parts of the system, rather than stimuli to excite it into action.

H. _The Origin of Associations._

Some trains or circles of associate motions must have been formed before
our nativity, as those of the heart, arteries, and capillaries; others have
been associated, as occasion required them, as the muscles of the diaphragm
and abdomen in vomiting; and others by perpetual habit, as those of the
stomach with the heart and arteries directly, as in weak pulse during
sickness; with the capillaries directly, as in the flushed skin after
dinner; and lastly, with the cellular absorbents reversely, as in the
increased absorption in anasarca during sickness; and with the irritative
motions of the organs of sense reversely, as in vertigo, or sea-sickness.
Some of these associations shall be here shortly described to facilitate
the investigation of others.

First, other congeries of glands occupy but a particular part of the
system, or constitute a particular organ, as the liver, or kidneys; but
those glands, which secrete the mucus, and perspirable matter, which are
called capillaries, are of very great extent; they receive the blood from
the arteries, separate from it the mucus, which lines every cell, and
covers every cavity of body; and the perspirable matter, which softens and
lubricates the whole surface of the skin, and the more extensive surface of
the air-vessels, which compose the lungs. These are supplied with blood by
the perpetual action of the heart and arteries, and have therefore their
motions associated with the former, and with each other, by sympathy, which
is sometimes direct, and sometimes reverse.

One branch of this association, the capillaries of the skin, are very
irritable by the increased quantities of cold and heat, another branch,
that of the lungs, has not the perception of cold and heat, but is liable
by direct sympathy to act in concert with the former, as in going into the
cold bath. And it is probable the capillaries of the internal membranes are
likewise directly affected by their sympathy with those of the skin, as
appears from the defect of secretion in ulcers during the cold fits of
agues.

The motions of this extensive system of capillaries, thus associated by
direct sympathy, are also associated with those of the heart and arteries,
sometimes by reverse and sometimes by direct sympathy; and thus constitute
simple fever. The cold paroxysm of which consists in their torpor, and the
hot o