a composition of
fibres, that are so many imperceptible tubes or pipes interwoven on all
sides with invisible glands or strainers.

This general idea of a human body, without considering it in its niceties
of anatomy, lets us see how absolutely necessary labour 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 cleanse that infinitude of pipes and strainers of which it is
composed, and to give their solid parts a more firm and lasting tone.
Labour or exercise ferments the humours, casts them into their proper
channels, throws off redundancies, and helps nature in those secret
distributions, without which the body cannot subsist in its vigour, nor
the soul act with cheerfulness.

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[98], that we must ascribe
the spleen[99], which is so frequent in men of studious and sedentary
tempers, as well as the vapours[99] to which those of the other sex are
so often subject.

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
these compressions, extensions, contortions, dilatations, 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 honour, even food and
raiment are not to be come at without the toil of the hands and sweat of
the brows. Providence furnishes materials, but expects that we should
work them up ourselves. The earth must be laboured before it gives its
increase, and when it is forced into its several products, how many hands
must they pass through before they are fit for use? Manufactures, trade,
and agriculture, naturally employ more than nineteen parts of the species
in twenty; and as for those who are not obliged to lab