The only plausible theory which in any way accounts for the Piper and similar phenomena--short of the spiritistic--is one based upon the existence of independently fluctuating strata of the medium's mind, acquiring their knowledge by means of telepathy, clairvoyance, and other supernormal means. This view of the case is held and defended with extreme ingenuity and persuasiveness by Professor Flournoy in his _Spiritism and Psychology_--a book which I myself think should be read by every one interested in psychics or inclined to "dabble in spiritualism." The complete isolation and individuality of the various personalities involved could only be explained, it seems to me, by postulating a series of subliminal strata, between which there would be no memory connection--very much like Mr. Gurney's strata obtained by him and described in his paper on "The Stages of Hypnotic Memory" (_Proceedings_, vol. iv. pp. 515-31). In this way alone could we account for the facts; but even so, are they explained? When psychical research becomes a recognized science there will be ample room for "specialization," and for many years of study in each branch of the work. Consider, for instance, the many ramifications and possibilities which would be thrown open to the researcher! A man might become a "specialist" in haunted houses, in the investigation of such cases, and in their "treatment" and "cure." He would then have to investigate the nature and character of the phenomena which occur in them, and of the intelligences which manifest themselves. The nature of the figures seen in such houses would form a special branch of research, and the degree of their objectivity or subjectivity in any particular case. Numerous experiments might be tried, such as crystal-gazing, automatic writing, seances, induced dreams, etc. Experiments should be tried in photographing the apparitions, and in getting them to register their presence upon delicate and sensitive instruments of all sorts. Phonographic records of the "footsteps" of the ghost (if such occur) should be made, and a record taken of all the sounds and noises which occur in the house. Clairvoyants should be sent on "trips" to ascertain the character of the haunting, if possible, in order to "check off" their descriptions against the experiences of those living in the house. Communication should be established with the "haunting spirits," if possible, by means of raps, table-tipping, etc. The character of the phenomena should be studied, and the _physical_ separated from the _mental_. The nature of the intelligence "haunting" the house should be investigated psychologically. The dreams of those who sleep in the house should be recorded and analysed. Animals should be taken to live in the house, to see whether or not they perceive anything unusual. The effect of suggestion, exorcism, etc., should be tried and noted. Experiments in hypnotism, "magnetism," etc., should be conducted in the house. Red