“What are termed spirit photographs, the appearance on a photographic plate of other figures besides those of the sitters, often those of deceased friends of the sitters, have now been known for more than twenty years. Many competent observers have tried experiments successfully; but the facts seemed too extraordinary to carry conviction to any but the experimenters themselves, and any allusion to the subject has usually been met with a smile of incredulity or a confident assertion of imposture. It mattered not that most of the witnesses were experienced photographers who took precautions which rendered it absolutely impossible that they were imposed upon. The most incredible suppositions were put forth, by those who only had ignorance and incredulity to qualify them as judges, in order to show that deception was possible. And now we have another competent witness, Mr. Traill Taylor, for many years editor of the _British Journal of Photography_, who, taking every precaution that his life-long experience could suggest, yet obtained on his plates figures which, so far as normal photography is concerned, ought not to have been there.” Dr. Wallace has given a great deal of thoughtful consideration to this subject, and has a large collection of genuine spirit photographs. In his book, _Miracles and Modern Spiritualism_,[14] he devotes sixteen pages specially to the topic. These pages—like everything else from Dr. Wallace’s pen—are worthy of careful study, the following sentences particularly so:— “It may be as well to clear away a popular misconception. Mr. G. H. Lewes advised the Dialectical Committee to distinguish carefully between ‘facts and inferences from facts.’ This is especially necessary in the case of what are called spirit photographs. The figures which occur in these, when not produced by any human agency, may be of ‘spiritual’ origin, without being figures ‘of spirits.’ There is much evidence to show that they are, in some cases, forms produced by invisible intelligences, but distinct from them. In other cases the intelligence appears to clothe itself with matter capable of being perceived by us; but even then it does not follow that the form produced is the actual image of the spiritual form. It may be but a reproduction of the former mortal form with its terrestrial accompaniments, _for purposes of recognition_. Most persons have heard of these ‘ghost pictures,’ and how easily they can be made to order by any photographer, and are therefore disposed to think they can be of no use as evidence. But a little consideration will show that the means by which sham ghosts can be manufactured being so well known to all photographers, it becomes easy to apply tests or arrange conditions so as to prevent imposition.