Another indication of the subliminal power at work to produce these hallucinations is their remarkable range—a range as wide, perhaps, as that over which therapeutic effects are obtainable by suggestion. The post-hypnotic hallucination may affect not sight and hearing alone (to which spontaneous hallucinations are in most cases confined), but all kinds of vaso-motor responses and organic sensations—cardiac, stomachic, and the like—which no artifice can affect in a waking person. The legendary flow of perspiration with which the flatterer sympathises with his patron's complaint of heat—si dixeris "Æstuo," sudat—is no exaggeration if applied to the hypnotic subject, who will often sweat and shiver at your bidding as you transplant him from the Equator to frosty Caucasus.
Well, then, given this strength and vigour of hallucination, one sees a possible extension of knowledge in more than one direction. To begin with, by suggestion to the subject that he is feeling or doing something which is beyond his normal range of faculties, we may perhaps enable him to perceive or to act as thus suggested.
What we need is to address to a sensitive subject a series of strong suggestions of the increase of his sensory range and power. We must needs begin by suggesting hallucinatory sensations:—the subject should be told that he perceives some stimulus which is, in fact, too feeble for ordinary perception. If you can make him think that he perceives it, he probably will after a time perceive it; the direction given to his attention heightening either peripheral or central sensory faculty. You may then be able to attack the question as to how far his specialised end-organs are really concerned in the perception;—and it may then be possible to deal in a more fruitful way with those alleged cases of transposition of senses which have so great a theoretical interest as being apparently intermediate between hyperæsthesia and telæsthesia or clairvoyance. If we once admit (as I, of course, admit) the reality of telæsthesia, it is just in some such way as this that we should expect to find it beginning.
I start from the thesis that the perceptive power within us precedes and is independent of the specialised sense-organs, which it has developed for earthly use.
νοὑς ὁρα καἱ νοὑς ἁκοὑει τἁλλα κωφἁ καἱ τυφλα.
I conceive further that under certain circumstances this primary telæsthetic faculty resumes direct operations, in spite of the fleshly barriers which are constructed so as to allow it to operate through certain channels alone. And I conceive that in thus resuming exercise of the wider faculty, the incarnate spirit will be influenced or hampered by the habits or self-suggestions of the more specialised faculty; so that there may be apparent compromises of different kinds between telæsthetic and hyperæsthetic perception,—as the specialised senses endeavour, as it were, to retain credit for the perception which is in reality widening beyond their scope.
In this attitude of mind, then, I approach the recorded cases of transposition of special sense.[83]
Two main hypotheses have been put forward as a general explanation of such cases, neither of which seems to me quite satisfactory. (1) The common theory would be that these are merely cases of erroneous self-suggestion;—that the subject really sees with the eye, but thinks that he sees with the knee, or the stomach, or the finger-tips. This may probably have been so in many, but not, I think, in all instances. (2) Dr. Prosper Despine and others suppose that, while the accustomed cerebral centres are still concerned in the act of sight, the finger-end (for example) acts for the nonce as the end-organ required to carry the visual sensation to the brain. I cannot here get over the mechanical difficulty of the absence of a lens. However hyperæsthetic the finger-end might be (say) to light and darkness, I can hardly imagine its acting as an organ of definite sight.
My own suggestion (which, for aught I know, may have been made before) is that the finger-end is no more a true organ of sight than the arbitrary "hypnogenous zone" is a true organ for inducing trance. I think it possible that there may be actual telæsthesia,—not necessarily involving any perception by the bodily organism;—and that the spirit which thus perceives in wholly supernormal fashion may be under the impression that it is perceiving through some bizarre corporeal channel—as the knee or the stomach. I think, therefore, that the perception may not be optical sight at all, but rather some generalised telæsthetic perception represented as visual, but incoherently so represented; so that it may be referred to the knee instead of the retina. And here again, as at several previous points in my argument, I must refer the reader to what will be said in my chapter on Possession by external spirits (Chapter IX.) to illustrate the operation even of the subject's own spirit acting without external aid.
And now I come to the third main type of the dynamogenic efficacy of suggestion: its influence, namely, on attention, on will, and on character—character, indeed, being largely a resultant of the direction and persistence of voluntary attention.