that of exercise, but
differs only from ordinary labor as it rises from another motive.

A country life abounds in both these kinds of labor, and for that reason
gives a man a greater stock of health, and consequently a more perfect
enjoyment of himself, than any other way of life.

2. I consider the body as a system of tubes and glands, or, to use a
more rustic phrase, a bundle of pipes and strainers, fitted to one
another after so wonderful a manner, as to make a proper engine for the
soul to work with. This description does not only comprehend the bowels,
bones, tendons, veins, nerves and arteries, but every muscle and every
ligature, which is a composition of fibres, that are so many
imperceptible tubes or pipes interwoven on all sides with invisible
glands or strainers.

3. This general idea of a human body, without considering it in its
niceties of anatomy, let us see how absolutely necessary labor is for
the right preservation of it. There must be frequent motions and
agitations, to mix, digest, and separate the juices contained in it, as
well as to clear and disperse the infinitude of pipes and strainers of
which it is composed, and to give their solid parts a more firm and
lasting tone. Labor or exercise ferments the humors, casts them into
their proper channels, throws off redundancies, and helps nature in
those secret distributions, without which the body cannot subsist in its
vigor, nor the soul act with cheerfulness.

4. I might here mention the effects which this has upon all the
faculties of the mind, by keeping the understanding clear, the
imagination untroubled, and refining those spirits that are necessary
for the proper exertion of our intellectual faculties, during the
present laws of union between soul and body. It is to a neglect in this
particular that we must ascribe the spleen, which is so frequent in men
of studious and sedentary tempers, as well as the vapours to which those
of the other sex are so often subject.

5. Had not exercise been absolutely necessary for our well-being, nature
would not have made the body so proper for it, by giving such an
activity to the limbs, and such a pliancy to every part, as necessarily
produce those compressions, extensions, contortions, dilations, and all
other kinds of motions that are necessary for the preservation of such a
system of tubes and glands as has been before mentioned. And that we
might not want inducements to engage us in such an exercise