d today by artificial means. If a sensitive subject be
hypnotized (and there is some analogy to the hypnotic pass in the fact
that the fairy invariably waved her wand before the eyes of the
onlooker), hallucinations of various types may be induced. Thus, our
subject may be persuaded to see, for instance, a dog walking across the
carpet, whereas there is no dog there. He may be persuaded that there is
a stream in front of him flowing through the drawing-room, and that it
is necessary for him, in order to prevent his feet from becoming wet, to
take off his shoes and socks, and turn up his trousers. Hypnotic
suggestion will perform this, and it may be said that suggestion alone,
even when the subject is not in the hypnotic state, may be employed to
produce many of these hallucinatory pictures. On the contrary, it is
possible to suggest to our subject that such and such an object is
gradually diminishing in size, and finally that it disappears
altogether. He sees and describes this diminution, and finally looks in
vain for the object which, he asserts, has vanished, but which, as a
matter of fact, is perfectly visible to all others not under the
influence of the suggestion. We frequently suffer from these "negative
hallucinations," as they are called, in our ordinary daily life. We
cannot find an object which is perfectly visible--resting in the very
centre of the area over which we are searching diligently. Suddenly we
discover it; it seems incredible to us that we have not seen it before;
it seems to have sprung into being as though placed there by some
invisible hand. Nevertheless it had remained throughout in the one
position, and the only remarkable factor was our inability to see it.
Such cases are well known to psychologists (the power of suggestion in
inducing both positive and negative hallucinations), and this--both in
the normal and the hypnotic state--is well recognized.

Now it is only necessary for us to extend our conception somewhat in
order to see the scientific truths contained in many fairy stories, in
which one of the characters--hero, fairy, or what not--becomes visible
and invisible at will. It is only necessary for us to conceive that some
degree of mental influence had been brought to bear upon the minds of
the onlookers, and that suggestion had been skilfully employed, in order
to account for many of these stories. I know of a case in which the
operator made his subject, who remained practically in a