_The capillary vessels are glands._ 2. _Their excretory ducts.
Experiments on the mucus of the intestines, abdomen, cellular membrane,
and on the humours of the eye._ 3. _Scurf on the head, cough, catarrh,
diarrhoea, gonorrhoea._ 4. _Rheumatism. Gout. Leprosy._ II. 1. _The
most minute membranes are unorganized._ 2. _Larger membranes are
composed of the ducts of the capillaries, and the mouths of the
absorbents._ 3. _Mucilaginous fluid is secreted on their surfaces._
III. _Three kinds of rheumatism._

I. 1. The capillary-vessels are like all the other glands except the
absorbent system, inasmuch as they receive blood from the arteries,
separate a fluid from it, and return the remainder by the veins.

2. This series of glands is of the most extensive use, as their excretory
ducts open on the whole external skin forming its perspirative pores, and
on the internal surfaces of every cavity of the body. Their secretion on
the skin is termed insensible perspiration, which in health is in part
reabsorbed by the mouths of the lymphatics, and in part evaporated in the
air; the secretion on the membranes, which line the larger cavities of the
body, which have external openings, as the mouth and intestinal canal, is
termed mucus, but is not however coagulable by heat; and the secretion on
the membranes of those cavities of the body, which have no external
openings, is called lymph or water, as in the cavities of the cellular
membrane, and of the abdomen; this lymph however is coagulable by the heat
of boiling water. Some mucus nearly as viscid as the white of egg, which
was discharged by stool, did not coagulate, though I evaporated it to one
fourth of the quantity, nor did the aqueous and vitreous humours of a
sheep's eye coagulate by the like experiment: but the serosity from an
anasarcous leg, and that from the abdomen of a dropsical person, and the
crystalline humour of a sheep's eye, coagulated in the same heat.

3. When any of these capillary glands are stimulated into greater
irritative actions, than is natural, they secrete a more copious material;
and as the mouths of the absorbent system, which open in their vicinity,
are at the same time stimulated into greater action, the thinner and more
saline part of the secreted fluid is taken up again; and the remainder is
not only more copious but also more viscid than natural. This is more or
less troublesome or noxious according to the importance of t