The concept of chemical neurotransmission is generally attributed to Thomas Renton Elliott (1877–1961). As early as 1904, Elliott had published a theory emphasizing the similarity between adrenaline and sympathetic nerve stimulation. It was not until 1921, however, that Otto Loewi (1873–1961) demonstrated experimentally that the transmitter substance at the parasympathetic nerve endings (Vagusstoff) is acetylcholine and that a substance closely related to adrenaline played a corresponding role at the sympathetic nerve endings. Loewi shared the Nobel Prize in Physiology or Medicine in 1936 with Sir Henry Hallett Dale (1875–1968) for their discoveries concerning the chemical transmission of nerve impulses.