Another popular error is, that a large amount of disease is due to overeating, and that abstemiousness in diet is either certain to secure health, or is, at all events, indispensable for this purpose. Upon this point the reader should consult a capital paper by Dr. Austin Flint on "Food in its relations to personal and public health," which will be found in vol. iii. _Reports American Public Health Association_, N.Y., 1877. After remarking that many of the popular errors about food and diet are relics of old and abandoned medical theories, one of which is embodied in the not uncommon advice that one should always stop eating before the appetite is fully satisfied, and that food should only be taken at regular fixed periods, no matter how hungry one may be, he says: "Physiology, experience, and common sense are alike opposed to these popular notions relating to food. Conditions for perfect health are, first, a sufficient appetite; second, the gratification of normal appetite before the want of food reaches the abnormal degree expressed by hunger; third, the satisfaction of appetite by an adequate quantity of food. These conditions of health are fulfilled by compliance with instructive provisions for {196} alimentation. But, it will be asked, is appetite infallible as a guide in dietetics? Following it as a guide, is food never taken beyond the requirements of health? I answer, It is a reliable guide under normal circumstances. The inevitable circumstances of life are often not altogether normal, although producing no distinct morbid affection. Experience teaches, for example, that in a state of fatigue or exhaustion (which is not a normal state) inconvenience may arise from the full gratification of appetite; that if unusual exertions, mental or physical, are to follow, a hearty meal may occasion disturbance; and other examples might be added. Irrespective of abnormal or disturbing influences, if appetite be not infallible, it is, at all events, more reliable than a rule based on theoretical ideas, popular notions, or on purely physiological data. Moreover, it was evidently not intended that the quantity of food should be accurately adjusted to the needs of the economy. To do this is impossible, and therefore it is necessary to elect between the risk of taking either more or less food than is actually required. Which is to be preferred? Undoubtedly, it is vastly better to incur the risk of taking too much than that of taking too little. Nature provides for a redundancy, but there is no provision against a persistent deficiency. Ex nihilo nihil fit. An ample supply of alimentary principles is indispensable to nutrition; and inasmuch as the supply cannot be made to contain precisely the needed amount of the different alimentary principles, we may say that a superabundance of food is a requirement for health.