Albert Hofmann

An early fan and willing experimenter of Albert Hofmann's LSD-25, pictured in New York's Central Park in 1968.

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One of the most notorious self-experimenting scientists was Albert Hofmann, the Swiss chemist who synthesized LSD-25, the drug that eventually fueled the expanding minds of millions of people in the 1960s and beyond. But there was a time before Hofmann or anyone else knew what LSD was capable of doing to the human mind, and that's when the chemist used himself as a guinea pig for his new compound.

In 1943, Hofmann was a chemist at Sandoz Pharmaceuticals experimenting with synthesizing the active ingredient in ergot, a fungus that grows on grain and contains extremely hallucinogenic properties. He isolated the active ingredient, LSD-25, and while he was handling the preparation, he began to feel sick. He went home, but the effects of the compound were intriguing enough that he approached it once again three days later.

This time, Hofmann measured out 250 micrograms (millionths of a gram) and ingested it. In short order, he once again began to feel bizarre and he left the lab, riding his bicycle home. This bike ride, part of the world's first trip, has come to be commemorated each April 19 as Bicycle Day by LSD adherents [source: NNDB]. At home, Hofmann recorded the effects of the drug he self-experimented with that day. He wrote, "I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors," [source: Tweney].

While it was initially used for several years in psychotherapy and by the CIA as a brainwashing drug, LSD was outlawed in 1967. Hofmann later wrote an autobiography on his drug, called "LSD, My Problem Child."