Humphry Osmond (1917-2004) was the British psychiatrist who coined the word "psychedelic" - "mind manifesting" - in a letter to Aldous Huxley. Osmond publicized the term at a meeting of the New York Academy of Sciences in 1957. "Psychedelic" is perhaps better term than "hallucinogen" since many classic psychedelic agents do not typically induce hallucinations.
Osmond introduced Aldous Huxley to mescaline in May 1953. Huxley sent Osmond a rhyme containing his own suggested coinage: "To make this trivial world sublime, take half a gram of phanerothyme." [Thymos (Gr): soul]. Osmond demurred: "To fathom Hell or soar angelic, just take a pinch of psychedelic."
San Pedro Cactus
Bernardino de Sahagun
The Doors Of Perception
Humphry Osmond (Wikipedia)
Mescal: A New Artificial Paradise