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 of the body,
as is proper for its welfare, it is so ordered, that nothing, valuable
can be procured without it. Not to mention riches and honor, even food
and raiment are not to be come at without the toil of the hands and
sweat of the brows.

6. Providence furnishes materials, but expects that we should work them
up ourselves. The earth must be labored before it gives its increase,