Paul Flechsig

FLECHSIG, Paul (1847-1929), the famous German neuropathologist and psychiatrist, received his medical education in Leipzig. Starting from 1872, Flechsig was an assistant at the pathological institute of Professor E. Wagner in Leipzig, where he first began studying the central nervous system; to this period belongs the introduction into practice of Flechsig's horizontal method of sectioning the brain, the so-called "Flechsig method" (1877). In Leipzig, Flechsig received a professorship at the newly opened psychiatric clinic, which he rebuilt in 1882 and headed until 1920. Flechsig's main activity is associated with that direction in the study of the central nervous system which bears the name myelogenetic and is based on the non-simultaneous coating of nerve fibers with myelin during various periods of embryonic and postembryonic brain development. Based on this method, Flechsig for the first time identified new conduction tracts in the central nervous system that bear his name: the direct spinocerebellar tract, the primary optic and auditory tracts, and the temporal tract connecting the cerebral cortex with the pons. In addition, Flechsig described in detail the course of the pyramidal tracts, the structure of the corpus callosum, the posterior longitudinal fasciculus, and certain systems of the olfactory apparatus. Furthermore, Flechsig provided a map of the division of the cerebral hemisphere into separate areas, of which, based on his myelogenetic study, he counted more than 50, distinguishing the so-called "primary (pre-natal), intermediate, and terminal regions." Guided by his embryological and anatomical studies, Flechsig also singled out, apart from the sensory-motor zones, special association centers (see) that do not contain projection fibers. Flechsig's doctrine of "association centers" in the cerebral cortex encountered no small number of opponents both from anatomists and physiologists (Zimmerling, Dejerine, O. Vogt, Monakow). In recent times, the fascination with the myelogenetic method has considerably waned, although isolated works produced using this method still appear from time to time. Flechsig had many students, especially among Russian neuropathologists and psychiatrists, among whom belong: Bekhterev, Darkshevich, Chizh, Yakovenko, Blumenau, Klimov, and others. Remaining an anatomist all his life, Flechsig did not shy away from questions of psychology, physiology, and psychiatry, as shown by his famous speech in Leipzig delivered by him in 1897, which provoked numerous attacks and accusations of "crude materialism." Among Flechsig's works, the following are the best known: Die Lokalisation d. geistigen Vorgänge (Leipzig, 1896), Gehirn u. Seele (Leipzig, 1896), Anatomie des menschlichen Gehirns und Rückenmarks auf myelogenetischer Grundlage (Leipzig, 1920).