摘要
Whether sleep is brought on by sleep-inducing substances accumulated naturally in the brain is a question that has attracted more and more attention. Pieron (1910) first reported that normal dogs would sleep for several hours after the transfusion of cerebrospinal fluid (CSF) of sleep-deprived dogs. Pappenheimer et al. (1965—1978) isolated from CSF of goats and sheep a sleep-promoting substance (m.w. ～ 500)
