There can be no reasonable doubt that they are merely evidences of childish vanity and puerile mendacity, and are only referred to here for the reason that young persons, ignorant of the laws of health, might attempt to emulate them, with results that could be but disastrous. _Nothing so preserves youth, health, and good looks as a sufficient amount of sleep, and it is pre-eminently the secret of long life._ Reference will be made in the chapter on the Hygiene of Infancy to the necessity of children sleeping as much as is possible. It will do no harm to say again here that nothing is so essential for the proper development of the body as sleep, _and that it is absolutely a crime to awaken a child except under circumstances of absolute necessity._ _Precautions in Respect to Eating._--A sufficient amount of sleep, and a proper quantity of digestible and nutritious food, thoroughly cooked and carefully masticated, are the things which above all others are most important for the maintenance of health. In the chapter on Foods, the nutritive values and digestibility of the various articles eaten by man will be discussed with sufficient thoroughness to instruct the reader as to a wholesome dietary; it is, therefore, not necessary here to go into the matter fully, but the subject is so important that a few general remarks will not be out of place. Eating should never, so far as is possible, be hurried. Nothing is more important for the proper digestion of food than its thorough mastication, and this can only be accomplished when sufficient time is allowed for eating. It is not necessary that this be done to the extreme advocated by some, but it is certainly of the highest importance that the food be so thoroughly chewed that it is reduced to fine particles, and that it should be so soaked in saliva that it may be swallowed without the aid of liquids of any kind. It is also desirable that food should not be taken while the individual is tired, so that it is a good plan where this condition exists for one to lie down for a short time before eating. Regularity in eating is likewise of importance, it being best to take the meals at stated periods; the consumption of food at irregular hours often leads to indigestion and is a practice which should not be indulged in. It is highly desirable to have food served under agreeable circumstances, digestion being accomplished in a much more satisfactory manner if pleasant conversation be indulged in during the meal, and if the food be of an appetizing character. Nothing is of more importance in connection with this subject than to have the food properly prepared. Not only is thorough cooking important from the standpoint of making foods digestible, but as is shown in another part of this volume, grave and sometimes fatal diseases are contracted by a neglect of this important procedure.