§ 9. Before quitting the subject of the development of telepathic phantasms, I may be allowed to point out its relation to the physiological sketch at the close of the tenth chapter; for it happens to supply substantial confirmation to the views of centrifugal origin there maintained. The whole idea of morbid excitation from the more external parts of the sensory apparatus becomes here irrelevant. All that has been said in this chapter as to the development of the hallucination from the nucleus of a transferred impression marks out the higher part of the brain - the part which is concerned with ideas or general images of persons and things, and not with immediate perception of them - as the place where the abnormal process starts; the hallucination itself being due to the downward promulgation of the disturbance from these higher tracts to the specific sensory centre concerned. Especially must this origin commend itself in respect of the phantasms which are bodied forth in a more or less fanciful form, with elements which are clearly the percipient's own contribution, but which he would never have contributed had not telepathy supplied an idea for him to clothe.

But perhaps the cases where the hypothesis is most helpful are those of which Mr. Marchant's (No. 26, p. 149) is the type, where no obvious rapport exists between the two parties concerned. How - we naturally ask - could the idea of Kelsey be impressed on Mr. Marchant's mind with such force as to embody itself in a visible phantom, when Kelsey's mind was presumably not occupied either with Mr. Marchant or with himself in relation to him? From a physiological point of view the fact becomes less startling if we suppose the primary change in Mr. Marchant's brain to take place at the part which is the great storehouse of old impressions; at the part, moreover, where an appropriate physical basis may be found not only for distinct and recognisable images, but for sub-conscious ideas and memories, and for the most distant and intangible associations. In the register of the brain it is seldom that a record, once made, is so utterly obliterated that, under suitable conditions, it may not be revived. And if once a relation be established between two persons, and the records of it registered in their two brains, it may be possible for the same harmony occasionally to manifest itself between those records - even though they be long sunk below the level of conscious attention - as between the immediate impressions of the moment; and, this once granted, we have seen how the physiological process may lead on to the projection of the visible phantom.1 In psychical terms, I see no reason why sub-conscious ideas and memories which are in no distinct way present to consciousness, such as Kelsey's sense of his old relationship to Mr. Marchant, should not evoke similar blind movements in Mr. Marchant's mind, which, gathering strength, might lead him to body forth the vision of his old acquaintance.

A hallucination which is thus initiated by the quickening of long-buried memories, and of dim tracts of emotional association, is the most conspicuous example of the projection of an idea from within outwards; and the tremor to which the sensorium reverberates will presumably start in the inmost penetralia of cerebral process.

1 I have sufficiently emphasised the difficulty of expressing the transmission of telepathic impressions in physical terms (pp. 92-4). And though I here suggest that the difficulty is lessened if we may draw on unconscious parts of the mind, and old records in the brain, my physiological point is independent of this suggestion, and is limited to the percipient's own organism. There certain nervous changes do undoubtedly take place, in correspondence with the psychical fact of the hallucination; and my object is to show that what we observe as to the psychical fact may be best accounted for on a particular view of the physical process.