Introduction

Abstract

The practice of deliberately inhaling various gases or vapors in order to induce an altered state of mood or sensibility is not new. As noted repeatedly in other reviews (eg, Cohen, 1973; Novak, 1980), it was recognized in early Greek civilization as an adjunct to divination; indeed, it has now become customary, if not obligatory, to refer to the Oracle at Delphi before considering the more recent history of the subject. According to legend, the priestess at the Temple at Delphi would achieve communion with the Gods by inhaling the naturally-occurring gas that emanated from a fissure in a rock. Inhalation would induce a trance-like state. Her mystical observations and utterances while in this state were interpreted by the Temple Prophet and issued as divine pronouncements to those seeking guidance.