"Dreams are mysterious things" said Delapine, nervously fingering his cigarette, as soon as the party had reassembled in the next room. "Sometimes the cause is purely physiological. Overstudy, an attack of indigestion, some disturbance of the circulation, or even some physical pressure may cause a dream or a nightmare. But again, there are other dreams widely different from these which often prove prophetic. In these one's real consciousness may be lost in sleep while the subliminal self, the alter-ego which never slumbers nor sleeps, rises to the surface and speaks in no uncertain tones. The mind sees with the startling clearness as if in a vision. Voices are heard as if from another world, while strange figures, and scenes of unknown places slowly rise before the dreamer. I can vouch for this, many a time it has occurred to me. Only the other day I had worked in vain for many hours trying to solve a physical problem, when suddenly I fell asleep, and in a dream I saw the changes take place, and the formula plainly worked out before my eyes. So clear was it that when I awoke I was able to copy what my mental vision had seen, and on trying the experiment, I found, to my great delight and relief, that the problem was solved." "My dear Delapine," said Riche, "you surely do not believe in clairvoyance, thought-reading, telepathy, apparitions, and all that sort of thing?" "Why not? Are we to doubt a thing merely because it is contrary to our experience? If you had stated thirty years ago that you would be able to converse with a friend on board a ship nearly four hundred miles away, or that you could see a man's bones in his body, or photograph the contents of a sealed wooden box, would not everyone have declared you mad? And yet these things are being done every day. Why then should the things you have just mentioned be less credible? The evidence in their favour is overwhelming. There is hardly a family in the world but contains some member who has experienced such things. Nay, I will go farther, there is not a tribe in any nation, at any period of the world's history which has not believed in these things. As Abraham Lincoln once said, 'You may fool all men some time, you may fool some men for all time, but you cannot fool all men for all time.' No, sir, the things men laugh at to-day as impossible will be improbable to-morrow, conceivable the day after, and a little later everyone accepts them as a matter of course, and wonders how people could ever have been such fools as to have doubted them." "But what evidence is there," said Riche, "that these apparitions and marvellous phenomena really occur? Why are séances held in the dark, or in merely a dull red light? If the performers were not tricksters could they not show these things in full daylight?" "Permit me to ask you one question, my dear doctor," said Delapine. "Why do you develop your photographic plate in the dark and not in broad daylight?"