rses, sheep, and cows.

The next most frequent or most powerful efforts, which infants are first
tempted to produce, are those with the muscles in biting hard substances;
indeed the exertion of these muscles is very powerful in common
mastication, as appears from the pain we receive, if a bit of bone is
unexpectedly found amongst our softer food; and further appears from their
acting to so great mechanical disadvantage, particularly when we bite with
the incisores, or canine teeth; which are first formed, and thence are
first used to violent exertion.

Hence when a person is in great pain, the cause of which he cannot remove,
he sets his teeth firmly together, or bites some substance between them
with great vehemence, as another mode of violent exertion to produce a
temporary relief. Thus we have a proverb where no help can be had in pain,
"to grin and abide;" and the tortures of hell are said to be attended with
"gnashing of teeth."

Hence in violent spasmodic pains I have seen people bite not only their
tongues, but their arms or fingers, or those of the attendants, or any
object which was near them; and also strike, pinch, or tear, others or
themselves, particularly the part of their own body, which is painful at
the time. Soldiers, who die of painful wounds in battle, are said in Homer
to bite the ground. Thus also in the bellon, or colica saturnina, the
patients are said to bite their own flesh, and dogs in this disease to bite
up the ground they lie upon. It is probable that the great endeavours to
bite in mad dogs, and the violence of other mad animals, is owing to the
same cause.

4. If the efforts of our voluntary motions are exerted with still greater
energy for the relief of some disagreeable sensation, convulsions are
produced; as the various kinds of epilepsy, and in some hysteric paroxysms.
In all these diseases a pain, or disagreeable sensation is produced,
frequently by worms, or acidity in the bowels, or by a diseased nerve in
the side, or head, or by the pain of a diseased liver.

In some constitutions a more intolerable degree of pain is produced in some
part at a distance from the cause by sensitive association, as before
explained; these pains in such constitutions arise to so great a degree,
that I verily believe no artificial tortures could equal some, which I have
witnessed; and am confident life would not have long been preserved, unless
they had been soon diminished or removed by the univer