ORGANIZED athletics are at least as old as Homer, but it is only recently that they have been seriously investigated from the scientific point of view. It is an absorbing study ; how much power is exerted by an athleto running the hundred' in even time, the ' economy curve ' of a runner, the absolute limit that Nature imposes on human exertion, and so on. Professor Hill is both a distinguished scientist, who won the Nobel Prize for Medicine in 1922, and himself an athlete, and in the series of talks of which this is the first he will explain the physiological conditions that determine athletic success.