Michael

“Intrigued, Hofmann decided a few days later to conduct an experiment on himself—not an uncommon practice at the time. Proceeding with what he thought was extreme caution, he ingested 0.25 milligrams—a milligram is one-thousandth of a gram—of LSD dissolved in a glass of water. This would represent a minuscule dose of any other drug, but LSD, it turns out, is one of the most potent psychoactive compounds ever discovered, active at doses measured in micrograms—that is, one thousandth of a milligram. This surprising fact would soon inspire scientists to look for, and eventually find, the brain receptors and the endogenous chemical—serotonin—that activates them like a key in a lock, as a way to explain how such a small number of molecules could have such a profound effect on the mind. In this and other ways, Hofmann’s discovery helped to launch modern brain science in the 1950s.”
― Michael Pollan, How to Change Your Mind: What the New Science of Psychedelics Teaches Us About Consciousness, Dying, Addiction, Depression, and Transcendence