Man also looked inside himself — and sought answers to the most important questions. At the beginning of the century, Sigmund Freud discovered the unconscious. In 1938, Swiss chemist and Sandoz employee Albert Hofmann synthesized the psychedelic LSD-25 from the ergot alkaloid. In 1953, British writer Aldous Huxley took four-tenths of a gram of the hallucinogen mescaline, derived from cactus, under the supervision of psychiatrist Humphry Osmond.