J Neurol (2006) 253 : 399–400 DOI 10.1007/s00415-006-0103-5 PIONEERS IN NEUROLOGY J. G. Barbara Louis Antoine Ranvier (1835–1922) JON 2103 Louis Antoine Ranvier was the most prominent French histologist of the late 19 th century.He held the chair of General Anatomy at the Collège de France (1875), thanks to his master Claude Bernard. Ranvier’s refined histological techniques and precise observations on normal and injured nerve fibres were soon recognised worldwide as classic work. Al- though Ranvier was not a clinician, nor primarily interested in pathol- ogy, his “Traité technique d’histolo- gie” (1875) [1] and observations on fibre nodes and the degeneration and regeneration of cut fibres had a great influence on Parisian neurol- ogy at the Salpêtrière. Ranvier was born in Lyon and obtained the ‘internat’ of Parisian hospitals with his friend Victor An- dré Cornil (1837–1908). They gave private histopathology lessons in the rue Christine in Paris, which were later published as a “Manuel d’histologie pathologique” (1869, 1873, 1876) [2]. Ranvier abandoned pathological studies, when in 1867 he became an assistant of Claude Bernard (1813–1878). The discovery of gaps in sheaths of nerve fibres (soon afterwards called nodes of Ranvier),in the context of Bernard’s physiology, led Ranvier to careful histological examination of myelin sheaths and Schwann cells [3].How- ever, besides his major research in- terests, Ranvier occasionally collab- orated with colleagues (such as L. T. J. Landouzy) on autopsies and histological observations of tu- mours and injured tissues. In 1872–1873, Ranvier combined both subjects, when he provided a precise description of the degeneration of cut fibres. Ramón y Cajal later thus commented on the scientific and technical contributions of Ranvier: “It is only the talent of such men as Waller and Ranvier that has been able to overcome the methodological deficiencies (to show the genesis, growth and evolution of the axons)” [4]. Ranvier confirmed the findings of Augustus Waller (1816–1870) on the degeneration of nerve fibres separated from the centre, but re- futed those of Vulpian on the au- togenous repair of cut peripheral fibre endings. Félix Alfred Vulpian (1826–1887), a former student of Jean-Pierre Marie Flourens (1794–1867), was an anatomo- pathologist, clinician and experi- menter at the Salpêtrière, with the clinician Jean-Martin Charcot (1825–1893). In his experiments Vulpian observed the development of frog embryo tails isolated from the body and he regarded nutrition, multiplication and differentiation of cellular elements as vital phe- nomena that were preserved in injured and isolated tissues. Ran- vier’s studies on the degeneration of nerve fibres (1872–1873) led Vulpian to change his views after Received: 22 September 2005 Accepted: 25 October 2005 J. G. Barbara, Ph. D. () Université Pierre et Marie Curie, Case 14 CNRS UMR 7102 and REHSEIS CNRS UMR 7596 7, quai Saint Bernard 75005, Paris, France E-Mail: jean-gael.barbara@snv.jussieu.fr Louis Antoine Ranvier (1835–1922)