[The discovery of the nerve impulse. A chapter in the history of physiology].

Abstract

The subject of this essay is the discovery of the nerve impulse and its historical background. The main focus is on two important physician- scientists: Emil du Bois-Reymond (1818-1896) and Julius Bernstein (1838-1917). Du Bois-Reymond is considered the first scientist in his- tory who noticed what he called the "negative variation" during the stimulation of a nerve - the action potential in the language of today. Bernstein's main contribution was a theory called the membrane theory, which explains the activity in nerve cells as a phenomenon caused by differences in ion-concentrations in the interior versus the exterior of the cell. Bernstein's theory was based on the available knowledge from chemistry and cell biology in the late 19th century, in particular the Nernst equation. Bernstein's membrane theory paved the way for further investigations in the 20th century.