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.