It was one of those moments in which a doubt which one had thought for ever abolished grips the most unbelieving. For the first time, perhaps, he looked around him with uncertainty and wondered in what world he was. As for the faithful adherents of the unknown, who had long understood that we must resign ourselves to understanding nothing and he prepared for every sort of surprise there was here, all the same, even for them, a mystery of another character, a bewildering mystery, the only really strange mystery, more torturing than all the others together, because it verges upon ancestral fears and touches the most sensitive point of our destiny. 4 The spiritualistic argument most worthy of attention is that supplied by the apparitions of the dead and by haunted houses. We will take no account of the phantasms that precede, accompany or follow hard upon death: they are explained by the transmission of a violent motion from one subconsciousness to another; and, even when they are not manifested until several days after death, it may still he contended that they are delayed telepathic communications. But what are we to say of the ghosts that spring up more than a year, nay, more than ten years after the disappearance of the corpse? They are very rare, I know, but after all there are some that are extremely difficult to deny, for the accounts of their actions are attested and corroborated by numerous and trustworthy witnesses. It is true that here again, where it is in most cases a question of apparitions to relations or friends, we may be told that we are in the presence of telepathic incidents or of hallucinations of the memory. We thus deprive the spiritualists of a new and considerable province of their realm. Nevertheless, they retain certain private desmesnes into which our telepathic explanations do not penetrate so easily. There have in fact been ghosts that showed themselves to people who had never known or seen them in the flesh. They are more or less closely connected with the ghosts in haunted houses, to which we must revert for a moment. As I said above, it is almost impossible honestly to deny the existence of these houses. Here again the telepathic interpretation enforces itself in the majority of cases. We may even allow it a strange but justifiable extension, for its limits are scarcely known. It has happened fairly often, for instance, that ghosts come to disturb a dwelling whose occupiers find, in response to their indications, bones hidden in the walls or under the floors. It is even possible, as in the case of William Moir,[1] which was as strictly conducted and supervised as a judicial enquiry, that the skeleton is buried at some distance from the house and dates more than forty years back. When the remains are removed and decently interred, the apparitions cease. [1] Proceedings, vol. vi., pp. 35-41.