is, that an over-ready perception of sharp mental
pictures is antagonistic to the acquirement of habits of
highly-generalised and abstract thought, especially when the steps
of reasoning are carried on by words as symbols, and that if the
faculty of seeing the pictures was ever possessed by men who think
hard, it is very apt to be lost by disuse. The highest minds are
probably those in which it is not lost, but subordinated, and is
ready for use on suitable occasions. I am, however, bound to say,
that the missing faculty seems to be replaced so serviceably by other
modes of conception, chiefly, I believe, connected with the
incipient motor sense, not of the eyeballs only but of the muscles
generally, that men who declare themselves entirely deficient in the
power of seeing mental pictures can nevertheless give life-like
descriptions of what they have seen, and can otherwise express
themselves as if they were gifted with a vivid visual imagination.
They can also become painters of the rank of Royal Academicians.

The facts I am now about to relate are obtained from the returns of
100 adult men, of whom 19 are Fellows of the Royal Society, mostly
of very high repute, and at least twice, and I think I may say three
times, as many more are persons of distinction in various kinds of
intellectual work. As already remarked, these returns taken by
themselves do not profess to be of service in a general statistical
sense, but they are of much importance in showing how men of
exceptional accuracy express themselves when they are speaking of
mental imagery. They also testify to the variety of experiences to
be met with in a moderately large circle. I will begin by giving a
few cases of the highest, of the medium, and of the lowest order of
the faculty of visualising. The hundred returns were first
classified according to the order of the faculty, as judged to the
best of my ability from the whole of what was said in them, and of
what I knew from other sources of the writers; and the number
prefixed to each quotation shows its place in the class-list.

VIVIDNESS OF MENTAL IMAGERY.

(From returns, furnished by 100 men, at least half of whom are
distinguished in science or in other fields of intellectual work.)

_Cases where the faculty is very high_.

1. Brilliant, distinct, never blotchy.

2. Quite comparable to the real object. I feel as though I was
dazzled, _e.g._ when recalling the sun to my mental vision.

3. In so