lvanic disk is employed. The phenomena are physiological and not
electrical.

Our conviction is, that the results proceed entirely from _imagination
acting with a peculiar condition of the brain_, and that this
peculiarly passive and impressible condition of the brain is induced
by the _fixed gaze_ upon the disk. These are the only agencies which
we believe to be necessary, in order to give us an explanation of the
phenomena in question. In saying so, however, we are aware that such
data will seem to some inquirers insufficient to account for the
effects we have described. It may be said: 'We know that imagination
sometimes produces singular results, but can hardly see how it
explains the facts stated.' We have only to request that such
inquirers, before they throw aside our explanation, will give
attention to a few remarks on the power of imagination in certain
conditions. We propose, _1st_, To give some suggestions on this point;
_2d_, To notice the relations of imagination with reason; and, _3d_,
To inquire how far the physical means employed--the fixed gaze on the
disk--may be sufficient to affect the mental organ, the brain, so as
to alter its normal condition.

1. Our usual mode of speaking of imagination, is to treat it as the
opposite of all reality. When we say, 'that was merely an
imagination,' we dismiss the topic as not worthy of another thought.
For all ordinary purposes, this mode of speaking is correct enough;
but let us ask, Why is imagination so weak?--why are its suggestions
so evanescent? Simply because it is under the control of reason. But
if the action of reason could be suspended, we should then see how
great, and even formidable, is the imaginative power. It is the most
untiring of all our mental faculties, refusing to be put to rest even
during sleep: it can alter the influence of all external agents--for
example, can either assist or prevent the effects of medicine--can
make the world a prison-house to one man, and a paradise to
another--can turn dwarfs into giants, and make various other
metamorphoses more wonderful than any described by Ovid; nay, these
are all insufficient examples of its power when left without control;
for it can produce either health, or disease, or death!

To give a familiar instance of the control under which it is generally
compelled to act: You are walking home in the night-time, and some
withered and broken old tree assumes, for a moment, the appearance of
a gian