1906-2008 2002c-072 albert alteredstatesofconsciousness ayahuascaceremony collectionandpreservation colombia cross-culturalstudies dangerousplants ethnobotany ethnopharmacology folklore hallucinogenicdrugs hallucinogenicdrugsandreligiousexperience hallucinogens hofmann indiansofsouthamerica materiamedica medicinal medicine narcoticplants plants poisonousplants psychologicalaspects psychotropicdrugs psychotropicplants ritesandceremonies shamanism utilization vegetable vegetablemateriamedica