out of doors proverbially synonymous with robust health? Why is it
that a superior vitality, and a singular exemption from disease,
notoriously distinguish dwellers in the open air, by land or sea?
Without disparaging the virtues of exercise or of bracing temperature,
indispensable as these are for the recuperation of enfeebled
constitutions, we must admit that among the native and settled
inhabitants of the open air high health is the rule in warm climates
as well as in cold, and with the very laziest mortals that bask in the
sun, or loaf in the woods. The fact is that simple vegetative health
seems to be nearly independent of all other external conditions but
that of a pure natural diet for the lungs. Man in nature seems to
thrive as spontaneously as plants, by the free grace of air, earth,
and sun. On the other hand, the very diseases from which houses are
supposed to defend us--that most numerous class resulting from
colds--are the special scourge of the lives that are most carefully
shielded from their commonly supposed cause--exposure to the open air.
Those diseases diminish, and entirely disappear, just so far as
exposure in the pure and freely moving air becomes complete and
habitual. Soldiers, inured to camp life, catch cold if they once sleep
in a house; and, generally speaking, the inhabitants of the free air
contract colds _only_ by exposure to confined exhalations from their
own or other bodies, within the walls of houses. The explanation of
this is plain and simple: Carbonic acid detained within four walls
accumulates in place of the breath of life--oxygen--and narcotizes the
excretory function of the skin. The moment that this great and
continual vent of waste and impurity from the system is obstructed,
internal derangement ensues in every direction. All hands, so to
speak, are strained to extra duty to discharge the noxious
accumulation. The lungs labor to discharge the load thrown back upon
them, with hastened respiration, increased combustion, and feverish