Osmond, a British psychiatrist born near London who had recently transplanted himself to Canada, was out of his mind on mescaline. The doctor had purposely dosed himself to observe the effects of the hallucinogenic drug, which he planned to administer to patients in area mental hospitals in the hopes of understanding schizophrenia. Before long, the cheaper, more readily available LSD would become his therapeutic chemical of choice, with hundreds of patients—as well as doctors and nurses—all tripping in the name of science.

D-lysergic acid diethylamide, better known as LSD, was first synthesized by biochemist Albert Hofmann in 1938. Hofmann was experimenting with different compounds in search of a cure for migraines. While LSD didn’t provide it, it did capture his attention when some spilled on his hand. Within the hour, he felt dreamy and dizzy. A deliberate experiment with the drug a few days later had him giggling uncontrollably. He needed an assistant to escort him home—a path, he later said, that made him feel as though he were inside a Salvador Dali painting.