Spiritualists commonly assert that photographic phenomena are easier to control than any others, and this is in a sense true. They would be easy to control _IF_ one were allowed to take the necessary precautions. But one is not, and under the conditions which actually prevail at photographic _séances_ the procedure lends itself to fraud more readily, and in more diverse ways, than any other form of mediumistic activity. Photography is a comparatively complicated process, and at every stage there is opportunity for the astute trickster to produce the effect he desires. Part of the proceedings, moreover, _must_ take place in a light which is inimical to accurate observation, and it should not be forgotten that, as a rule, the “sitter” is immobilised and placed _hors de combat_, so to speak, for an appreciable period while his photograph is being taken. (The significance of this will appear later.) The various fraudulent methods which are or may be used and the question of the reliance which should be placed on the statements of those who believe that they have watched the proceedings so carefully as to exclude the possibility of fraud will be discussed at length later in this paper. I may as well say at once, however, that I see no reason for believing that any spirit photographs are, or have ever been, due to any cause other than fraud.[2] But before discussing the various considerations which appear to justify this view I should like to make it clear that I, personally, am very willing to be convinced _if and when adequate evidence is forthcoming_. The question of what kind of evidence should be considered adequate is one which will be easier to answer after the various possibilities of fraud which must be eliminated have been pointed out. So far as I myself am concerned, I am prepared, further, to admit that photographic phenomena appear to me to be less improbable on general _a priori_ grounds than many other alleged events of supposedly supernormal origin. We know that the camera can detect, or rather that the photographic plate is sensitive to, ether waves which produce no effect on the retina of the human eye, and it seems, on the whole, less improbable that “spirits,” if they exist, should produce subtle and relatively minor etheric disturbances of this kind than that they should be responsible for the movements of gross material objects in the way which is often claimed for them.