38 MAMMALIA — MAN. 



expansion than any other parts of the two-fold growth. Though in vivipa^ 

 rous animals, and particularly in man, they are, at first, by no means so 

 large in proportion as in the oviparous classes, yet they obtain their due 

 formation sooner than any other parts of the body. Thus it is also with the 

 organ of hearing. The little bones that help to compose the internal parts 

 of the ear, are entirely formed, before any of the other bones have acquired 

 any part of their growth and solidity. Hence it is evident, that those parts 

 of the body which are furnished with the greatest quantity of nerves, are 

 those which appear the soonest, and which are the soonest brought to 

 perfection. 



Mr Cheselden having couched for a cataract a boy of thirteen years 

 of age, who had been blind from his birth, and having thus communicated 

 to him the sense of sight, was at great pains to mark the progress of his 

 visual powers. This youth, though hitherto incapable of seeing, was not, 

 however, absolutely and entirely blind. Like every other person whose 

 vision is obstructed by a cataract, he could distinguish day from night, and 

 even black from white, or either of them from the vivid color of scarlet. Of 

 the form of bodies, however, he saw nothing ; nor of colors themselves, 

 unless the light was strong. At first, the operation was performed only 

 upon one of his eyes ; and when he saw for the first time, so far was he 

 from forming the smallest conception of distances, that he supposed, (as he 

 himself expressed it,) that every thing he saw touched his eyes, in the same 

 manner as every thing he felt touched his skin. The objects that pleased 

 him most were those of which the surfaces were plane, and the figures 

 regular ; though as yet he could in no degree judge of their different forms, 

 or assign a reason why some were more agreeable to him than others. 

 The ideas he had entertained of colors during his former dark state, were so 

 imperfect, that when he saw them in reality, he could hardly be persuaded 

 they were the same. When such objects were shown him as he had been 

 formerly familiar with by the touch, he observed them with earnestness, in 

 order to distinguish them a second time. As of these, however, he had too 

 many to retain all at once, the greatest number were forgotten ; and for one 

 thing which he knew, after seeing it, there were a thousand things, accord- 

 ing to his own declaration, of which he no longer possessed the smallest 

 remembrance. He was very much surprised to find that those persons and 

 those things which he had loved best, were not the most pleasing to the 

 eye ; nor could he help testifying his disappointment in finding his parents 

 less handsome than he had conceived them to be. Before he could distin- 

 guish that a picture resembled a solid body, about two months elapsed. Till 

 then, he only considered it as a surface, diversified by a variety of colors: 

 but when he began to' perceive that these shadings actually represented 

 human beings, he also began to examine by the touch, whether they had 

 not the usual qualities of such bodies ; and great was his surprise to find 

 smooth and even, what he had supposed a very unequal surface. He was 



