A conservative revolution: Julius Bernstein and his trip toward a membrane theory. A focus on bioelectrical processes in Mid-Nineteenth Century Germany

This paper aims at illustrating the historical circumstances which led Julius Bernstein in 1902 to formulate a membrane theory on the resting current in muscle and nerve fibres. 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 the Bernstein's subjective perception of that paradigm shift was that it represented a mere re-interpretation of the so-called "pre-existence theory" advanced by his teacher Emil du Bois-Reymond in the first half of the 19th century