We are surrounded by unknown forces and there is no proof that we are not also surrounded by invisible beings. Our senses teach us nothing about reality. But logically the discussion of theories ought to be reserved as a complement to the ensemble or summary of our observations and experiments; that is to say, for the last chapter. It behooves us before everything else positively to ascertain that mediumistic phenomena exist. It seems to me, that _this has been done_ for every impartial reader. This will be overwhelmingly confirmed by the following chapters. But there is one point on which we ought to dwell a moment. I mean the question of fraud, conscious or unconscious, which it would be natural, but unfair, to here ignore and cover up. Our judicial review would not be complete did we not consecrate a special chapter to these mystifications, which unhappily are too frequently employed by mediums. CHAPTER V FRAUDS, TRICKS, DECEPTIONS, IMPOSTURES, FEATS OF LEGERDEMAIN, MYSTIFICATIONS, IMPEDIMENTS Several times in the preceding chapters the question has come up of fraud in the mediums. I am sorry to say that experimenters must be constantly on their guard against them. It is this which has discouraged certain eminent men and prevented them from continuing their researches, for their time is too precious to waste. This may be especially noticed in the letter of M. Schiaparelli above (p. 64) whom Spiritualists keep citing (wrongly) as among the number of their partisans. But he absolutely refuses to be identified with them. He accepts no theory; he is not even sure of the actual existence of the facts, and has declined to give the time needed for their authentication. I shall take occasion in the second volume of _The Unknown_ to treat of Spiritualism (properly so called), of the doctrine of the plurality of worlds, of the plurality of existences, of re-incarnation, of pre-existence, and of communications with the departed,--subjects independent of the material phenomena to a discussion of which the present work is devoted. To these subjects the physical manifestations only contribute in an indirect manner. As we have already several times said in the preceding pages, we are only concerned here to _prove the actual existence of these extraordinary phenomena_. The establishing of the proof depends above all upon the elimination of fraud. In the case of Eusapia (the medium most thoroughly examined in the present volume) fraud, unhappily, has been only too well established in more than one instance. But a very important remark must here be made. All physiologists know that hysterical persons have a tendency to falsehood and simulation. They lie, apparently without reason, and solely for the pleasure of lying. There are hysterics among the women and young girls of the higher classes. Does this characteristic defect prove that hysteria does not exist? It proves just the contrary.