is produced in a particular organ, that organ does not vibrate with the impression made upon it, but communicates it to another part on which a similar impression was formerly made.
Nicolai states that he made his illusion a source of philosophical amusement.
The spectres which haunted him came in the day time as well as the night, and frequently when he was surrounded by his friends; the ideal images mingling with the real ones, and visible only to himself.
Bernard Barton, the celebrated Quaker poet, describes an illusion of this nature in a manner peculiarly striking:— I only knew thee as thou wert, A being not of earth! I marvelled much they could not see Thou comest from above: And often to myself I said, How can they thus approach the dead?
But though all these, with fondness warm, Said welcome o'er and o'er, Still that expressive shade or form Was silent, as before! And yet its stillness never brought To them one hesitating thought.
I recollected that the mode of ex