body, and the instinctive closing of one eyelid, in order that he may
see objects single, is an effort of his weakened judgment to set things
right once more.
While on this subject we may mention the experiment made by the famous
English surgeon Cheselden upon a boy who was born blind, and upon whom
he operated successfully.
This boy, who was thirteen years old at the time that Cheselden restored
to him the sense of sight, was not born absolutely blind, his affliction
having been caused by a cataract or film spread over the eyeball, which
allowed him to distinguish night from day, or black from white or
scarlet when placed in a very good light, although he was unable to
perceive the form of things around him. At first Cheselden operated on a
single eye, perfectly restoring its power; but so little idea of
distance did the new sense convey to the boy’s mind that for a long time
he imagined that everything touched his eyeball, just as those he felt
touched his skin, and it was only by the sense of touch that he could
persuade himself of the fallacy of his supposition. At first he had no
perception of form whatever, and could only recognize objects he had
already been familiar with after he had felt them all over. He was a
long time, for instance, before he could distinguish between the dog and
the cat without touching them, and was greatly surprised to find that
the persons and things he had liked best when blind were not always the
pleasantest to his newly acquired sense. His ideas of size, too, were
all at fault, and he could not, for a long time, be made to understand
how his father’s picture could be got into the back of his mother’s
watch; even after he had possessed his sight for a comparatively long
time, he could still only recognise people he had known during his
blindness by touching their faces. Whenever he saw a new object he
looked at it attentively for some time, in order, as it were, to learn
its form by heart; but his memory was at first so overtaxed that he
continually forgot his visual impressions, and mistook one thing for
another. He was more than two months before he could appreciate form as
depicted in a painting or drawing, having hitherto learned to consider
pictures as flat objects. When, however, he began to understand the
power of light and shade in producing the representations of solid
objects, he was often extremely surprised to find the surface on which
they were depicted quite flat when he touched it. The same thing
frequently happens to ourselves, when looking at the photographs of
bas-reliefs for instance. If these objects be well photographed, with
the proper arrangement of light and shade, the illusion is so complete
that the finger involuntarily touches the paper to feel if the surface
is not really raised. In the Bourse at Paris there are some figures
painted to represent bas-reliefs in so wonderful a manner, that
numberless bets have been made, lost and won, over them. When feeling
Public-domain text, read in full here on John Shaqi.
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