s vital principle, and withdrawing the more
deleterious element. But, when the light is withdrawn, this process is
reversed, and all vegetables exhale carbonic acid, and inspire the
oxygen of the air. Thus it appears, that the atmosphere of day is much
more healthful than that of the night, especially out of doors.

Moreover, when the body is fatigued, it is much more liable to
deleterious influences, from noxious particles in the atmosphere, which
may be absorbed by the skin or the lungs. In consequence of this, the
last hours of daily labor are more likely to be those of risk,
especially to delicate constitutions. This is a proper reason for
retiring to the house and to slumber, at an early hour, that the body
may not be exposed to the most risk, when, after the exertions of the
day, it is least able to bear it.

The observations of medical men, whose inquiries have been directed to
this point, have decided, that from six to eight hours, is the amount of
sleep demanded by persons in health. Some constitutions require as much
as eight, and others no more than six, hours of repose. But eight hours
is the maximum for all persons in ordinary health, with ordinary
occupations. In cases of extra physical exertions, or the debility of
disease, or a decayed constitution, more than this is required. Let
eight hours, then, be regarded as the ordinary period required for
sleep, by an industrious people, like the Americans. According to this,
the practice of rising between four and five, and retiring between nine
and ten, in Summer, would secure most of the sunlight, and expose us the
least to that period of the atmosphere, when it is most noxious. In
Winter, the night air is less deleterious, because the frost binds
noxious exhalations, and vegetation ceases its inspiring and expiring
process; and, moreover, as the constitution is more tried, in cold, than
in warm, weather, and as in cold weather the body exhales less during
the hours of sleep, it is not so injurious to protract our slumbers
beyond the proper period, as it is in the warm months. But in Winter, it
is best for grown persons, in health, to rise as soon as they can see to
dress, and retire so as not to allow more than eight hours for sleep.

It thus appears, that the laws of our political condition, the laws of
the natural world, and the constitution of our bodies, alike demand that
we rise with the light of day to prosecute our employments, and that we
retire wit