In these experimental apparitions, which form, as it were, the _spolia opima_ of the collector, we naturally wish to know all that we can about each detail in the experience. Two important points are the _amount of effort_ made by the experimenter, and the degree of his _consciousness of success_. The amount of effort in Mr. S. H. B.'s case (for instance) seems to have been great; and this is encouraging, since what we want is to be assured that the tension of will has really some power. It seems to act in much the same way as a therapeutic suggestion from the conscious self; one can never make sure that any given self-suggestion will "take"; but, on the whole, the stronger the self-suggestions, the better the result. It is therefore quite in accordance with analogy that a suggestion from without, given to a hypnotised person, should be the most promising way of inducing these self-projections. It should be strongly impressed on hypnotised subjects that they can and must temporarily "leave the body," as they call it, and manifest themselves to distant persons--the consent, of course, of both parties to the experiment having been previously secured. Of this type were Dr. Backman's experiments with his subject "Alma,"[128] and although that series of efforts was prematurely broken off, it was full of promise. There were some slight indications that Alma's clairvoyant excursions were sometimes perceptible to persons in the scenes psychically invaded; and there was considerable and growing evidence to her own retention in subsequent memory of some details of those distant scenes. By all analogy, indeed, that subsequent memory should be an eminently _educable_ thing. The carrying over of recollections from one stratum of personality into another--as hypnotic experiment shows us--is largely a matter of patient suggestion. It would be very desirable to hypnotise the person who had succeeded in producing an experimental apparition, of Mr. S. H. B.'s type, and to see if he could then recall the psychical excursion. Hypnotic states should be far more carefully utilised in connection with all these forms of self-projection.