To sleep or not to sleep! That is the question. In all the world there is nothing to equal it in importance,--to the man with insomnia. His days are mere interludes between troubled nights spent in restless tossing to and fro and feverish worry over the weary day to come. His mind filled with ideas about the disastrous effects of insomnia, he imagines himself fast sliding down hill toward the grave or the insane-asylum. It is true that his conversation very often politely begins something like this: "Good morning. Did you sleep well last night?" but if we fail to respond by an equally polite "and I hope you had a good night?" he seems restless until he has somehow disillusioned us by stating the exact number of hours and minutes during which he was able to lose himself in slumber. We must not ridicule the man who doesn't sleep. We are all very much alike. If any one of us happens to lie awake for a night or two, he is likely to get into a panic, and if the spell should last a week, he begins looking up steamship agents and talking of voyages to Southern seas. The fact is that most people are dreadfully afraid of insomnia. Knowing the effects of a few nights of enforced wakefulness, and having had a little experience with the fagged feeling after a restless night, they believe themselves only logical when they fall into a panic over the prospect of persistent insomnia. =Two Kinds of Wakefulness.= As a matter of fact, insomnia is a phantom peril. There is not the slightest danger from lying awake nights, provided one is not kept awake by some irritating physical stimulus. All fear of insomnia is based on ignorance of the difference between enforced wakefulness and deliberate wakefulness, or insomnia. The man who has acquired the habit may stay awake almost indefinitely without appreciable harm, but the one who is kept awake for a week by a pain, by a chemical poison from infection, or by the necessity for staying up on his job, may easily be in a state of exhaustion. Even in cases of prolonged pain or over-exertion, the body tends to maintain its equilibrium by hastening its rate of repair and by falling asleep before the danger point is reached. It is almost impossible to impair permanently the tissue of the brain except in the presence of a chemical irritant. In case of infection we often have to give medicine to neutralize the effect of the poison or to resort to narcotics which make the brain cells less susceptible to irritation. But nervous insomnia is another story. A HARMLESS HABIT