Sleep

a condition of the body in which the nerves rest and cease to carry impressions to the brain or to convey orders. One who is soundly asleep neither sees, hears, tastes, nor feels. If a sensation be violent enough to set the nerves in action, the sleeper is awakened. During sleep, the mind is not conscious. Any action of the body is involuntary. The heart continues to beat, for its action is involuntary-not dependent on the will of the owner. Any circumstance that tends to lessen the sense impressions induces slumber. A slight monotonous circumstance, such as the faint chirp-chirp of a cricket, that attracts the attention and causes the mind to leave other matters and forget its problems, leads to slumber. Cases are on record of prisoners lulling their guards to sleep by some such device. The lullaby song and the slow swing of the cradle act on this principle. Artificial sleep may be caused by certain drugs. The poppy is the plant of sleep. All animals having nervous systems require sleep. Most flesh-eating animals sleep in the daytime and prowl at night. Moths fly abroad at night and rest in the daytime. Man sleeps naturally at night. Those whose occupations require night work testify that sleep in the daytime, even under the most favorable conditions, is not so refreshing. Children require more sleep than adults; fleshy people more than slender people. Outdoor employment and exercise in cold air lead to drowsiness. Adults require to sleep rather less than a third of their time. Sleep has not failed to attract the notice of poets:

Death is an eternal sleep.-Inscription on the gate of a French cemetery.