Further, it is not absolutely true to say, that the metaphysical theories established upon the revelations of spirits are new. The life of some of the ‘saints’ in the Roman Church offers us several examples, one of the most celebrated being the devotion to the _Sacrè Cœur de Jésus_,’ a special kind of worship based upon revelations claimed to have been accorded to a nun named Marie Alacoque, who lived in the eighteenth century. Monastic life has not the monopoly of such experiences. Commerce with spirits appears to be likewise one of the elements of the religious ceremonies of the Shakers; even the Mormons seem to indulge in practices similar to those of spiritism; Jérôme Cardan, John Dee, Martinez de Pasqually pass for having held intercourse with immaterial beings; members of the order of the Red Cross have also been looked upon as holding frequent intercourse with diverse genii. If we study the history of human thought, we see that nothing is really new, nothing save perhaps the contemporary extension of spiritism. From many points of view, spiritism appears to play a rôle in the civilised, sceptical, material society of to-day, analogous to the simple rôle which Christianity played in the second and third centuries of our era. But this is a sociological problem; its examination, however interesting it may be, would lead me beyond the limits I have traced for myself. I will confine myself, therefore, to drawing from the brief historical account I have just given, the conclusion it admits of. The facts studied by Janet and others are anterior to spiritism, and cannot be legitimately designated by this name. I have already indicated that this word expresses an _ensemble_ of metaphysical and religious doctrines explaining psychical phenomena by the intervention of spirits, and drawing their teachings from the revelations attributed to these same spirits. It is terminologically incorrect to designate these facts by a word which has a wider signification, since it expresses an explanatory hypothesis of these same facts. Custom has consecrated the word ‘psychical’ facts or phenomena: this term is also imperfect, and it seems to me preferable to adopt the new term _Metapsychical_ which Richet recommends. Therefore, in the actual state of research, the scientific problem, it seems to me, is not whether spiritism be true or false, but whether metapsychical phenomena be real or imaginary. As Richet and Ochorowicz have said, every medium may defraud, and the analysis of fraud is one of the most complicated problems which the study of psychical phenomena presents. It is also one of the most interesting. The Cambridge[37] experiments with Eusapia Paladino put clearly before us the question of fraud and its signification. [37] See Appendix B. Before entering upon the psychological examination of fraud, it appears to me necessary to explain the signification of the terms I am going to use, and after that to classify medianic phenomena.