From the PREFACE. Man is an organism built around a food-tube. All man is, all he ever has been, has had its original motif in his need for food, and in the means he has evolved in order to secure it. History itself, in the main, is merely a series of accounts of how certain peoples pushed certain other peoples out of the way, in order to avail themselves of the others' food supply, or of their potential sources of food. Ethnologists and students of anthropology also tell us that by far the most important determining factor in racial development is the character of food upon which any people has lived. It has governed their stature, their intelligence, or lack of intelligence, their disposition. Upon whether a race is well or poorly nourished depends its status as conquerors, questing, energetic, civilization-making; or as docile serfs, blood-brothers to the cabbages, manioc, or rice they cultivate. Upon the difficulty of securing an adequate supply of balanced nutriment depends also their cultural development; for, if the aim and end of existence revolves around a grubbing of arid acres, it is obvious that not much energy can remain for speculative and creative endeavor. However, it is with the physiological aspects of food, as they concern the individual, that our attention is now engaged* In this connection, one might rather expect that in the half million or more years in which human beings have been inhabiting this planet, they would have developed an ample and adequate understanding of the uses of food, or an instinctive if not an acquired knowledge of proper food selection. Such is not the case. Even the greatest scholars have shown, and still show, a lamentable ignorance of food and its functions. The sour and crabbed Carlyle is a horrible example of this ignorance. Living for years, as he did, upon oatmeal — one of the poorest sources of nutriment a human could ever put into his stomach — Carlyle exhibited, all his life, the results of chronic intestinal auto-intoxication, plus a distressing unappreciation of food value; while Herbert Spencer, with all his vast wealth of information, did not know enough to select a regimen that would have lifted him out of the slough of chronic dyspepsia. The great Napoleon, for all his genius, proved himself the victim of his own gastronomic sins; for if he had taken time properly to masticate and insalivate his food, instead of making good his brag that he never spent more than ten minutes at a meal, he might have segregated England, instead of being segregated at St. Helena. What is even more surprising, however, is that many medical men, among them men who have won an enviable reputation as physiologists and clinicians, are almost equally at sea respecting the uses and the proper selection of food. So conflicting has been their experiences, so confusing their findings, that hardly any two modern authorities agree upon even the fundamentals of the science of nutrition....