Chapter VII., " On Certain more Disputable Phenomena of

Spiritualism," deals with examples of the direct voice and direct writing, materialization and spirit photography, all of which phenomena have been termed ectoplasms by Professor Ochorowicz of Warsaw. " By Ectoplasy," says Sir William, " is meant the power of forming outside the body of the medium a concentration of vital energy or vitalized matter which operates temporarily in the same way as the body from which it is drawn, so that visible, audible or tangible human-like phenomena are produced. This is very much like the ' psychic force ' hypothesis under a new name. The chapter " On the Canons of Evidence in Psychical Research " includes a sentence which might well be taken to heart by the too sceptical : "It is utterly unphilosophical to ridicule or deny well-attested phenomena because they are inexplicable." Sir William shows how the critical examination of psychic phenomena has languished because of the lack of trained scientific observers, those devoting themselves to the subject being for the most part persons of more enthusiasm than judg- ment. The chapter on theories is eminently useful. " I have never yet," says the author, " met with anyone who has seriously studied the evidence or engaged in prolonged investigation of this subject who holds ' that all mediums are impostors.' " The theories examined to account for supernormal phenomena include those of hallucination, which is only partially admitted as a cause. Exo-neural action of the brain which is, however, a sub-conscious action, an effect of the subliminal self, but perhaps the most interesting of the hypotheses which account for these miraculous happenings is described as follows : "It may be that the intelligence operating at a seance is a thought- projection of ourselves — that each one of us has his simu- lacrum in the unseen ; that with the growth of our life and character here a ghostly image of oneself is growing up in the invisible world." The Problem of Mediumship is the subject of the tenth chapter. Objection is taken to the word " medium," not only because of its associations, but for more scientific reasons. A separate division of the"