VII

SLEEP AND SOMNAMBULISM.

Authorized Translation by William W. Coles, M.D.

FROM THE FRENCH OF PROF. H. BERNHEIM, NANCY, FRANCE. To say that sleep is due to anæmia or hyperæmia of the brain, to auto intoxication or to a simple cerebral dynamism gives us but an incomplete explanation. All that we know clinically is that after a waking period of varying length a feeling of lassitude comes over us, a sensation of somnolence; we go away by ourselves, our eyelids become heavy; we remain quiet, relax; a pleasant torpor envelopes us and external impressions gradually become effaced. The voluntary intellectual activity is dormant while only the automatic life of the imagination as expressed in dreams is operative. After a varying length of time consciousness gradually returns; external impressions become vaguely evident; we feel again that agreeable torpor which formed the prelude to the sleeping state; a sensation of somnolence which gradually passes away ushers in the reawakening of the intellectual activity but leaves a complete amnesia for the period of sleep except for the recollection of certain dreams which may have passed along the horizon of our consciousness. Only these sensations of somnolence preceding and following the sleeping state and the memory of the dreams indicate to us that we have slept. The objective symptoms are the closed eyes, the relaxed limbs, the apparent unconsciousness of the subject and sometimes the deepened respi

ration.

Still, these subjective and objective symptoms are not sufficient to characterize physiological sleep. The intoxication due to opium, chloral, uremia and acteonæmia of typhoid infection can produce sleep; likewise hysterical or epileptic states. An apoplectic coma resembles a profound sleep but differs in that the individual cannot be awakened. Catatonic stupor often gives the impression of a prolonged sleep. However, anyone affected with the above conditions may have a natural sleep which must be differentiated from the pathological. The functional and organic conditions of the brain must be widely different in the two types, but the differences are unknown to us, for we know nothing of sleep beyond its characteristic unconsciousness with or without dreams. And these dreams, are they characteristic of sleep? They may occur in the somnolent period preceding it or even in the waking state as products of the imagination when the active