(p. 243) Loewi had long been interested in the problem of neurotransmission and believed that the agent was likely a chemical substance and not an electrical impulse, as previously thought, but he was unable to find a way to test the idea. It lay dormant in his mind for seventeen years. In a dream in 1921, on the night before Easter Sunday, he envisioned an experiment to prove this. Loewi awoke from the dream and, by his own account, “jotted down a few notes on a tiny slip of thin paper.” Upon awakening in the morning, he was terribly distressed: “I was unable to decipher the scrawl.”
The next night, at three o’clock, the idea returned. This time he got up, dressed, and started a laboratory experiment.
Source:
Meyers, Morton A. Happy Accidents: Serendipity in Modern Medical Breakthroughs. New York: Arcade Publishing, 2007.