These last words--control and possession--remind us of the great mass of vague tradition and belief to the effect that spirits of the departed may exercise such possession or control over the living. To those ancient and vague beliefs it will be our task in the next chapter to give a form as exact and stable as we can. And observe with how entirely novel a preparation of mind we now enter on that task. The examination of "possession" is no longer to us, as to the ordinary civilised inquirer, a merely antiquarian or anthropological research into forms of superstition lying wholly apart from any valid or systematic thought. On the contrary, it is an inquiry directly growing out of previous evidence; directly needed for the full comprehension of known facts as well as for the discovery of facts unknown. We need, (so to say), to analyse the spectrum of helium, as detected in the sun, in order to check and correct our spectrum of helium as detected in the Bath waters. We are obliged to seek for certain definite phenomena in the spiritual world in order to explain certain definite phenomena of the world of matter. CHAPTER IX TRANCE, POSSESSION, AND ECSTASY Vicit iter durum pietas. --VIRGIL. _Possession_, to define it for the moment in the narrowest way, is a more developed form of Motor Automatism. The difference broadly is, that in Possession the automatist's own personality does for the time altogether disappear, while there is a more or less complete _substitution_ of personality; writing or speech being given by a spirit through the entranced organism. The change which has come over this branch of evidence since the present work was first projected, in 1888, is most significant. There existed indeed, at that date, a good deal of evidence which pointed in this direction,[194] but for various reasons most of that evidence was still possibly explicable in other ways. Even the phenomena of Mr. W. S. Moses left it possible to argue that the main "controls" under which he wrote or spoke when entranced were self-suggestions of his own mind, or phases of his own deeper personality. I had not then had the opportunity, which the kindness of his executors after his death afforded to me, of studying the whole series of his original note-books, and forming at first-hand my present conviction that spiritual agency was an actual and important element in that long sequence of communications. On the whole, I did not then anticipate that the theory of possession could be presented as more than a plausible speculation, or as a supplement to other lines of proof of man's survival of death.