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October 20, 1923


JAMA. 1923;81(16):1366. doi:10.1001/jama.1923.02650160040017

What is sleep? Any one who attempts to secure an answer from treatises on physiology is likely to find the information unsatisfactory. The problem has for the most part been relegated to the psychologists. Pawlow 1 has remarked that when the physiologist leaves the study of the simpler parts of the central nervous system, which he has investigated by observation of reflexes, and proceeds to the higher parts, especially the cerebral cortex, his methods suddenly change; he tends to introduce psychologic ideas derived from his own consciousness. The consequence seems to have been a paucity of knowledge respecting the cause of sleep, a subject to which Kleitman 2 has lately called attention. Probably the most popular explanation of the mechanism of falling asleep has assumed an anemia of the brain due to fatigue of the vasomotor center at the end of the day's activities. Innumerable schemes to "draw away blood"