+============================================================+ | Organic Life. | | | Conscious Life. | | | | Imaginative Faculties. | | | | | Coördinative Faculties. | | | | | | Special Sensation and Voluntary Motion.| |----+----+----+----+----+-----------------------------------| |XXXXXXXXXXXXXXXXXXXXXX | Normal life. | |------------------------------------------------------------| |XXXXXXXXXXXXXXXXX |First stage of sleep--Hypnagogic | | | hallucinations. | |------------------------------------------------------------| |XXXXXXXXXXXX |Second stage of sleep--Dreaming. | |------------------------------------------------------------| |XXXXXXX |Third stage of sleep. | |------------------------------------------------------------| |XX |Profound sleep. | |------------------------------------------------------------| |XXXXXXX |First stage of waking. | |------------------------------------------------------------| |XXXXXXXXXXXX |Second stage of waking--Dreams. | |------------------------------------------------------------| |XXXXXXXXXXXXXXXXX |Third stage of waking--Hypnagogic | | | hallucinations. | |------------------------------------------------------------| |XXXXXXXXXXXXXXXXXXXXXX |Complete awakening. | +------------------------------------------------------------+ It was formerly believed that during the time of sleep all the processes of assimilation and nutrition throughout the body are increased,--in short, that it is the season of repair for the waste of tissue incurred during the hours of wakeful activity. While it is true that in sleep the expenditure of force is greatly reduced, the more exact researches of modern physiologists indicate a universal reduction in the rate of all the vital processes. The final result, however, is a general renewal of energy, because the aggregate income of the tissues is greater than their outgo during the suspension of conscious activity. The following observations make very apparent the fact of a reduction of physiological activity: