hat we are to believe that he does not perceive with the usual organs.
Upon the rule which the author adopts, that "the invisible is the only
true," we cannot rely upon our deceptive organs and should disbelieve
mesmerism _because_ we see it.

To analyse, in detail, the hypotheses of Mr Townshend would be quite
impossible in our limited space. We might, indeed, adopt method
sometimes used in controversial writing, and string together a parallel
column of minor contradictions. This would however, not only be totally
devoid of interest to the reader, but is not the object we have in view.
We seek not for critical errors or inconsistencies, but merely to
examine if there be any broad lines of truth or probability in his
theory. It is summed up as follows:--

"The real nature of vision is as shut to the vulgar as the mesmeric
mode of sight is to the learned.

"By the eye we appreciate light and colour only: the rest is an
operation of the judgment.

"Viewed metaphysically, seeing is but a particular kind of
knowledge: viewed physically, seeing consists in certain nervous
motions, responsive to the motions of a medium. That medium, in our
ordinary condition, is light, the action of which seems cut off and
intercepted in the case of mesmeric vision.

"When, therefore, we hear that a mesmerised person has correctly
seen an object through obstacles which to us appear opaque, we,
conceiving no means of communication between the person and the
object, exclaim that the laws of nature have been violated. But, in
all cases where information is conveyed through interrupted spaces,
show but the means of communication, and astonishment ceases.

"When we know that there is a medium permeating, in one or other of
its forms, all substances whatever, and that this medium is
eminently capable of exciting sensations of sight; and when we take
this in conjunction with a heightened sensibility in the
percipient person, rendering him aware of impulses whereof we are
not cognisant, we are no longer inclined to deny a fact or suppose
a miracle.

"Finally, all sensation has but one principle. All that is required
for its production is, that objects should be brought into a
certain relation with us by something intermediate; and this is
effected by the impulsions of certain media upon nerves, the last
change