14 
Mr. Home's Lecture 
which have been made upon persons who have a confirmed 
squint, which all agree in stating, that one of the eyes is too 
imperfect to see distinctly. 
From these observations, it would be natural to suppose that 
the loss of sight in one eye, should produce the appearance of 
squinting, which is by no means the case ; for when that hap- 
pens, the motions of the two eyes continue to correspond, al- 
though not exactly; but the deviation is not equal to that 
which is met with in squinting; it is nearer to that which 
occurs in double vision. 
The reason why the imperfect eye of a squinting person is 
directed from the object, while a blind one in its motions fol- 
lows the other, is, probably, that the indistinct vision of the 
imperfect eye prevents the muscles from directing it to the 
object with the same accuracy as those of the other do ; this 
small deviation from the axis of vision renders the object 
double, and interferes with the vision of the perfect eye ; and 
it is in the effort to get rid of the confused image that the 
muscles acquire a habit of neglecting to use the imperfect eye. 
It may also happen, when the eye is so imperfect as not 
to receive a correct image of any object, that it may have been 
neglected from the beginning. Distinct vision being at once 
obtained by the perfect eye, the end is answered, and the mind 
is never afterwards led to employ the other. 
The direction the eye takes under either of these circum- 
stances is inwards, towards the nose, the adductor muscle being 
stronger, shorter, and its course more in a straight line, than any 
of the other muscles of the eye. 
That the eye, when not accurately directed to the object, 
produces confused vision, and is for that reason turned away, 
