First, regularity in the hours of rising and retiring, namely, regulating the minimum period to be devoted to sleep. There is much conflict of opinion as to the amount of sleep necessary for the average adult. We have in mind an old saying which runs as follows: "Six hours' sleep for a man, seven for a woman, and eight for a fool." This is somewhat arbitrary, and, moreover, is not in harmony with physiological law. In the first place, no hard and fast rule can be laid down that will cover all cases. Apart from the difference of sex, there are temperamental conditions which vary with every case. We are decidedly of the opinion that eight hours' sleep is necessary for the adult individual. It has been affirmed by some authorities that the more the individual sleeps the longer he will live, which is a perfectly rational claim, in view of the fact that night is Nature's repair time, when she is busy at work replacing the ravages committed by wear and tear during the day. It is a well known fact that nearly all growth takes place during sleep. Again, it is a fact not generally known that the heart receives no nourishment during the period of contraction, owing to the pressure upon the arteries which supply it with nutriment. It is only during the infinitesimal pause between the contractions that these arteries can carry blood to the heart tissue; hence during sleep the heart- beats differ from those of our waking hours, being fewer in number, and with a more decided pause between. Now, the heart being to the body what the mainspring is to a watch, the necessity of affording it ample time for recuperation becomes apparent. Having stated that eight hours' sleep is the minimum amount for the individual, the question of regularity presents itself, and this should be understood to refer especially to the time of rising, which, unless the individual is in ill health, should be at 6 A. M. This not only proves invaluable in economizing time, but paves the way for regularity in eating, which we will now consider.