Introduction

European explorers reported finding a long series of locally-used social and recreational drugs which were in this way added to what might be called the world-wide pharmacopoeia of pleasure. Most of the new drugs found during the period of exploration have remained in local use only and are inactive entries in world pharmacology. The older drugs were essential parts of the pharmacopoeia, and the modern ones were a small fraction of a new system of treatment that has, within the space of our own lifetime, revolutionized the practice of medicine, extended the useful lives of millions, and saved untold millions more. Human beings have long known that they can, in a sense, outwit this principle and produce the same or similar subjective effects with drugs.