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Visionaries
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objects actually seen. There is also a hybrid case which depends on
fanciful visions fancifully perceived. The problems we have to consider
are, on the one hand, those connected with “induced” vision, and, on the
other hand, those connected with the interpretation of vision, whether the
vision be direct or induced.
It is probable that much of what passes for hallucination proper
belongs in reality to the hybrid case, being an illusive interpretation of
some induced visual cloud or blur. I spoke of the ever-varying patterns in
the optical field; these, under some slight functional change, may become
more consciously present, and be interpreted into fantasmal appearances.
Many cases could be adduced to support this view.
I will begin with illusions. What is the process by which they are
established? There is no simpler way of understanding it than by trying, as
children often do, to see “faces in the fire,” and to carefully watch the way
in which they are first caught. Let us call to mind at the same time the
experience of past illnesses, when the listless gaze wandered over the
patterns on the wall-paper and the shadows of the bed-curtains, and
slowly evoked the appearances of faces and figures that were not easily
laid again. The process of making the faces is so rapid in health that it is
difficult to analyse it without the recollection of what took place more
slowly when we were weakened by illness. The first essential element in
their construction is, I believe, the smallness of the area covered by the
glance at any instant, so that the eye has to travel over a long track before
it has visited every part of the object towards which the attention is
directed generally. It is as with a plough, that must travel many miles
before the whole of a small field can be tilled, but with this important
difference—the plough travels methodically up and down in parallel
furrows; the eye wanders in devious curves, with abrupt bends, and the
direction of its course at any instant depends on four causes: (1) on the
easiest sequence of muscular motion, speaking in a general sense, (2) on
idiosyncrasy, (3) on the mood, and (4) on the associations current at the
moment. The effect of idiosyncrasy is excellently illustrated by the
“Number-Forms,” where we observe that a very special sharply-defined
track of mental vision is preferred by each
