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I.--1. The nervous system has its origin from the brain, and is distributed
to every part of the body. Those nerves, which serve the senses,
principally arise from that part of the brain, which is lodged in the head;
and those, which serve the purposes of muscular motion, principally arise
from that part of the brain, which is lodged in the neck and back, and
which is erroneously called the spinal marrow. The ultimate fibrils of
these nerves terminate in the immediate organs of sense and muscular
fibres, and if a ligature be put on any part of their passage from the head
or spine, all motion and perception cease in the parts beneath the
ligature.

2. The longitudinal muscular fibres compose the locomotive muscles, whose
contractions move the bones of the limbs and trunk, to which their
extremities are attached. The annular or spiral muscular fibres compose the
vascular muscles, which constitute the intestinal canal, the arteries,
veins, glands, and absorbent vessels.

3. The immediate organs of sense, as the retina of the eye, probably
consist of moving fibrils, with a power of contraction similar to that of
the larger muscles above described.

4. The cellular membrane consists of cells, which resemble those of a
sponge, communicating with each other, and connecting together all the
other parts of the body.

5. The arterial system consists of the aortal and the pulmonary artery,
which are attended through their whole course with their correspondent