The Speaker started by paying tribute to Walter Ernest Dixon, in whose honour these lectures are given at intervals of three years (Gunn, 1932; Dale, 1935).Pharmacological experiments on human beings started when the first medical man treated his first patient, for all good doctors are really doing experiments all the time. No two patients are quite alike and it is often necessary to find out by experiment what treatment suits each individual patient. The results of such experiments are stored up in the memory of the wise physician, but they do not always form a convincing, or reliable, guide for the rest of the world. When new remedies appear it becomes important to obtain objective evidence of their value in a form which is suitable for publication in a scientific journal. Pharmacologists have always been interested in this problem; some of the methods which they have used have been only distantly related to the problems of practical medicine, but in recent years similar methods have been applied to patients and I propose to discuss some of these clinical applications of pharmacology. I had already decided that the title of my