The hypothesis which I suggested in _Phantasms of the Living_ itself, in my "Note on a possible mode of psychical interaction," seems to me to have been rendered increasingly plausible by evidence of many kinds since received; evidence of which the larger part falls outside the limits of this present work. I still believe--and more confidently than in 1886--that a "psychical invasion" does take place; that a "phantasmogenetic centre" is actually established in the percipient's surroundings; that some movement bearing some relation to space as we know it is actually accomplished; and some presence is transferred, and may or may not be discerned by the invaded person; some perception of the distant scene in itself is acquired, and may or may not be remembered by the invader. But the words which I am here beginning to use carry with them associations from which the scientific reader may well shrink. Fully realising the offence which such expressions may give, I see no better line of excuse than simply to recount the way in which the gradual accretion of evidence has obliged me, for the mere sake of covering all the phenomena, to use phrases and assumptions which go far beyond those which Edmund Gurney and I employed in our first papers on this inquiry in 1883. When in 1882 our small group began the collection of evidence bearing upon "veridical hallucinations"--or apparitions which coincided with other events in such a way as to suggest a causal connection--we found scattered among the cases from the first certain types which were with difficulty reducible under the conception of telepathy pure and simple--even if such a conception could be distinctly formed. Sometimes the apparition was seen by more than one percipient at once--a result which we could hardly have expected if all that had passed were the transference of an impression from the agent's mind to another mind, which then bodied forth that impression in externalised shape according to laws of its own structure. There were instances, too, where the percipient seemed to be the agent also--in so far that it was he who had an impression of having somehow visited and noted a distant scene, whose occupant was not necessarily conscious of any immediate relation with him. Or sometimes this "telepathic clairvoyance" developed into "reciprocity," and each of the two persons concerned was conscious of the other;--the _scene_ of their encounter being the same in the vision of each, or at least the experience being in some way common to both. These and cognate difficulties were present to my mind from the first; and in the above-mentioned "Note on a suggested mode of psychical interaction," included in vol. ii of _Phantasms of the Living_, I indicated briefly the extension of the telepathic theory to which they seemed to me to point.