ations of perception, including hallucinations. In 1956 the psychi-
atrist Humphry Osmond (1917-2004), in correspondence with the
author Aldous Huxley (1894-1963), proposed the word psychedelic
(Greek psyche = mind, delos = visible, manifest) to describe the unique
effects of these substances on consciousness. Osmond proposed the
name in the following ditty, written in a letter to Huxley: “To fathom
Hell or soar angelic, just take a pinch of psychedelic.” In their plant
and fungal forms, and under the guidance of shamans, psychedelics
have been used for thousands of years to facilitate states of conscious-
ness conducive to psychological health. This has led to the use of the
word entheogen (generating god within) to emphasize their ritual use
to facilitate mystical-type experiences.
oO NH»MescalineAmong the known psychedelically active chemicals are mescaline,
lysergic acid diethylamide (LSD), psilocybin, psilocin, and dimethyl-
tryptamine (DMT). Mescaline was identified in 1897 by Arthur Heffter
(1859-1925) from peyote (Lophophora williamsii), a small cactus
growing primarily in Mexico, with a range extending northward into
southern Texas.
Heffter, a German pharmacologist, studied the chemical con-
stituents of peyote after it had come to his attention that this cactus
was used for its potent psychoactive properties by native peoples
of the Americas, consumed in ritual settings under the guidance of
shamans. Mescaline was the first psychedelic substance to be chemi-