Dr. Farnham's Lecture.

However much experimenters may differ as to the causes of sleep, and the amount necessary for men under varying circumstances, experience has shown that most of us are in better health when we have a sufficient quantity at regular times. The adaptability of the human system is very great, and is shown very markedly in the matter of sleep. The insane can sustain long continued conditions of sleeplessness. Every organ and tissue in the body must have rest, or they soon become worn out. The heart must make use of the intervals between beats to obtain necessary repose. The cause of sleep is the using up of potential energy. When we are fatigued by excessive mental labor, prolonged sleep will not bring the needed relief. The causes of sleeplessness are, excessive study; underfeeding and improper food; breathing impure air; neglect of exercise; and worry. Strong coffee and tea are productive of insomnia. Alcohol when taken in small quantities, keeps one awake; when taken in large quantities it produces not sleep, but stupor.