100 ANIMAL MECHANISM. 



absorbed, with that deposited in the bones, to sustain the 

 system, which accounts for the sinking in of the eye : aa 

 the person recovers, the stomach resumes the task of 

 taking care of the body, the fat is deposited again, and 

 the eye becomes prominent as before. 



GLOBE OF THE EYE. 



When detached from the surrounding parts, the eye- 

 ball does not appear exactly round : it is, in outline, more 

 than two thirds of a large sphere, with a portion of a 

 lesser glebe laid upon it. 



The use of this arrangement is obvious. If the ball 

 had been actually round, the compass of vision would 

 have been very limited : as it is, the smaller portion, by 

 its short curve, protrudes so far beyond the socket, where 

 the globe is lodged for safely, that the sphere of vision is 

 very much enlarged. 



MUSCLES OF THE EYE. 



To move the ball, cords, called muscles, were neces- 

 sary ; otherwise, animals would have been obliged to turn 

 their bodies as often as an object was to be seen. Of 

 these, four are straight, going from the sides of the ball, 

 to be fastened jiear the hole, at the termination of the 

 bony cavity : their office is to hold the eye firmly, in a 

 fixed position, as in steadily contemplating a painting. 

 Two others are given, making six in the whole, to ex- 

 press, principally, the passions of the mind : they are 

 denominated the oblique, in consequence of their oblique 

 movement of the eye. One rolls it downward and out- 

 ward, as in viewing the shoulder ; the other, going through 

 a loop, which is so purely mechanical, that it has been 

 the theme of admiration with philosophers in all ages, 

 carries it upward and inward. The last action can be 

 shown by looking at a button, held on a line with the 

 nose, midway of the forehead. Although these oblique 

 muscles exist in monkeys and nearly all tribes of quadru- 

 peds, they are imperfectly developed ; showing most 

 conclusively that they were designed for expressing the 

 feelings and passions of man an ineffable language, 



