To the minds of many people insomnia is one of the most serious ills to which human nature is heir. Most of this quite false impression is due to the sensational cultivation of dreads with regard to insomnia by newspapers and in general conversation. If we were to credit such impressions, there is a certain number of unfortunates who, for some unknown reason, find it impossible to sleep and who, night after night, drag out the weary hours wooing sleep that does not come, until when daylight dawns they are in despair, distracted by lack of rest. This is presumed to occur night after night, until finally the worn-out mind succumbs to the intolerable anguish of being kept constantly on the rack of wakefulness and the patient becomes insane or saves himself from that by suicide. No wonder, then, that many a one of these patients takes to the use of habit-forming drugs to produce sleep. These, though effective only to a small degree, soothe him for the time, but finally render him such a wreck that there is not even will power enough for him to take his own life and end his intolerable suffering.

Such gruesome pictures of the awful effects of insomnia run rife and produce dreads in the community until just as soon as the ordinary nervous supersensitive person loses an hour or two of sleep two or three nights in a month, he begins to conjure up the specter of insomnia with its awful terrors and still more awful possibilities, and begins to bewail the fate that has chosen him as an unfortunate victim. This exaggerated dread that slight losses of sleep, for which there are often excellent reasons, will develop into an incurable condition of persistent wakefulness has more to do than any other single factor with the production of the state called insomnia which is, however, never half as bad as it is pictured.

Absolute Sleeplessness.—A certain number of patients insist that they sleep very little at night and some tell their friends and even their physicians quite ingenuously that they sleep none at all, and that this has been the case with them for a prolonged period. Practically every physician has heard such stories, and at the beginning of his professional career has usually wondered how the patients continued to live and enjoy reasonably good health in spite of the lack of absolutely necessary brain cell rest. After the physician has the opportunity to investigate some of these stories he understands them better. Patients in hospital, who insist that they are wakeful all the night, prove usually when faithfully watched by a nurse to be wakeful for an hour or two at the beginning of the night and then to sleep for hours at a time, and all of them sleep for intervals more or less prolonged, though they may wake a number of times during the night and may think that they have not been asleep because they hear the clock regularly or some other recurring noise. It is improbable that patients ever spend several nights in succession without sleep and their story is only an index of the persuasion that they are under that they do not sleep, though they are having so many thoroughly restful intervals that their brain cells suffer but little from {652} the need of sleep. Indeed, the principle source of nervous wear and tear for them consists in their persuasion that they do not sleep and the resultant impelling suggestion that a breakdown must before long be inevitable.

Individual Differences.—There are too many safeguards in nature's ordinary dealings with human beings for us to think that people can pass many nights absolutely without rest. Brain cells may apparently be very wakeful, they may be quite ready to take up at once and seemingly without a break trains of thought interrupted sometime before, yet somehow they succeed in obtaining their needed rest. In this matter, as is well known, though it needs to be emphasized again for the benefit of nervous individuals, different people have very different needs. Some require many continuous hours of sleep or they soon begin to have symptoms of nervous exhaustion. Others live on only with snatches of sleep at intervals, or with interrupted sleep during a limited portion of the twenty-four hours, yet enjoy good health for many years. A few seem to be able to live in health and strength with but a few hours of sleep. It may possibly be thought that those who are living their lives with a small amount of sleep are drawing drafts on their future vital powers, and that what they make up in intensity of activity now by shortening sleep, they will discount by shortness of life. How utterly untrue this impression is, however, will be best understood from the fact that many of the men who have worked hardest and slept the least number of hours in the day, have lived to be eighty or even ninety years of age and some of them have even been centenarians.

Cell Rest.—The great differences in the brain cells of different individuals in what concerns sleep becomes more readily intelligible when we recall the extreme differences as regards the need of rest of the various cells in the same individual. While the brain cells seem to require for healthy life, as a rule, nearly one-third of the time, and a man who is constantly taking much less than eight hours of sleep is probably hindering rather than helping his productiveness, especially if his work is intellectual, there are cells in the body that need no such amount of rest as this. Peristaltic movements occur in the digestive tract almost constantly, with only short intervals, and these cells get their rest between their movements. Pulmonary cells and tissues must do the same thing, and are able to do it without any special strain being put on them. The extreme example of the lack of need for prolonged rest is found in the heart. Two-fifths of every second the cells of this organ have a rest during the diastole, but during the remaining three-fifths of every second for all of life they must not only be ready to work but actually engaged in it or serious symptoms ensue. The cells in the brain that subtend cardiac and respiratory activity must be even more able to do without rest, since their action is ceaseless during life. By analogy with these it is not difficult to understand that the brain cells which are involved in consciousness should on occasion be able to stand prolonged periods of activity, or at least of wakefulness. Persistent wakefulness does not appeal to us as so surely destructive after this consideration.

Solicitude Over Sleep.—For those who are much disturbed by the loss of even slight amounts of sleep and who are prone to complain rather bitterly if they are not able to get more than five or six hours a night, I find it a useful preliminary to any more formal treatment of their so-called insomnia {653} to recall the examples of some of the great workers who succeeded in accomplishing marvelously good work though they took much less sleep than the amount the patient secures, yet seems to think inadequate. In spite of such lack of sleep, these workers lived to advanced old age. There are many well-authenticated illustrations of this in recent times. Perhaps the most striking testimony to the power of the human mind to continue work without requiring the refreshment of sleep, except for very short periods, is that of Humboldt, the great traveller, scientist writer and diplomat. Max MÜller, in his autobiography tells the story. It was when he himself was about forty. Humboldt said to him: "Ah! Max, when I was your age I had time to accomplish something, now I find that I must take at least five hours of sleep every night." At the moment Humboldt was over eighty. MÜller said to him: "But, Your Excellency, how much sleep, then, did you take when you were my age?" "Oh!" he said, "I used to turn the light down, throw myself on the lounge for a couple of hours, and then get up and go on with my work again." Humboldt, after a life full of the hardest kind of work of many kinds, lived well past ninety in the full vigor of his intellectual powers.

There are many other examples that might readily be quoted. The traditions of the University of Berlin contain many illustrations of men who did very little sleeping, yet succeeded in accomplishing an immense amount of work and lived far beyond the Psalmist's limit. Virchow, whom I knew very well, did not take more than four or five hours of sleep on most nights in the year. He would be in the Lower House of the Prussian Legislature, which, like the House of Commons, holds its meetings late at night, until one A. M. or later and would be at his laboratory shortly after seven. There was a tradition at the University of Berlin in my time there of one of the older professors in the theological department who went to bed only every alternate night. He had a forty-eight-hour day for work with a seven-hour break. He lived to the age of eighty-five. I know one of our most distinguished workers in medicine here in America who was so busy and so tired at the end of his day that he could not write his book. He would fall asleep on his chair at his desk to wake up only when the milkman came in the morning. He had constructed for himself a special stool without back or sides, shaped like a bench, so that whenever he fell asleep on it he fell off. The fall would wake him up and he would then go on with his work for some hours. He did this sort of thing for many years, and yet he is alive and in the full possession of intellectual health at the age of eighty-three. He learned this expedient from a German professor of medicine who told him of it and at the same time told him that it was no uncommon practice among German professors. Indeed, most of the famous long-livers of the nineteenth century were also well known for the small amount of sleep they required, and apparently there is no need of being anxious lest loss of sleep should prove serious, unless one is adding to whatever detriment to health it may be by worrying about it find so setting two damaging factors at work.