formity, and point out that which seems to me most
probable. This subject is certainly very worthy the attention of the
physician, as it is a case concerning which he may often be
consulted, and which it may be sometimes in his power to cure.

A person is said to squint, when the axes of both his eyes are not
directed to the same object.

This defect consists in the wrong direction of one of the eyes only.
I have never met with an instance in which both eyes had a wrong
direction, neither have I seen one accurately described by any
author.

The generality of writers on this subject have supposed this defect
to proceed from a disease of, or want of proper correspondence in,
the muscles of the eyes, which not acting in proper concert with one
another, as in persons free from this blemish, are not able to point
both eyes to the same object. But this, I think, is very seldom the
cause, for when the other eye is shut, the distorted eye can be moved
by the action of its muscles, in all possible directions, as freely
as that of any other person, which shows that it is not owing to a
defect in the muscles, neither is it owing to a want of
correspondence in the muscles of both eyes; for when both eyes are
open, and the undistorted eye is moved in any direction whatever, the
other always accompanies it, and is turned the same way at the same
instant of time.

I shall next take notice of the hypothesis of M. de la Hire, who
supposes, that in the generality of mankind, that part of the retina
which is seated in and about the axis of the eye, is of a more
delicate sense and perception than what the rest of the coat is
endowed with; and therefore we direct both axes to the same object,
chiefly in order to receive the picture on that part of the retina
which can best perceive it; but in persons who squint, he conceives
the most sensible part of the retina of one eye, not to be placed in
the axis, but at some distance from it: and that, therefore, this
more sensible part of the retina is turned towards the object, to
which the other eye is directed, and thus causes squinting. This
ingenious hypothesis has been followed by Dr. Boerhaave, and many
other eminent physicians. If it be true, then if the sound eye be
shut, and the distorted eye alone be used to look at an object, it
must still be as much distorted as before, for the same reason: but
the contrary is true in fact; for if you desire such a person to
close his other eye and