ial in the eye, so as to cause pain, the violent and
frequent nictitation is caused by the faculty of sensation.

This disease is sometimes produced by the introversion of the edge of the
lower eyelid, which bends the points of the hairs of the eyelash upon the
ball of the eye, which perpetually stimulate it into painful sensation.
This introversion of the eyelid is generally owing to a tumor of the
cellular membrane below the edge of the eyelid, and though a very
troublesome complaint may often be cured by the following simple means. A
little common plaster spread on thin linen, about a quarter of an inch
long, must be rolled up so as to be about the size of a crow-quill, this
must be applied immediately below the eyelash on the outside of the eye;
and must be kept on by another plaster over it. This will then act as a
slight compression on the tumor under the eyelash, and will prevent the
hairs from touching the eye-ball. In a week or two the compression will
diminish the tumor it lies over, and cure this painful deformity.

9. _Oscitatio et pandiculatio._ Yawning and stretching of the limbs is
produced either by a long inactivity of the muscles now brought into
action, as sometimes happens after sleep, or after listening a long time to
a dull narrative; or it is produced by a too long continued action of the
antagonist muscles. In the former case there is an accumulation of
sensorial power during the quiescence of the muscles now brought into
action; which probably constitutes the pain or wearisomeness of a continued
attitude. In the latter case there is an exhaustion of sensorial power in
the muscles, which have lately been acting violently, and a consequent
accumulation in the muscles, which are antagonists to them, and which were
at rest.

These involuntary motions are often seen in paralytic limbs, which are at
the same time completely disobedient to the will; and are frequently
observable in very young children; and from thence we may conclude, that
these motions are learnt before nativity; as puppies are seen to open their
mouths before the membranes are broken. See Sect. XVI. 2.

Where these motions are observed in limbs otherwise paralytic, it is an
indication that electric shocks may be employed with advantage, as the
excitability of the limb by irritation is not extinct, though it be
disobedient both to volition and sensation.

10. _Tenesmus_ consists in violent and frequent ineffectual efforts to
disch