PHYSIOLOGY OF VISION. 171 



the eye the cause of this imperfection is avoided, and 

 this too, without the least inconvenience to ourselves, 

 since no'one in health, has ever yet complained of the 

 slightest difficulty in making the highest parts of objects 

 appear at the greatest distance from the surface of the 

 earth, whether he knew that he saw them in another 

 position or not. 



Now we have every reason to believe that our Crea- 

 tor, all things considered, has constructed us on the wis- 

 est and best plan, and therefore that he chose so to en- 

 dow us, whether by a peculiar faculty or not, as to see 

 things as they exist, though they are inverted in the eye, 

 rather than to correct this inversion by an additional 

 lens. This seerns to be the only explanation which it is 

 necessary to give this subject, for although physiologists 

 have puzzled themselves to show how it is, that we see 

 objects as we do, when all agree that the structure of 

 the eye inverts them ; still we can discern no more dif- 

 ficulty in this phenomenon, that we do in the fact, that an 

 engraver reverses all his lines, and that a printer reads 

 his type with the same facility that he does a printed 

 page ; both being matters of habit and experience. 



Minuteness of the image on the Retina. It would be 

 a curious, and not uninstructive subject, as displaying in 

 a very striking manner, the Wisdom and Power of God, 

 in the mechanism of his creatures, to estimate the dimen- 

 sions of the images of different objects, at various dis- 

 tances, on the retina, if indeed this could be done with 

 any accuracy. 



The expansion of the optic nerve which forms the 

 seat of vision, is only about half an inch in diameter, 

 and yet, on this space is painted with the most perfect 

 accuracy the image of every object which the eye be- 

 holds. Now the eye in an elevated situation may look 

 on the whole of a landscape to the distance of fifty miles; 

 and without perceptibly moving the visual organs, in- 

 clude a lateral view of probably twenty-five miles ; 

 and yet the whole of this extent, must be pictured on 



How might the inversion of the picture on the retina have been cor- 

 rected ? W hy do we see things perpendicularly 1 



