# The New International Encyclopædia/Müller, Johannes

Edition of 1905. See also Johannes Peter Müller on Wikipedia; and the disclaimer.
MÜLLER, Johannes (1801-58). The most masterful, accurate, and influential physiologist and morphologist of his time. He was born at Coblenz, Rhenish Prussia, July 14, 1801; began to study theology, but abandoned it for medicine, beginning his medical studies at Bonn in the autumn of 1819. While there he prepared a prize essay, De Respiratione Fœtus (1821). He graduated in 1822. In the spring of 1823 he went to Berlin and studied with Rudolphi, then returned to Bonn as privat-docent, to teach physiology and comparative anatomy. In 1820 he was appointed professor extraordinarius in the University of Bonn, and he was made full professor in 1830. In 1833 he was called to the University of Berlin, where he succeeded Rudolphi as professor of anatomy and physiology, and after Meckel's death he edited the Archiv für Anatomie, Physiologie, und wissenschaftliche Medicin, and remained at Berlin until his death, which occurred April 28, 1858.
With his unusual powers of application, thoroughness, and breadth, his acuteness and penetration, young Müller opened up in different directions new fields of research. In 1826 he published an important work on the physiology of sight, and a treatise entitled Ueber die phantastischen Gesichtserscheinungen, and in 1827 a work based on his lectures on physiology; in 1829 his work on general pathology, and in 1833 the first part of his epoch-making Handbook of Human Physiology, which was completed in 1840. In 1834 he was elected a member of the Berlin Academy of Sciences. As a physiologist he was the founder of a new school, working by novel methods. To him physiology owes the foundation of Bell's law, the principle of reflex movements and other nervous activities; comprehensive and detailed views on vision and hearing; a thoroughly well-grounded knowledge of the nature of the blood, lymph, and chyle; the proof of the independence of the quality of glandular secretions from the grosser structure of the glands, and the knowledge of chondrin. Müller opposed the school of nature-philosophers and placed physiology on a sound basis. He was also a founder and leader in the new morphology. The science of comparative embryology was greatly enriched by his researches. He discovered the pronephric ducts which bear his name, and explained the nature of hermaphroditism; he made extended contributions to and laid the foundations of our knowledge of the embryology and metamorphoses of the echinoderms, and he examined into the mode of development of certain sharks, which led up to his subsequent studies on the ganoids and Amphioxus. The debt morphology owes him is shown in his discovery of the lymph-hearts of the Amphibia, the micropyle of the eggs of fishes, holothurians, and the like, the intimate structure of glands, of cartilaginous and bony tissue, of erectile tissue, of the musculature of the intestines, and the finer structure of the peritoneum.
His principal works in comparative anatomy and morphology were his Vergleichende
Anatomie der Myxinoiden (1834-43), which Carus has called ‘the codex of the morphology of vertebrates.’ In collaboration with Henle he published, in 1841, Systematische Beschreibung der Plagiostomen, and in systematic zoölogy his principal works were System der Asteriden (1842), with the collaboration of Troschel, and Horæ Ichthyologica. Besides these he published upward of two hundred articles, addresses, and reports, most of which appeared in the Transactions of the Berlin Academy of Sciences and in the Archiv für Anatomie, etc.
Consult the biographical notices by Du Bois-Reymond (Abhandlungen der Berliner Akademie, 1859), containing a list of his works; Virchow, Johannes Müller, Eine Gedächtnisrede (Berlin, 1858); Bischoff, Ueber Johannes Müller und sein Verhältnis zum jetztigen Standpunkt der Physiologie (Munich, 1858); Proceedings of the Royal Society of London, vol. ix., p. 556.