Loewi found that electrically stimulating a heart causes it to release a chemical substance which changes the beating of a different heart when exposed to that chemical substance. Dale had already discovered neurotransmitters, one of which (acetylcholine) was the chemical responsible for the change in heart rate. This was eventually generalized to the rest of the nervous system.
Implication: The mind is implemented in an organ with distributed and modular function consisting of excitatory and inhibitory neurons communicating via electro-chemical synaptic connections.
[This post is part of a series chronicling history's top brain computation insights (see the first of the series for a detailed description)]