It would, however, be unjust to assert that all these apparitions are open to question. For instance, it is impossible to deny the reality of the celebrated Katie King, the double of Florence Cook, whose actions and movements were rigorously investigated and controlled by a man like Sir William Crookes for a period of three years. But, looked upon as a proof of survival—notwithstanding that Katie King professed to be a dead person who had returned to earth to expiate certain sins—her manifestations are not so valuable as the communications obtained since her time. In any case, they bring us no revelation concerning existence beyond the grave; and Katie, who was so young, so much alive, whose pulsations could be counted, whose heart was heard beating, who was photographed, who distributed locks of her hair to those present, who replied to every question put to her, Katie herself never uttered a word on the subject of the secrets of the next world. ----- 2 As concerns the manifestations of the first category, it is, of course, impossible to give even a summary account of the most striking of them in these pages; and I refer the reader to the volumes of the _Proceedings_. It is enough to remember that numerous apparitions of deceased persons have been investigated and studied by men of science like Sir William Crookes, Alfred Russel Wallace, Robert Dale Owen, Professor Aksakof, Paul Gibier and others. Gurney, who is one of the classics of this new science, gives two hundred and thirty instances of this sort; and, since then, the _Journal_ of the S.P.R. and the spiritualistic reviews have never ceased to record new ones. It appears therefore to be as well established as a fact can be that a spiritual or nervous shape, an image, a belated reflexion of life is capable of subsisting for some time, of releasing itself from the body, of surviving it, of traversing enormous distances in the twinkling of an eye, of manifesting itself to the living and, sometimes, of communicating with them.