Man's place in future history will depend in no small degree on the food he eats. The truth of this was foreshadowed about two decades ago when it was discovered that an animal's life processes may be profoundly disrupted by the omission from its food of any one of a number of substances, each of them ridiculously small in the amount required. Today there has been added the further, highly significant, observation that under certain circumstances an animal's life may be greatly improved by the addition of appropriate foods to a diet that previously had been regarded as entirely satisfactory. Through this knowledge, physiologists have been able to influence to a surprising degree the life history of their experimental animals and in some instances so to improve the stock as apparently to produce a new species.1Can this be applied to man? Can man, by giving thought to the