the appetite keen from habit, yet every pupil should practise some
self-denial, and not eat as much as the appetite craves, the first
week of the session. After some days, the real wants of the system
will generally be manifested by a corresponding sensation of hunger.

_Observation._ It is a common observation that in academies and
colleges, the older students from the country, who have been
accustomed to hard manual labor, suffer more frequently from defective
digestion and impaired health than the younger and feebler students
from the larger towns and cities.

281. _Food is essential in maintaining a proper temperature of the
system._ The heat of the system, at least in part, is produced in the
minute vessels of the several organs, by the union of oxygen with
carbon and hydrogen, which the food and drink contain. The amount of
heat generated, is greatest when it is most rapidly removed from the
system, which occurs in cold weather. This is the cause of the system
requiring more food in winter than summer.

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279. Why should the quantity of food be diminished when the exercise
is lessened? What effect if this principle be disregarded? 280. To
what class is this remark applicable? What is often observed among
students in academies and colleges? 281. State another demand for
food. What is one source of heat in the body?

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_Observation._ Persons that do not have food sufficient for the
natural wants of the system, require more clothing than those who are
well fed.

282. The last-mentioned principle plainly indicates the propriety and
necessity of lessening the quantity of food as the warm season
approaches. Were this practised, the tone of the stomach and the vigor
of the system would continue unimpaired, the "season complaints" would
be avoided, and the "strengthening bitters" would not be sought to
create an appetite.

_Observation._ Stable-keepers and herdsmen are aware of the fact, that
as the warm season commences, then animals require less food. Instinct
teaches these animals more truly, in this particular, than man allows
reason to guide him.

283. _The quantity of food should have reference to the present
condition of the digestive organs._ If they are weakened or diseased,
so that but a small quantity of food can be properly digested or
changed, that amount only should be taken. Food does not invigorate
the system, except it is changed, as has been