There is much more, of course, very much more, to say about the working of the machinery of the inside of the body and about the plain common sense needed to keep it well and rested, but I have said enough for now to start a thoughtful mind to work. Now for keeping the body well rested from the outside. It is all so well arranged for us--the night given us to sleep in, a good long day of work and a long night of rest; so the time for rest and the time for work are equalized and it is so happily arranged that out of the twenty-four hours in the day, when we are well, we need only eight hours' sleep. So well does nature work and so truly that she can make up for us in eight hours' sleep what fuel we lose in sixteen hours of activity. Only one-third of the time do we need to sleep, and we have the other two-thirds for work and play. This regular sleep is a strong force in our aim to keep rested. Therefore, the plain common sense of that is to find out how to go to sleep naturally, how to get all the rest out of sleep that nature would give us, and so to wake refreshed and ready for the day. To go to sleep naturally we must learn how to drop all the tension of the day and literally _drop_ to sleep like a baby. _Let go into sleep_--there is a host of meaning in that expression. When we do that, nature can revive and refresh and renew us. Renew our vitality, bring us so much more brain power for the day, all that we need for our work and our play; or almost all--for there are many little rests during the day, little openings for rest that we need to take, and that we can teach ourselves to take as a matter of course. We can sit restfully at each one of our three meals. Eat restfully and quietly, and so make each meal not only a means of getting nourishment, but of getting rest as well. There is all the difference of illness and health in taking a meal with strain and a sense of rush and pressure of work, and in taking it as if to eat that one meal were the only thing we had to do in the day. Better to eat a little nourishing food and eat it quietly and at leisure than a large meal of the same food with a sense of rush. This is a very important factor in keeping rested. Then there are the many expected and unexpected times in the day when we can take rest and so _keep rested._ If we have to wait we can sit quietly. Whatever we are doing we can make use of the between times to rest. Each man can find his own "between times." If we make real use of them, intelligent use, they not only help us to keep rested, they help us to do our work better, if we will but watch for them and use them.