muscles thus employed.

5. If the muscles of any limb are inflamed, they do not move without pain;
so when the retina is inflamed, its motions also are painful. Hence light
is as intolerable in this kind of ophthalmia, as pressure is to the finger
in the paronychia. In this disease the patients frequently dream of having
their eyes painfully dazzled; hence the idea of strong light is painful as
well as the reality. The first of these facts evinces that our perceptions
are motions of the organs of sense; and the latter, that our imaginations
are also motions of the same organs.

6. The organs of sense, like the moving muscles, are liable to become
benumbed, or less sensible, from compression. Thus, if any person on a
light day looks on a white wall, he may perceive the ramifications of the
optic artery, at every pulsation of it, represented by darker branches on
the white wall; which is evidently owing to its compressing the retina
during the diastole of the artery. Savage Nosolog.

7. The organs of sense and the moving muscles are alike liable to be
affected with palsy, as in the gutta serena, and in some cases of deafness;
and one side of the face has sometimes lost its power of sensation, but
retained its power of motion; other parts of the body have lost their
motions but retained their sensation, as in the common hemiplagia; and in
other instances both these powers have perished together.

8. In some convulsive diseases a delirium or insanity supervenes, and the
convulsions cease; and conversely the convulsions shall supervene, and the
delirium cease. Of this I have been a witness many times in a day in the
paroxysms of violent epilepsies; which evinces that one kind of delirium is
a convulsion of the organs of sense, and that our ideas are the motions of