t-of-door Air]

But we must not depend altogether on ventilating our houses and our
clothes. We must turn our thoughts toward an outdoor life. The air of
the best ventilated house is not as good as outdoor air. Those who spend
much of their lives in the open enjoy the best health and the greatest
longevity. It is a great advantage to go into camp in summer and to live
in the country as much as possible.

Climate, of itself, is a secondary consideration. Not every one can
choose the best climate in the world, and, after all, the main
advantages of fresh air can be enjoyed in almost any locality. Even in a
city, outdoor air is, under ordinary circumstances, wonderfully
invigorating.

[Sidenote: Dampness]

The common prejudice against damp air greatly exaggerates its evils.
While moderate dryness of air is advantageous, it seems nevertheless
true that to live in damp, even foggy, air out-of-doors is, in general,
more healthful than to live shut up indoors.

[Sidenote: Outdoor Schools]

Observations have shown that the pupils in outdoor and open-window
schools are not only kept more healthy but learn more quickly than those
in the ordinary schools. It is even claimed that tuberculous children in
an outdoor school may make more rapid progress in their studies than the
more normal children in a badly ventilated school. Parents should insist
on fresh air for their children when at school. They should also insist
on outdoor playgrounds.

[Sidenote: Outdoor Recreations]

For themselves, also, they should not neglect outings, picnics, and
visits to parks. Whenever practicable, outdoor recreation should be
chosen in preference to indoor recreation.

[Sidenote: Occupations]

Above all, outdoor occupations should, when possible, be chosen in
preference to indoor occupations, such as working on a farm rather than
in a factory. It would help solve some of the greatest problems of
civilization, if, in consequence of an increased liking for outdoor life,
larger numbers of our population should join the "back-to-the-farm"
movement. Leaving the country for the city is often disastrous even for
the purpose in view, namely to gain wealth. For wealth gained at the
expense of health always proves in the end a bitter joke. The victim
proceeds through the rest of his life to spend wealth in pursuit of
health.

Section IV--Outdoor Sleeping

Unfortunately most people can not live out of doors all of the time, and
many are so si