The Aymara Indians, of the Lake Titicaca plateau in Bolivia, have perhaps the largest materia medica ever reported from any native tribe. Their doctors or «Collawayus» from Charazani (Muñecas Province) are famous all over South America, even as far as Ecuador and Argentina; and even middleclass townspeople commonly consult them for cures. The botanical specimens here reported were collected by the ethnologist Professor Dr. Weston LA BARRE (now of Duke University) as Sterling Fellow of Yale University, and identified by the botanist Dr. Richard E. SCIIULTES, Curator of the Botanical Museum of Harvard University. Admittedly, empirical medicines are probably not all effective scientifically; and yet this list of plants must be expected to yield a higher percentage of valid drugs than a random sample of the flora of the country. For these people discovered and used quinine for malaria in pre-Colombian times; seaweed, for the cure of goitre; a mercury-pomade in llama-fat, for syphilis; ipecacuana as an emetic and purgative; Cactaeeae alkaloids for heart diseases; and many other plants of genuine medical value. The great usefulness in psychiatry of the Rauwolfia drugs as tranquilizers and Lophophora derivatives (e.g. mescaline) as psychotomimetic drugs—both of native tribal origins in their first uses—has alerted scholars once again to the untested possibilities contained in native pharmacopoeias.