“A periodical renewal of the nervous energies as often as once a day is an institution of nature, none the less necessary to the well-being of the animal economy, because in some degree under the control of the will. To disregard its requirements with impunity is no more possible than it is to violate any other organic law with impunity, and no man need flatter himself that he may systematically intrench upon the hours usually devoted to rest and still retain the freshness and elasticity of his faculties. With the same kindliness that marks all the arrangements of the animal economy, this condition is attended with many pleasing sensations and salutary effects, gently alluring us to seek the renovation which it offers. ‘While I am asleep,’ says the immortal Sancho Panza, ‘I have neither fear nor hope; neither trouble nor glory; and blessings on him who invented sleep,--the mantle that covers all human thoughts; the food that appeases hunger; the drink that quenches thirst; the fire that warms; the cold that moderates heat; and, lastly, the general coin that purchases all things; the balance and weight that make the shepherd equal to the king and the simple to the wise.’ The ill effects of insufficient sleep may be witnessed on some of the principal organic functions, but it is the brain and nervous system that suffer chiefly and in the first instance. The consequences of a too protracted vigil are too well known to be mistaken, and many a person is suffering, unconscious of the cause, from the habit of irregular and insufficient sleep. One of its most common effects is a degree of nervous irritability and peevishness, which even the happiest self-discipline can scarcely control. That buoyancy of the feelings, that cheerful, hopeful, trusting temper that springs far more from organic conditions than from mature and definite convictions, give way to a spirit of dissatisfaction and dejection; while the even demeanor, the measured activity, are replaced either by a lassitude that renders any exertion painful, or an impatience and restlessness not very conducive to happiness. Upon the intellectual powers the mischief is still more serious. They not only lose that healthy activity which combines and regulates their movements in the happiest manner, but they are no longer capable of movements, once perfectly easy. The conceptions cease to be clear and well defined, the power of endurance is weakened, inward perceptions are confounded with outward unhappiness, and illusory images obtrude themselves unbidden upon the mind. This kind of disturbance may pass sooner or later into actual insanity, and many a noble spirit has been utterly prostrated by habitual loss of rest.”