ts]

There is an unreasonable prejudice against air in motion. A gentle draft
is, as a matter of fact, one of the best friends which the seeker after
health can have. Of course, a strong draft directed against some exposed
part of the body, causing a local chill for a prolonged time, is not
desirable; but a gentle draft, such as ordinarily occurs in good
ventilation, is extremely wholesome.

[Sidenote: Air and Catching Colds]

It goes without saying that persons unaccustomed to ventilation, and
consequently over-sensitive to drafts, should avoid over-exposure while
they are in process of changing their habits. But after even a few days
of enjoyment of air in motion, with cautious exposure to it, the
likelihood of cold is greatly diminished; and persons who continue to
make friends with moving air soon become almost immune to colds.

The popular idea that colds are derived from drafts is greatly
exaggerated. A cold of any kind is usually a catarrhal disease of germ
origin, to which a lowered vital resistance is a predisposing cause.

The germs are almost always present in the nose and throat. It is
exposure to a draft plus the presence of germs and a lowered resistance
of the body which produces the usual cold. Army men have often noted
that as long as they are on the march and sleep outdoors, they seldom or
never have colds, but they develop them as soon as they get indoors
again. See SUPPLEMENTARY NOTES, "Avoiding Colds."

Of course, one must always use common sense and never grow foolhardy. It
is never advisable that a person in a perspiration should sit in a
strong draft.

[Sidenote: Windows]

The best ventilation is usually to be had through the windows. We advise
keeping windows open almost always in summer; and often open in winter.

One should have a cross-current of air whenever practicable; that is, an
entrance for fresh air and an exit for used air at opposite sides of the
room. Where there can not be such a cross-current, some circulation can
be secured by having a window open both top and bottom.

[Sidenote: Window-boards]

In winter, ventilation is best secured by means of a window-board. This
is a board the edge of which rests on the edge of the window-sill, the
ends being attached firmly to the window-frame. It affords a vertical
surface three or four inches high and situated three or four inches in
front of the window, so as to deflect the cold air upward when the
window is slightly opened.