Bernstein's long path to membrane theory: radical change and conservation in nineteenth-century German electrophysiology

This article aims at illustrating the historical circumstances that led Julius Bernstein in 1902 to formulate a membrane theory on resting current in muscle and nerve fibers. It was a truly paradigm shift in research into bioelectrical phenomena, if qualified by the observation that, besides Bernstein, many other electrophysiologists between 1890 and 1902 borrowed ideas from the recent ionistic approach in the physical-chemistry domain. But Bernstein's subjective perception of that paradigm shift was that it constituted a mere reinterpretation of the so-called preexistence theory advanced by his teacher Emil du Bois-Reymond in the first half of the nineteenth century.