THE manifold diversities in diet, the articles employed as food, the manner of preparing food, customs of eating, etc., among different peoples and at different times have been the outcome of fortuitous evolution, unguided and uninfluenced by definite physiologic principles. An account of the development of such dietary practises would present much of interest and would be included in a complete history of dietetics; but it is far too large a subject to be considered here, and the present paper will be limited to a brief presentation of the development of the various lines of knowledge constituting the scientific basis of dietetics, as it exists to-day.
Inquiring and speculative minds in all ages have endeavored to trace out the principles and laws governing diet. Prior to the modern scientific era, that is, during the entire ancient and middle ages, there was very little foundation of real knowledge on which a true science of dietetics could be based. Only the crudest objective characteristics of foodstuffs could be appreciated, such as the division of animal and vegetable, liquid and solid, etc. Notwithstanding the want of any adequate basis, from the time of Hippocrates a large proportion of medical literature was devoted to the subject of dietetics, and a multitude of treatises on food were presented characterized by chimerical speculation and fine-spun theorizing. Mythical properties and dangers were ascribed to different foodstuffs; rules were laid down in minute detail as to the use or prohibition of various foods in different morbid conditions which were without rational warrant; dietetic theories and systems were propounded which in the light of modern knowledge are seen to have been grotesque; and the authorities expounded their doctrines with an emphasis and dogmatism paralleled only by their real ignorance of the subject. Of all the mass of dietetic doctrine presented in the ancient