“If you forget a thing, you lose just that much of yourself, don’t you? When you sleep, you enter a world of dreams. In that world you think, speak, go through a set of vivid experiences. Awake, you are aware that you have had these vivid experiences—and yet, you can’t possibly remember them. You are dimly conscious that you were in another world and that while there you thought, suffered, rejoiced, much in the same way that you do here. At times you have a vague feeling that you have undergone some important crisis in your dream-existence, or you wake up with the sensation of having reached some high peak of happiness. But you cannot recall the details, or even the general outlines, of what has happened. Not a scene of this dreamland, of which you are an occasional inhabitant, can you picture to your waking thought; nor does your waking memory hold the visage, or even the name, of one of your dream-associates.”

“All this has to do with dreams,” objected David. “It is admittedly unreal.”

“Don’t rely too much on old definitions. A part of you that sleeps now does experience this dream-life and finds it real. The trouble is, this dream part of you forgets; it is unable to report to the waking personality what it has seen.

“But it is not only in sleep that this dream-personality takes the place of that which we call the real self. The opium-eater inhabits a world, opened to him by his drug, and closed, even to his memory, when the effects of that drug wear off. Then, there is that curious phase of dipsomania in which the victim, apparently possessed of all his faculties, goes through actual experiences—travels, talks with people, transacts business—and when he recovers from his fit of intoxication finds it impossible to remember a single circumstance of the many known to him while under the sway of alcohol. The phenomena of hypnotism give instances of similar independent mental divisions in a single human personality. All this is the familiar material of modern psychology, out of which the scientists build strange and varied theories. I call these divided, or lost, personalities ‘ghosts.’”

“Ghosts of the living, not of the dead.”

“More uncanny than the old-fashioned kind,” mused Una. “Fancy meeting one’s own ghost!”

“Cases of such meetings are on record; Shelley’s, for instance,” said Leighton drily.

“The thing is strange and worth investigating. But,” added David laughingly, “I am not an investigator.”

“It is fascinating,” declared Una emphatically. “Tell us more about it, Uncle Harold. You spoke of an experiment——”

“The experiment, by all means,” said David. “Just what is it?”