Julius Bernstein

He received his medical degree at Berlin in 1862, and two years later began work in the physiological institute at the University of Heidelberg as an assistant to Hermann von Helmholtz (1821–1894).

His "membrane hypothesis" explained the resting potential of nerve and muscle as a diffusion potential set up by the tendency of positively charged ions to diffuse from their high concentration in cytoplasm to their low concentration in the extracellular solution while other ions are held back.

In the English-language literature, the words "membrane breakdown" were used to describe Bernstein's view of excitation.

Bernstein's pioneering research laid the groundwork for experimentation on the conduction of the nerve impulse, and eventually the transmission of information in the nervous system.

He is credited with invention of a "differential rheotome", a device used to measure the velocity of bio-electric impulses.