Henry IV. Part ii.
Ida. I begin to perceive the importance of this digression on the nature of mind. You wish us to believe, there is a temporary desertion of the spirit from the body, and therefore the body sleeps?
Ev. Not absolute desertion, but a limit to its influence. Many have thought in conformity to your question; and indeed, Ida, it is a belief so holy, that I may feel it to be almost an impiety to differ.
From the time of Aristotle to Haller, the term “Sleep” expresses that condition which is marked by a cessation of certain mental manifestations, coincident with the degree of oppression; for it is an error to say that the body sleeps,—it is the brain only, perhaps I may say, the cerebrum, or the fore lobes; for I believe the lower part of it (that which imparts an energy to the process of breathing and of blood circulation) is never in a complete sleep, but merely in a state of languor, or rather of repose, sufficient for its restoration,—if it were to sleep, death would be the result.
This repose is in contrast with a state of waking, that activity of mind in which ideas are constantly chasing each other like the waves of ocean; the mode of displacing one idea being by the excitement of another in its place.
In that state of sound sleep which overcomes children, whose tender brains are soon tired, or old persons whose brains are worn, and in persons of little reflection,—the mind is perfectly passive, and its manifestations cease.
So writes Professor Stewart,—that there was a total suspension of volition during sleep, as regards its influence over mental or corporeal faculties; and I may even adduce a scrap from Burton, although I am an admirer of the quaint old compiler for little else than his measureless industry:—
“Sleep is a rest or binding of the outward senses, and of the common sense, for the preservation of body and soul. Illigation of senses proceeds from an inhibition of spirits, the way being stopped by which they should come; this stopping is caused by vapours arising out of the stomach, filling the nerves by which the spirits should be conveyed. When these vapours are spent, the passage is open, and the spirits perform their accustomed duties: so that waking is the action and motion of the senses, which the spirits, dispersed over all parts, cause.”
Astr. But is volition always suspended even in sound sleep? Was it not the opinion of Berkley, that the mind even then was percipient? How else can we account for the waking exactly at one predetermined hour? If we retire to sleep at the latest hour, or oppressed with fatigue, so strong an impression is produced in our mind, that the breaking of our sleep is almost at the given moment.
Ev. I will answer you at present, Astrophel, only by analysis; it is not yet time to explain.