When Peter was released from prison by the angel—and it is not amiss here to remark, that even he “wist not that it was true which was done by the angel, but thought he saw a vision,” that is, he did not believe his senses, but supposed himself the victim of a spectral illusion—but when he was released, and went and knocked at the door of the gate, where many of his friends were assembled, they, not conceiving it possible he could have escaped, said, when the girl who had opened the door insisted that he was there, “It is his angel.” What did they mean by this? The expression is not _an_ angel, but _his_ angel. Now, it is not a little remarkable, that in the East, to this day, a double, or doppelgänger, is called a man’s angel, or messenger. As we can not suppose that this term was used otherwise than seriously by the disciples that were gathered together in Mark’s house, for they were in trouble about Peter, and, when he arrived, were engaged in prayer, we are entitled to believe they alluded to some recognised phenomenon. They knew, either that the likeness of a man—his spiritual self—sometimes appeared where bodily he was not; and that this _imago_ or _idolon_ was capable of exerting a mechanical force, or else that other spirits sometimes assumed a mortal form, or they would not have supposed it to be Peter’s angel that had _knocked_ at the gate. Dr. Ennemoser, who always leans to the physical rather than the psychical explanation of a phenomenon, says, that the faculty of self-seeing, which is analogous to seeing another person’s double, is to be considered an illusion; but that this imago of another seen at a distance, at the moment of death, must be supposed to have an objective reality. But if we are capable of thus perceiving the imago of another person, I can not comprehend why we may not see our own; unless, indeed, the former was never perceived but when the body of the person seen was in a state of insensibility; but this does not always seem to be a necessary condition, as will appear by some examples I am about to detail. The faculty of perceiving the object, Dr. Ennemoser considers analogous to that of second sight, and thinks it may be evolved by local, as well as idiosyncratical conditions. The difficulty arising from the fact that some persons are in the habit of seeing the wraiths of their friends and relations, must be explained by his hypothesis. The spirit, as soon as liberated from the body, is adapted for communion with _all_ spirits, embodied or otherwise; but all embodied spirits are not prepared for communion with it.