Observation and Experiment

TWO years ago, in his Cutter Lecture, one of my predecessors pointed out that the object of any science is "the accumulation of systematized verifiable knowledge," and that this is to be achieved through "observation, experiment and thought" — the last including both criticism and imagination. He then added, "the use of the experimental method has brilliant discoveries to its credit, whereas the method of observation has achieved little."1 This dictum must surely prove, at least at first sight, more than a little disconcerting to the exponent of preventive medicine. In dealing with the characteristics of human populations, in sorting . . .