Though they belong to the same order, I will not here mention the exploits of what the Germans call the Poltergeist, which take the form of flinging stones, ringing bells, turning mattresses, upsetting furniture and so forth. These matters are always open to suspicion and really appear to be nothing but quaint frolics of hysterical subjects or of mediums indulging their sense of humour. The manifestations of the Poltergeist are fairly numerous and the reader will find several instances in the Proceedings and especially in the Journal of the S. P. R. As for communications with the dead, I devoted a whole chapter to these in my own essay entitled Our Eternity and will not return to them now. It will be enough to recall and recapitulate my general impression, that probably the dead did not enter into any of these conversations. We are here concerned with purely mediumistic phenomena, more curious and mere subtle than those of table-rapping, but of the same character; and these manifestations, however astonishing they may be, do not pierce the terrestrial sphere wherein we are imprisoned. 3 Setting aside the religious hypotheses, which we are not examining here, for they belong to a different order of ideas,[1] we find, as an explanation of the Majority of these phenomena, or at least as a means of avoiding an absolute and depressing silence in regard to them, two hypotheses which reach the unknown by more or less divergent paths, to wit, the spiritualistic hypothesis and the mediumistic hypothesis. The spiritualists, or rather the neospiritualists or scientific spiritualists, who must not be confused with the somewhat over-credulous disciples of Allan Kardec, maintain that the dead do not die entirely, that their spiritual or animistic entity neither departs nor disperses into space after the dissolution of the body, but continues an active though invisible existence around us. The neospiritualistic theory, however, professes only very vague notions as to the life led by these discarnate spirits. Are they more intelligent than they were when they inhabited their flesh? Do they possess a wider understanding and mightier faculties than ours? Up to the present, we have not the unimpeachable facts that would permit us to say so. It would seem, on the contrary, if the discarnate spirits really continue to exist, that their life is circumscribed, frail, precarious, incoherent and, above all, not very long. To this the objection is raised that it only appears so to our feeble eyes. The dead among whom we move without knowing it struggle to make themselves understood, to manifest themselves, but dash themselves against the inpenetrable wall of our senses, which, created solely to perceive matter, remain hopelessly ignorant of all the rest, though this is doubtless the essential part of the universe. That which will survive in us, imprisoned in our body, is absolutely inaccessible to that which survives in them.