Brain Waves and the Interferometer

　The present talk is a discussion of a piece of research　in which ideas from pure mathematics, physics, and phy—siology have converged into a single piece of research drawing from all three　fields．　Let me first say a word or two about the physiological phenomenon　which is the topic of this research．　For a long time it has been known that　the human animal body is the locus of many different sorts of repetitive pheno—menon．　Everyone knows that the heart beat is a repetitive phenomenon　spread out in time, and that the various characteristics of this phenomenon，　such as those concerning its rate, its strength, and its regularity, are potent　indices of the condition of the body and thus aids in diagnosis．　Moreover, it has　long been recognized that the movements of the digestive tube by which food　is pushed along through the stomach and intestine by which excreta are　rejected, have a definite, observable, and even measurable character．

　The heart and the digestive tube are systems of muscles．　The more or　less periodic contraction of these muscles is a part of the general property　of muscles which enables them to contract and to perform certain tasks of　contraction with a certain degree of regularity．　In walking, for example，　is a phenomenon in which the voluntary muscles, the muscles controlled by　the will show a repeated regularity of behaviour not unlike that shown by　the involuntary muscles of the digestive tube in peristalsis or by the veryspecial muscle of the heart in its beat．