ontents in a little time.

I then passed a ligature round several branches of lacteals, and irritated
them much with a knife beneath the ligature, but could not make them
regurgitate their contained fluid into the bowels.

I am not indeed certain, that the nerve was not at the same time included
in the ligature, and thus the lymphatic rendered unirritable or lifeless;
but this however is certain, that it is not any quantity of any stimulus,
which induces the vessels of animal bodies to revert their motions; but a
certain quantity of a certain stimulus, as appears from wounds in the
stomach, which do not produce vomiting; and wounds of the intestines, which
do not produce the cholera morbus.

At Nottingham, a few years ago, two shoemakers quarrelled, and one of them
with a knife, which they use in their occupation, stabbed his companion
about the region of the stomach. On opening the abdomen of the wounded man
after his death the food and medicines he had taken were in part found in
the cavity of the belly, on the outside of the bowels; and there was a
wound about half an inch long at the bottom of the stomach; which I suppose
was distended with liquor and food at the time of the accident; and thence
was more liable to be injured at its bottom: but during the whole time he
lived, which was about ten days, he had no efforts to vomit, nor ever even
complained of being sick at the stomach! Other cases similar to this are
mentioned in the philosophical transactions.

Thus, if you vellicate the throat with a feather, nausea is produced; if
you wound it with a penknife, pain is induced, but not sickness. So if the
soles of the feet of children or their armpits are tickled, convulsive
laughter is excited, which ceases the moment the hand is applied, so as to
rub them more forcibly.

The experiment therefore above related upon the lacteals of a dead pig,
which were included in a strict ligature, proves nothing; as it is not the
quantity, but the kind of stimulus, which excites the lymphatic vessels
into retrograde motion.

XI. _The Causes which induce the retrograde Motions of animal Vessels; and
the Medicines by which the natural Motions are restored._

1. Such is the construction of animal bodies, that all their parts, which
are subjected to less stimuli than nature designed, perform their functions
with less accuracy: thus, when too watery or too acescent food is taken
into the stomach, indigestion, and flatulency, and