CHAPTER XV. SLEEP. The ideal form of rest for body and mind is sleep, for during it the muscles are completely relaxed, the heart beats quietly, the functions of the various organs are suspended to a very large degree, and the brain is in oblivion. This question is one of paramount importance. The individual who neglects to secure the requisite amount of sleep is committing a crime against himself, for which he will have to pay the penalty sooner or later. The experience of centuries has proved that the average man or woman needs eight hours of it daily, and that means that they ought to be in bed for eight and a half hours. [Sidenote: Beauty sleep.] It is not sufficient that these eight hours should be taken at any time of the day or night that happens to be convenient. The old idea of “beauty sleep” is perfectly correct, for there is no rest equal to that obtained during the first part of the night, and no amount of lying in bed in the morning can make up for the loss of it. Ask anyone who has to work at night, nurses, doctors or workmen on night shift, and they will tell you without any hesitation that such work takes twice as much out of them as a corresponding amount by day. They will also declare, if you inquire further, that the sleep they get in the daytime is not half so refreshing as that obtained during the night. Human strength ebbs and flows with the regularity of the tides, with the difference that the rise and fall occurs once instead of twice in the twenty-four hours. The system is at its best from about six in the morning until the evening. It is at its worst from about eleven at night until four in the morning, and during those hours, if people are awake, either at work or at play, and even if they have had abundance of sleep during the course of the day, the heart tends to flag, and all the powers and faculties are lowered. It is on that account that people who have to sit up all night begin to feel chilly and tired in the dead of night, even though the room itself may be quite warm. They feel cold and uncomfortable, simply because their whole systems are depressed. It is for the same reason that people who are ill are almost always worse during these hours. To sit up night after night, even with plenty of rest in the daytime, is wearing to the system. To do it without that daily rest would speedily cause a collapse. And people who habitually sit up later than they should do, not going to bed until midnight or after, are in danger of bringing about the same catastrophe, only in a slower manner. There is a measure of excitement about these late hours which makes them alluring. Many people say that they can work or write more easily or play cards with greater zest then than at any other time, but it is a false form of stimulant, for which the system has to pay a heavy price later on. [Sidenote: Remedies for sleeplessness.]