<Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2016) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2016) (Learn how and when to remove this template message) </Td> </Tr> <P> By the mid-1960s, the youth countercultures in California, particularly in San Francisco, had adopted the use of hallucinogenic drugs, with the first major underground LSD factory established by Owsley Stanley . From 1964, the Merry Pranksters, a loose group that developed around novelist Ken Kesey, sponsored the Acid Tests, a series of events primarily staged in or near San Francisco, involving the taking of LSD (supplied by Stanley), accompanied by light shows, film projection and discordant, improvised music known as the psychedelic symphony . The Pranksters helped popularize LSD use, through their road trips across America in a psychedelically - decorated converted school bus, which involved distributing the drug and meeting with major figures of the beat movement, and through publications about their activities such as Tom Wolfe's The Electric Kool - Aid Acid Test (1968). In both music and art, the influence of LSD was soon being more widely seen and heard thanks to the bands that participated in the Acid Tests and related events, including the Grateful Dead, Jefferson Airplane and Big Brother and the Holding Company, and through the inventive poster and album art of San Francisco - based artists like Rick Griffin, Victor Moscoso, Bonnie MacLean, Stanley Mouse & Alton Kelley, and Wes Wilson, meant to evoke the visual experience of an LSD trip . </P> <P> In San Francisco's Haight - Ashbury neighborhood, brothers Ron and Jay Thelin opened the Psychedelic Shop in January 1966 . The Thelins' store is regarded as the first ever head shop . The Thelins opened the store to promote safe use of LSD, which was then still legal in California . The Psychedelic Shop helped to further popularize LSD in the Haight and to make the neighborhood the unofficial capital of the hippie counterculture in the United States . Ron Thelin was also involved in organizing the Love Pageant rally, a protest held in Golden Gate park to protest California's newly adopted ban on LSD in October 1966 . At the rally, hundreds of attendees took acid in unison . Although the Psychedelic Shop closed after barely a year - and - a-half in business, its role in popularizing LSD was considerable . </P>

What is the origin of the term acid test
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