Apparition
according to a brief held by some, a disembodied spirit manifesting itself to mortal sight; according to the common theory an illusion involuntarily generated, by means of which figures or forms, not present to the actual sense, are nevertheless depictured with a vividness and intensity sufficient to create a temporary belief of their reality.
Such illusions are now generally held to result from an overexcited brain, a strong imagination, or some bodily malady. This theory explains satisfactorily a large majority of the stories of apparitions. Belief in spirits, visible and invisible, still persists, and an increase in the followers of spiritualism has been noted since the European War of 1914-