Müller, Johannes Peter

Born July 15, 1801, in Koblenz; died Apr. 28, 1858, in Berlin. German naturalist, one of the founders of modern physiology, comparative anatomy, and embryology.

Müller graduated from the University of Bonn in 1822. He was a professor at the University of Bonn from 1830 and at the University of Berlin from 1833. His principal works were devoted to the study of the central nervous system (mainly the reflex activities of the spinal cord and medulla oblongata) and of the sense organs. Müller formulated the theory of specific irritability of the sense organs, according to which perceptions are the result of manifestations of an internal property (“specific irritability”) of each sense organ. In Materialism and Empirio-Criticism, V. I. Lenin, criticized Müller’s “physical idealism,” clearly separating Müller’s achievements in the investigation of neuro-psychic events from his idealistic treatment of the facts he obtained (see V. I. Lenin, Poln. sobr. soch., 5th ed., vol. 18, p. 322). The untenability of Müller’s physical idealism was demonstrated by I. M. Sechenov and especially by I. P. Pavlov—the creator of the concept of analyzers.

Müller also studied the structure of cyclostomes (Mixini), the lymphatic hearts of amphibians and reptiles, the sympathetic nervous system of invertebrates, and the embryonic and postembryonic development of echinoderms. He discovered and characterized the larval stage in Turbellaria (Müller’s larva). In Nemertea, he discovered and described the canal that in all vertebrate embryos joins the cavities of the tubules of the pronephros with the cloaca (Müller’s duct). He also described the early stages in the development of the human embryo and investigated the microscopic structures of many tissues, such as connective tissue, kidney, bone, and cartilage. In 1834, Müller founded the journal Archiv für Anatomie, Physiologie und wissenschaftliche Medizin.