But, quite apart from such purely "physical" speculations, I can quite conceive that these hands were not "seen" in the ordinary sense of the word at all. The physical eyes may have played some part in their perception, but only a small part. It is quite possible that "hands" of the character here seen were active and functioning upon another plane altogether than the sense plane, and were perceived at the time by a species of _clairvoyance_. What "clairvoyance" is I do not pretend to know (unless spiritism be true, in which case I can quite easily conceive its _modus operandi_), but the mass of evidence in its favour seems to place it quite beyond the pale of doubt. But even if this be not granted, I can quite see how a certain _rapport_ between the sitter and the hand--or the intelligence behind the hand--might easily enable one sitter to perceive it, and not another. Analogies from trance phenomena and even from experimental thought-transference might be drawn here, in favour of such a theory. The whole theory of apparitions at the moment of death depends upon this established _rapport_, since, if it did not exist, and affect the results, the apparition might just as well appear to Tom, Dick, and Harry as to the percipient--and the percipient is such (supposedly) simply by reason of this pre-established _rapport_. There might be, then, a certain _rapport_ between some sitters and a plane of activity upon which such hands manifest, enabling these individuals to see the hands, while prohibiting others from seeing them. The receptivity or capacity might indicate a greater or lesser degree of psychic capacity--they would be "more mediumistic." That is, the more mediumistic the sitter, the more likely would he be to perceive such hands. And of course we all know in this connection that mediums or psychics in a circle will perceive hands and faces and other forms quite invisible to the ordinary observer. The usual recourse in such cases is to assume that the mediums are fraudulently in league with one another; but when unprofessional psychics experience the same sensations (or perceptions) there is good ground for calling a halt, and asking whether or not the sensations were not possibly genuine in the case of the professional medium also.