apparition which repeats itself to his fancy. "But there are grounds for
the suspicion" (says Dr. Hibbert, "Philosophy of Apparitions," p. 250),
"that when ideas of vision are vivified to the height of sensation, a
corresponding affection of the optic nerve accompanies the illusion."
Muller ("Physiology of the Senses," p. 1392, Baley's translation) states
the same opinion still more strongly; and Sir David Brewster, quoted by
Dr. Hibbert (p. 251) says: "In examining these mental impressions, I
have found that they follow the motions of the eyeball exactly like the
spectral impressions of luminous objects, and that they resemble them also
in their apparent immobility when the eye is displaced by an external
force. If this result (which I state with much diffidence, from having
only my own experience in its favour) shall be found generally true by
others, it will follow that the objects of mental contemplation may be
seen as distinctly as external objects, and will occupy the same local
position in the axis of vision, as if they had been formed by the agency
of light." Hence the impression of an image once conveyed to the senses,
no matter how, whether by actual or illusory vision, is liable to renewal,
"independently of any renewed application of the cause which had
originally excited it," and the image can be seen in that renewal "as
distinctly as external objects," for indeed "the revival of the fantastic
figure really does affect those points of the retina which had been
previously impressed."




CHAPTER XLVI.

Julius Faber and Amy Lloyd stayed in my house three day, I and in their
presence I felt a healthful sense of security and peace. Amy wished to