ner or later they are
manifested in muscular weakness, dyspepsia, and nervous irritability.

_Observation._ The custom among farmers of enduring severe and undue
toil for several successive days, and then spending one or two days in
idleness to _rest_, is injudicious. It would be far better to do less
in a day, and continue the labor through the period devoted to
idleness, and then no rest will be demanded.

189. _Every part of the muscular system should have its appropriate
share of exercise._ Some employments call into exercise the muscles of
the upper limbs, as shoe-making; others, the muscles of the lower
limbs; while some, the muscles of both upper and lower limbs, with
those of the trunk, as farming. In some kinds of exercise, the lower
limbs are mainly used, as in walking; in others, the upper limbs; and
again, the muscles of the trunk, together with those of the upper and
lower limbs, as in archery, quoits, playing ball. Those trades and
kinds of exercise are most salutary, in which all the muscles have
their due proportion of action, as this tends to develop and
strengthen them equally. Thus labor upon the farm and domestic
employment are superior as vocations, and archery, quoits, and
dancing, if the air is pure, among the pastimes. For sedentary
persons, that kind of exercise is best which calls into action the
greatest number of muscles.

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188. How should exercise be taken? What is said respecting irregular
exercise? Are the consequences of neglected exercise immediately
apparent? What practical observation is given? 189. Should every
muscle have its due amount of exercise? Mention some employments that
only call into action the muscles of the upper limbs. Those of the
lower limbs, those of the trunk and limbs. Mention, in the different
pastimes, what muscles are called into action.

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190. _The proper time for labor or exercise should be observed._ This
is modified by many circumstances. As a general rule, the morning,
when the air is pure and the ground dry, is better than the evening;
for then, the powers of the body are greatest. Severe exercise and
labor should be avoided immediately before or after eating a full
meal, for the energies of the system are then required to perform the
digestive function. For similar reasons, it is not an appropriate time
for energetic muscular action immediately before or after severe
mental toil, as the powers o