AXIMALS. 



eye, by trying for some: time, we shall find, 

 that while we distinctly behold the black 

 spots that are to the ri>j;!jt and left, that which 

 is in the middle remains totally unseen. Or, 

 in other words, when we bring that part of the 

 eye, where the optic artery runs, to fall upon 

 the object, it will then become invisible. 

 This defect, however, in either eye, is always 

 corrected by both, since the part of the object 

 that is unseen by one, will be very distinctly 

 perorivrd by the other.'' 



Beside the former defects, we can have no 

 idea of distances from the sight, without the 

 help of touch. Naturally every object we 

 see appears to be within our eyes ; and a 

 child, who has as yet made but little use of 

 the sense of feeling, must suppose that every 

 thing it sees makes a part of itself. Such ob- 

 jects are only seen more or less bulky as they 

 approach, or recede from its eyes ; so that 

 a lly that is near will appear larger than an 

 ox at a distance. It is experience alone that 

 can rectify this mistake ; and a long acquain- 

 tance with the real size of every object, quick- 

 ly assures us of the distance at which it is seen. 

 The last man in a file of soldiers appears in 

 reality much less, perhaps ten times more di- 

 minutive, than the man next to us ; however, 

 we do not perceive this difference, but con- 

 tinue to think him of equal stature ; for the 

 numbers we have seen thus lessened by dis- 

 tance, and have found, by repeated experi- 

 ence, to be of the natural size when we come 

 closer, instantly correct the sense, and every 

 object is perceived with nearly its natural 

 proportion. But it is otherwise, if we observe 

 objects in such situations as we have not had 

 sufficient experience to correct the errors of 

 the eye ; if, for instance, we look at men from 

 the top of a high steeple, they, in that case, 

 appear very much diminished, as we have not 

 had a habit of correctitig the sense in that po- 

 sition. 



Although a small degree of reflection will 

 serve to convince us of the truth of these po- 

 sitions, it may not be amiss to strengthen 

 them by an authority which cannot be dispu- 

 ted. Mr. Cheselden having couched a boy 

 of thirteen for a cataract, who had hitherto 

 been blind, and thus at once having restored 

 him to sight, curiously marked the progress 

 of his mind upon that occasion. This youth, 



though he had been till then incapable of see- 

 ing, yet was not totally blind, but could tell 

 day from night, as persons in his situation 

 always may. He could also, with a strong 

 light, distinguish black from white, and either 

 from the vivid colour of scarlet : however, he 

 saw nothing of the form of bodies ; and, with- 

 out a bright light, not even colours themselves. 

 He was, at first, couched only in one of his 

 eyes; and when he saw for the first time, he 

 was so far from judging of distances, that he 

 supposed his eye touched every object tiia- 

 he saw, in the same manner as his hands 

 might be said to feel them. The objects that 

 were most agreeable to him were such as were 

 of plain surfaces and regular figures : though 

 he could as yet make no judgment whatever 

 of their different forms, nor give a reason why 

 one pleased him more than another. Al- 

 though he could form some idea of colours 

 during his state of blindness, yet that was not 

 sufficient to direct him at present; and he 

 could scarcely be persuaded that the colours 

 he now saw were the same with those he had 

 formerly conceived such erroneous ideas of. 

 He delighted most in green ; but black ob- 

 jects, as if giving him an idea of his former 

 blindness, he regarded with horror. He had, 

 as was said, no idea of forms ; and was una- 

 ble to distinguish one object from another, 

 though never so different. When those things 

 were shown him, which he had been former- 

 ly familiarized to by his feeling, he beheld 

 them with earnestness, in order to remember 

 them a second time : but as he had too many 

 to recollect at once, he forgot the greatest 

 number ; and for one he could tell, after see- 

 ing, there was a thousand he was totally un- 

 acquainted with. He was very much sur- 

 prised to find, that those things and persons 

 he loved best, were not the most beautiful to 

 be seen; and even testified displeasure in 

 not finding his parents so handsome as he 

 conceived them to be. It was near two months 

 before he could find that a picture resembled 

 a solid body. Till then he only considered 

 it as a flat surface, variously shadowed ; but 

 when he began to perceive that these kind 

 of shadings actually represented human beings, 

 he then began to examine, by his touch, whe- 

 ther they had not the usual qualities of such 

 bodies, and was .oreatly surprised to find, what 



