Albert Hofmann calculated that one teaspoon of LSD could affect 50,000 people. He arrived at that figure after accidentally absorbing a trace amount through his skin at the Sandoz laboratory in Basel on April 16, 1943 — 83 years ago today. He was 37, studying ergot (a grain fungus) for its potential to prevent post-childbirth hemorrhage. The accidental dose produced a dreamy, pleasant altered state. Three days later, he deliberately took 0.25mg. Soon, the streets of Basel warped around him on the bike ride home. Back at his apartment, the furniture seemed to breathe. When a neighbor showed up with milk to help, Hofmann saw a witch. He believed at one point he had died and arrived in Hell. Six hours after the dose, reality returned. April 19 is now commemorated as "Bicycle Day," a name coined by Illinois professor Thomas B. Roberts in 1985, according to the BBC . Hofmann spent decades arguing the drug belonged in doctors' offices. Sandoz began shipping it to psychiatric hospitals under the name Delysid.…