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 be-
