EXCITING CAUSES OF SLEEP. 299 be so far out of health as to be justifiably reckoned as dyspeptic, this particular time after a meal, once a day, and the hour or so after breakfast might for many reasons be preferred,-should be chosen as the best for the purpose of bodily exercise. In a much more advanced stage of the digestive processes, when the food has reached the large intestines, it is very often troublesome to the dyspeptic invalid; and when this happens, it proves a common cause of rendering the sleep disturbed or imperfect. How commonly does the dyspeptic awake about two or three o'clock in the morning, in a state of feverish restlessness, with a parched tongue, a dry skin, a burning heat of the palms of his hands and the soles of his feet, and perhaps an obscure sensation of undue sensibility, or perhaps a more marked sense of uneasiness, or even pain, in the bowels? This is usually the consequence of some error in the diet of the previous day; and perhaps in general, of some imperfectly digested article of food that has been eaten at supper : "Oppress not nature sinking down to rest, With feasts too late, too solid, or too full." ARMSTRONG. It has indeed been said by various writers, that the general abandonment of the practice of eating a hearty meal of food at supper time, the heaviest meal having been taken at noon or soon afterwards, may affect the probabilities of sleep disadvantageously. It has been urged, that the interval of four or five hours between the heaviest meal of the day and the time of going to bed, offers by no means the most favourable period for going to rest, or sleeping soundly and tranquilly; that the early stage of digestion is passed over, during which there is the natural tendency to repose; and that when we dine at six P.M., and go to bed at ten or eleven o'clock, we seek to sleep at a time when the system, as respects the influence of the food upon it, is taking up again a more active state, and when active muscular exercise is expedient to forward healthily the latter stages of the digestive process. This would be a good argument, were the time required for sleep limited to the three or four or five hours needful to the primary processes of digestion, and if it were not proved that sleep is apt to hurry these processes unduly, and to lead to their being imperfectly performed. As it is, the eater of suppers may be more likely to sleep during the early hours of the night, but is assuredly more likely to pass the remaining hours of bed-time in broken and imperfect sleep, or in a state of restless wakefulness. So far as the valuable result as to health and physical comfort, of taking the greater part of the required daily sustenance in the earlier part of the day,-making the breakfast and the dinner to be virtually almost the only meals, and taking the dinner as early as may be in the day,-enough has been said in the first chapter; and neither the man of sedentary habits, nor the invalided, should take more food thereafter than consists with satisfying the cravings of the stomach; and the food taken thereafter under these circumstances, should be of the kind that is least EXCITING CAUSES OF SLEEP. 301 likely to derange the economy, by passing in a crude and imperfectly chymified state into the bowels. In cases where the sleepless condition appears to be more or less referable to an undue inanition; and in which, accordingly, the use of food some short time before the bed-time evidently promotes the probability and the perfect character of the sleep, the risk of subsequent intestinal derangement from the passage of crude aliment into the bowels should be kept in view, and the kind of food made use of at supper be looked upon with some degree of jealousy. These, however, are usually cases of long continued disorder of the digestive organs, referable to much unwise neglect of muscular exercise, and often to the further disadvantage of the use of injudicious food, selected to pamper the capricious and defective appetite; the system being unable to assimilate a sufficiency of such ingesta to supply the positive wants of the economy, unless food is taken frequently during the hours when any degree of exertion has to be undergone. The radical treatment of such cases must involve a fuller attention to the means of hygiene; and an exact obedience to the organic laws may commonly render the need of a further supper than a little bread or biscuit to be no longer felt, even for the purpose of securing sleep. The cause of sleeplessness, or of an oppressing, overpowering, and enfeebling sleep, is frequently to be found in the state of the circulation. If the blood is driven with unwonted rapidity through the vessels of the brain, restlessness is very liable to ensue ; and if such rapidity of vascular action is still further increased, that restlessness usually passes into a profound, lethargic sleep, which exhausts and still further deranges the balance of the vital forces, instead of proving to be refreshing and restorative. To render the sleep perfect, the blood must be equally circulated; neither this part nor that being furnished with more than its customary and natural proportion. So far as the effect of the great respiratory function upon the character of the sleep, the importance of a full oxygenation of the blood, to this and all the other processes and necessities of the system, has been previously noticed. The probable consequence of an imperfect aëration of the blood upon the sleep, is to render it imperfect and much disturbed in the first instance, and eventually lethargic. Cases of pulmonary disease, equally with those that are simply dependent on imperfect ventilation of the bed-room, illustrate this. Disturbed function of any of the great secreting organs, almost always either prevents sleep, or renders it imperfect; producing irritation of the nervous system, and interfering with the absolute repose of the intellectual and the motor powers, and in some cases even of the external senses. But the less perfect the sleep, the less of nervous energy does it restore, and the less does it advantage the sleeper : "A sleep without dreams, after a rough day Of toil, is what we covet most."-BYRON. Such deranged condition of the great organs often interferes mechanically with the due passage of the blood through their tissues, and thus obstructing more or less the general circulation, may so far oppress the vascular condition of the nervous centres, as to render the sleep imperfect or lethargic. The mechanical influence of an overloaded state of the bowels, or a congestive condition of the liver, &c., may often sufficiently explain disturbed sleep. In the case of the invalided, sleep may often be induced, or tranquillised, or relieved from its lethargic character, by directing the surface of the body, locally or generally, to be sponged with cold, or tepid, or warm water; by directing the feet and legs to be fomented with warm water; or by directing the application of cloths, wetted with cold or warm water, according to circumstances, to the forehead and temples. These often prove to be sufficiently energetic sedatives, and are simple and safe means of procuring sleep. To secure sleep, then, the mind must be tranquil, its powers moderately used, but not over-worked, and its several faculties kept in proper subjection to one another; the muscles of voluntary motion must be duly exercised; the stomach kept free from disturbing influences; the circulating and respiratory organs, and the several organs of secretion and excretion, must all perform their respective duties without appreciable inconvenience : "Vivitur parvo bene, cui paternum Nec leves somnos timor aut cupido Sordidus aufert."-HOR. Carm., Lib. ii., 16. |