continually allude,
which has left an abiding mark on the vocabularies of every language,
and which supplies the material out of which dreams and the
well-known hallucinations of sick people are built.

To my astonishment, I found that the great majority of the men of
science to whom I first applied protested that mental imagery was
unknown to them, and they looked on me as fanciful and fantastic in
supposing that the words "mental imagery" really expressed what I
believed everybody supposed them to mean. They had no more notion of
its true nature than a colour-blind man, who has not discerned his
defect, has of the nature of colour. They had a mental deficiency of
which they were unaware, and naturally enough supposed that those
who affirmed they possessed it, were romancing. To illustrate their
mental attitude it will be sufficient to quote a few lines from the
letter of one of my correspondents, who writes:--

"These questions presuppose assent to some sort of a proposition
regarding the 'mind's eye,' and the 'images' which it sees.... This
points to some initial fallacy.... It is only by a figure of speech
that I can describe my recollection of a scene as a 'mental image'
which I can 'see' with my 'mind's eye.' ... I do not see it ... any
more than a man sees the thousand lines of Sophocles which under due
pressure he is ready to repeat. The memory possesses it, etc."

Much the same result followed inquiries made for me by a friend
among members of the French Institute.

On the other hand, when I spoke to persons whom I met in general
society, I found an entirely different disposition to prevail. Many
men and a yet larger number of women, and many boys and girls,
declared that they habitually saw mental imagery, and that it was
perfectly distinct to them and full of colour. The more I pressed
and cross-questioned them, professing myself to be incredulous, the
more obvious was the truth of their first assertions. They described
their imagery in minute detail, and they spoke in a tone of surprise
at my apparent hesitation in accepting what they said. I felt that I
myself should have spoken exactly as they did if I had been
describing a scene that lay before my eyes, in broad daylight, to a
blind man who persisted in doubting the reality of vision. Reassured
by this happier experience, I recommenced to inquire among
scientific men, and soon found scattered instances of what I sought,
though in by no means the same