned: reflex action, the chemical composition of blood plasma, the presence of chondrin in cartilage, hermaphroditism in human beings, the minute structure and origin of glands in man and animals, the lymph hearts of amphibia, and those ducts of the preliminary kidney in the foetus which have since been called by his name. His study of the lower animals resulted in the discovery of alternate generations and in a satisfactory account of the metamorphoses of echinodermata.
From 1834 to 1840 he edited the "Archives of Anatomy and Physiology" (Müller's Archives) and contributed articles to various scientific reviews. His own contributions to medical literature number over two hundred, most of them of great significance. His principal work is the "Handbuch der Physiologie des Menschen," which was published in 1833 and has appeared in numerous editions and translations. But the benefit which he rendered to science as an original investigator and medical editor is surpassed by his work as a teacher. Among his pupils were most of the men who made Germany the Mecca for scientific students in the latter half of the nineteenth century. They included Virchow, Helmholtz, Schwann, Du Bois-Reymond, Lieberkühn, Max Schultze, Brücke, Claparéde, Haeckel, Henle, Guido Wagener, Reichert, Ludwig, Vierordt, and Kölliker. All of these men agree in proclaiming him the foremost physiologist of his time. Most of the important scientific societies of the world honoured him. Throughout his life he was loyal in his adherence to the Catholic Church, and his fellow-Catholics of the Rhine have erected a noble monument to his memory at Coblenz.
VIRCHOW, Johann Müller (Berlin, 1858); BRUECKE, Medical Times and Gazette (London, 17 July, 1858); DU BOIS-REYMOND, Gedaechtnissrede auf Johannes Müller (Berlin, 1860); WALSH, Makers of Modern Medicine (New York, 1910).
JAMES J. WALSH