168. A distinction must be made between incidental and spontaneous apparitions, and the faculty proper of seeing spirits. The former are frequent, particu- larly at the moment of the death of persons loved or known, and who come to warn us they are no longer in the world. There are numerous examples of facts of this kind, without reckoning visions during sleep. At other times, relatives or friends, who, though a longer or shorter time dead, appear either to warn us of a danger, or to.give advice, or to ask a service. The service a spirit can claim consists usually in the accomplishment of a thing he could not do while living, or in the help of prayers. These apparitions are isolated facts, which have always an individual and personal character, and do not constitute a faculty proper. The faculty consists in the possibility, if not permanent, at least very frequent, of seeing any spirit, even that of an entire stranger. It is this faculty that, properly speaking, constitutes seeing mediums.
Among seeing mediums there are those who see only those whom they call, and whom they describe with a perfect minuteness; they tell, to the smallest detail, their gestures, their expression of countenance, their features, costume, and even the sentiments by which they are animated. With others this faculty is still more general; they see all the surrounding spirit population go, come, and, as one might say, attend to their affairs.