PREFACE Looking upon the human body from the physical point of view as the mostperfect, most ingeniously economical, and most beautiful of livingmachines, the author has attempted to write a little handbook ofpractical instruction for the running of it. And seeing that, like other machines, it derives the whole of its energyfrom its fuel, the subject of foods--their properties, uses, and methodsof preparation--has been gone into with unusual care. An adequate supplyof clean-burning food-fuel for the human engine is so absolutelyfundamental both for health and for efficiency--we are so literally whatwe have eaten--that to be well fed is in very fact two-thirds of thebattle of life from a physiological point of view. The whole discussionis in accord with the aim, kept in view throughout the book, of makingits suggestion and advice positive instead of negative, pointing outthat, in the language of the old swordsman, "attack is the bestdefense." If we actively do those things that make for health andefficiency, and which, for the most part, are attractive and agreeableto our natural instincts and unspoiled tastes,--such as exercising inthe open air, eating three square meals a day of real food, getting nineor ten hours of undisturbed sleep, taking plenty of fresh air and coldwater both inside and out,--this will of itself carry us safely past allthe forbidden side paths without the need of so much as a glance at the"Don't" and "Must not" with which it has been the custom to border andfence in the path of right living. On the other hand, while fully alive to the undesirability, and indeedwickedness, of putting ideas of dread and suffering into children'sminds unnecessarily, yet so much of the misery in the world is due toignorance, and could have been avoided if knowledge of the simplestcharacter had been given at the proper time, that it has been thoughtbest to set forth the facts as to the causation and nature of thecommonest diseases, and the methods by which they may be avoided. Thisis peculiarly necessary from the fact that most of the gravest enemiesof mankind have come into existence within a comparatively recent periodof the history of life,--only since the beginning of civilization, infact,--so that we have as yet developed no natural instincts for theiravoidance. Nor do we admit that we are adding anything to the stock of fears in theminds of children--the nurse-maid and the bad boys in the next alley...