In an article by me, "_Is Man an Electrical Organism?_" which appeared in _The Nineteenth Century_, July, 1914, I showed--on the evidence of careful and delicate experiments by an electrical expert--that the two sides of the body (and presumably of the brain) are of different electrical potential. The active, right side is _positively_ electrified, while the passive, left side is _negatively_ electrified. Mental Telepathy and Telæsthesia prove, surely, that brain and nerve-currents are electrical--one brain-hemisphere operating as transmitter, the other as receiver. Since Nature employs _one_ Law only to suspend the mighty solar systems of the Universe and to bring an apple to the ground, is it credible that she should employ _two_ laws for "Wireless" and for Human telegraphy, respectively? The Hibernation both of animal and vegetative organisms shows two poles of vital function; Life and Consciousness passing into the Recessive, or potential, mode during such winter-sleep. Plants sleep by night. Is Sleep a recession merely from the state of Consciousness to the potential states of Sub- and Supra-consciousness? And do these two states alternate normally in the opposite halves of the brain, concurrently with the alternation of Day and Night? Night-blindness suggests such an alternation in the dual factors of Vision--which comprises the intrinsic _faculty_ of Vision and the concrete _function_ of visualising the external. Every concrete function normally wanes with the waning of Day. Hence increasing drowsiness, passing into Sleep. Morning and evening mentality differ greatly. Intellect, reason and physical activity are paramount during the day. Emotion and imagination intensify with the approach of night. Is this an alternation in function of the Male and Female brain-hemispheres, coincident with the alternation of the dual luminaries of our earth--the positive, unchanging Dominant Sun; the changeful Moon, with her Recessive phases and her mystical influences upon Life and Mind? The ante-natal life of the embryo is set in terms of lunar months. The word "lunatic" expresses the effects of lunar phases on persons of unstable mentality. Whence do we derive our daily influx of Life? Though we have sunk to rest with dissolution in our bones, we awake re-charged with powers of living--a phenomenon for which Science has no explanation. Life does not originate in vital processes; vital processes originate in Life. Do we, in sleep, when processes have exhausted our daily influx of Life-power, recruit this again from a psychical source? Are living processes the wick of a lamp which is filled with the Spirit of Life at each recurring dawn, spent by the day's endeavour, and re-filled again with the following dawn? Failure of sleep kills more swiftly than starvation. And drug-insensibility will not preserve life unless natural sleep supervene.