This section of the book is from "The Complete Herbalist" by Dr. O. Phelps Brown. Also available from Amazon: The Complete Herbalist: The People Their Own Physicians By The Use Of Nature's Remedies.
Sleep is as much a necessity to the existence of all animal organizations as light, air, or any other element incident to their maintenance and healthful development. The constitutional relation of man to the changes of the seasons, and the succession of days and nights, implies the necessity of sleep. Natural or functional sleep is a complete cessation of the operations of the brain and sensory nervous ganglia, and is, therefore, attended with entire unconsciousness. Thoroughly healthy people, it is believed, never dream. Dreaming implies imperfect rest--some distubing cause, usually gastric irritation, exciting the brain to feeble and disordered functional action. Individuals of very studious habits, and those whose labors are disproportionately intellectual, require more sleep than those whose duties or pursuits require more manual and less mental exertion. The waste of nervous influence in the brain of literary or studious persons requires a longer time to be repaired or supplied than in those even who endure the largest amount of physical toil, without particular necessity for active thought while engaged in their daily manual pursuits. But no avocation or habit affects this question so much as the quality of the ingesta. Those who subsist principally upon a vegetable diet, it is said, require less sleep than those who subsist on both animal and vegetable food. It seems certain that herbivorous animals sleep less than the carnivorous; while the omnivora require more sleep than the herbivora and less than the carnivora. Man, therefore, partaking most of the omnivorous, living on a mixed diet of animal and vegetable food, requires more sleep than the ox, the horse, or the sheep, but much less than the lion, the tigr, or the bear.
Physiologists are not well agreed respecting the natural duration of sleep. Indeed, no positive rule can be laid down on this subject; the statute of Nature, however, appears to read: Retire soon after dark, and arise with the first rays of morning light; and this is equally applicable to all climates and all seasons, at least in all parts of the globe proper for human habitations, for in the cold season, when the nights are longer, more sleep is required.
History shows that those who have lived the longest were the longest sleepers, the average duration of sleep being about eight hours. The time of sleep of each individual must depend on his temperament, manner of life, and dietetic habits. For instance, John Wesley, with an active nervous temperament and a rigidly plain vegetable diet, and who performed an immense amount of mental and bodily labor, slept but four or five hours out of the twenty-four; while Daniel Webster, with a more powerful frame but less active organization, and living on a mixed diet, had a "talent for sleeping" eight or nine hours. Benjamin Franklin used to say that seven hours sleep was enough for any man, eight hours for a woman, and nine hours for a fool! Nevertheless, the invariable rule for all whose habits are correct, is to retire early in the evening, and sleep as long as the slumber is quiet, be the time six, seven, eight, or nine hours. Those who indulge in late suppers, or eat heartily before retiring, are usually troubled with unpleasant dreams, nightmare, and are oftentimes found dead in the morning. Restless dozing in the morning is exceedingly debilitating to the constitution. Persons addicted to spirituous liquors and tobacco, in connection with high-seasoned food, are in danger of oversleeping even to the extent of very considerably increasing the stupidity and imbecility of mind, and indolence and debility of body naturally and necessarily consequent upon those habits. Sleeping in the daytime, or after meals, is not a natural law of the physiology of man. No one requires to sleep after a meal unless he has eaten more food than his system required. Sleep may be indulged in during the day when sufficient sleep is not had at night; but this sleeplessness at night need seldom occur were our habits made conformable to the general hygienic requirements of Nature. Children may sleep all they are inclined to. The position of the body is of some importance. It should be perfectly flat or horizontal with the head, a little varied by a small pillow. Sleeping with the head elevated by two or three pillows or bolsters is certainly a bad habit. The neck is bent, the chest is compressed, and the body unnaturally crooked. Children are made round-shouldered from their heads being placed on high pillows. The beds should be made of straw, corn-husks, hair, various palms and grasses, never of feathers, which can only be mentioned in reprehension. The bed-clothing should always be kept scrupulously clean, and adapted to the season of the year, while the bed-rooms should always be sufficiently large and airy as best conducive to sound sleep and general vigorous health.