persons demands more oxygen, and throws off more carbonic acid, and
is distressed when the supply fails. But the one reduced by bad air
feels little inconvenience, because all the functions of life are so
slow that less oxygen is needed, and less carbonic acid thrown out.
And the sensibilities being deadened, the evil is not felt. This
provision of nature prolongs many lives, though it turns vigorous
constitutions into feeble ones. Were it not for this change in the
constitution, thousands in badly ventilated rooms and houses would
come to a speedy death.

One of the results of unventilated rooms is _scrofula_, A distinguished
French physician, M. Baudeloque, states that:

"The repeated respiration of the same atmosphere is _the_ cause of
scrofula. If there be entirely pure air, there may be bad food, bad
clothing, and want of personal cleanliness, but scrofulous disease can
not exist. This disease _never_ attacks persons who pass their lives in
the open air, and always manifests itself when they abide in air which
is unrenewed. _Invariably_ it will be found that a truly scrofulous
disease is caused by vitiated air; and it is not necessary that there
should be a prolonged stay in such an atmosphere. Often, several hours
each day is sufficient. Thus persons may live in the most healthy
country, pass most of the day in the open air, and yet become scrofulous
by sleeping in a close room where the air is not renewed. This is the
case with many shepherds who pass their nights in small huts with no
opening but a door closed tight at night."

The same writer illustrates this, by the history of a French village
where the inhabitants all slept in close, unventilated houses. Nearly
all were seized with scrofula, and many families became wholly extinct,