Mr. Bell on the motions of the eye, &c. 181 
the line. A much greater authority says we puzzle ourselves 
without necessity. “ We call that the lower end of an object 
which is next the ground.” No one can doubt that the ob- 
scurity here, is because the author has not given himself room 
to illustrate the subject by his known ingenuity and profound- 
ness. But it appears to me, that the utmost ingenuity will be 
at a loss to devise an explanation of that power by which the 
eye becomes acquainted with the position and relation of ob- 
jects, if the sense of muscular activity be excluded, which 
accompanies the motion of the eye-ball. 
Let us consider how minute and delicate the sense of mus- 
cular motion is by which we balance the body, and by which 
we judge of the position of the limbs, whether during activity 
or rest. Let us consider how imperfect the sense of touch 
would be, and how little of what is actually known through 
the double office of muscles and nerves, would be attained by 
the nerve of touch alone, and we shall be prepared to give 
more importance to the recti muscles of the eye, in aid of the 
sense of vision : to the offices performed by the frame around 
the eye-ball in aid of the instrument itself. 
Of the expression of the eye , and of the actions of the oblique 
muscles in disease. 
If, as I have alleged, the uses of the oblique muscles of the 
eye have been misunderstood, and if, as I hope presently to 
prove, the distinctions of the nerves have been neglected, the 
symptoms of disease, and the sources of expression in the 
eye, must remain to be explained. 
During sleep, in oppression of the brain, in faintness, in 
debility after fever, in hydrocephalus, and on the approach of 
death, the pupils of the eyes are elevated. If we open the 
