Henry Hallett Dale (1875-1968) was an English pharmacologist and physiologist. For his study of acetylcholine as agent in the chemical transmission of nerve impulses (neurotransmission) he shared the 1936 Nobel Prize in Physiology or Medicine with Otto Loewi. Dale and his colleagues first identified acetylcholine in 1914 as a possible neurotransmitter, Loewi showed its importance in the nervous system. During the 1940s Dale was embroiled in the scientific debate over the nature of signaling at the synapse. Dale and others believed that signaling at the synapse was chemical, while others believed that the synapse was electrical. It was later found that most synaptic signaling is chemical, but there are some synapses that are electrical. He lived to be 93 and died of natural causes.