From the solitary desert Up to Bagdad, came a simple Arab; there amid the rout Grew bewildered of the countless People, hither, thither, running, Coming, going, meeting, parting, Clamour, clatter, and confusion, All around him and about. Travel-wearied, hubbub-dizzy, Would the simple Arab fain Get to sleep,--"But then on waking, How," quoth he, "amid so many Waking, know myself again?" So, to make the matter certain, Strung a gourd about his ankle, And, into a corner creeping, Bagdad and himself and people Soon were blotted from his brain. But one that heard him and divined His purpose, slyly crept behind; From the sleeper's ankle clipping, Round his own the pumpkin tied, And laid him down to sleep beside. By and by the Arab waking Looks directly for his signal-- Sees it on another's ankle-- Cries aloud, "Oh, good-for-nothing Rascal to perplex me so, That by you I am bewildered, Whether I be I or no! If _I_--the pumpkin why on you! If _You_--then where am I, and who?" One can quite appreciate the tangled state of our Arab's mind on awakening under such peculiar circumstances, and, from the point of view of common sense and common experience, such an awakening would be an utter impossibility--fit only for fairy tales and the traditions of savage tribes. Yet, in our own day, here in civilized New York and London, similar cases have been recorded and studied by experts! Under peculiar circumstances, patients have gone to sleep one person and awakened another; and they have remained another, not only during the first temporary moments of bewilderment, but sometimes for days, weeks, and months at a time; and in some cases even whole years have elapsed before the first "self" returned to tenant the body, to look out of the eyes it had looked out of years before; to take up the self-conscious life it had lain down in sleep. And to this there may be the added horror that, during the intervening period of oblivion (for this Self) the same external body, actuated by another "Self," may have performed actions and lived a course of life utterly at variance with the tastes and desires of the primary "Self." The other Self may even have married the common body in the interval--to a man whom the original self had never known--does not know now! There may even have been children; friends, environment, all, all may have been changed in the interim. Like Rip van Winkle, the setting of life may be found to have altered; but in some of these cases, the awakening must be the greater nightmare. The unfamiliarity, even horror, of the situation can be imagined. Yet many such cases exist; and the two Selves alternately usurp and manipulate a common body; the Real Self and the Stranger. Who and what is this Stranger? Apparently it is an alien spirit--another soul,