But, as usual, the empirical test of experience is the best. Considerations such as those outlined above may be valuable in establishing _a priori_ probabilities, but it is far more important to ascertain whether _as a matter of fact_ people actually do make false recognitions with any frequency. The answer to this has already been given by Mr. Patrick in his account of the Buguet case above.[12] The most striking feature of the case, as he rightly points out, was the way in which witnesses swore to having “unmistakably recognised” the extras they obtained, _and stuck to their recognitions in spite of Buguet’s own confession of fraud and his description of the methods employed_. In the face of this sort of thing, who will be bold enough to maintain that the recognition factor can be assigned any appreciable weight? VIII.--RECENT LITERATURE (W. WHATELY SMITH) Recent contributions to the literature of spirit photography are not very numerous. I may first mention the very thorough exposure by Dr. Walter Prince of the Keeler-Lee-Bocock photographs; this appeared in the _Proceedings_ of the American Society for Psychical Research, vol. xiii., part II, March, 1920. Keeler is a photographic medium who has practised in the United States for a number of years. For the benefit of Mrs. Lee he produced, at a price, a long series of “spirit” photographs purporting to represent the deceased Mr. Bocock in a variety of situations. Test conditions were either wholly absent or absurdly inadequate, and the photographs are, on internal evidence alone, so palpably fraudulent that it is surprising that they were ever accepted at all. The most obvious indication of fraud is the fact that through a whole long series of photographs Mr. Bocock’s facial angle remains the same and identical with that of one of the only two extant photographs of him, no matter what his posture may be or on what occupation he may be represented as engaged. This circumstance clearly points to the use of a single photograph of Mr. Bocock as the basis of all the fakes. The case is not of sufficient importance to be worth discussing at length, but it is an interesting example of the art of critically studying internal evidence and of the almost incredible effrontery of fraudulent mediums. More important is Mr. Edward Bush’s “Spirit Photography Exposed,” a small pamphlet published by the author as a contribution to the “Nehushtan Crusade.” The object of the latter movement, of which one gathers that Mr. Bush is the leading spirit, is to show that all the physical phenomena of Spiritualism are fraudulent and to expose dishonest mediums. This last object, at least, is admirable, and Mr. Bush is certainly entitled to consider himself “one up” on Hope in the matter of spirit photographs.