the highest possible degree, his health
and longevity. We must avoid breathing over the carbonic acid gas
contained in the tight or unventilated rooms in which we labor or
remain for a long time, whether parlors, school-rooms, counting-rooms,
bed-rooms, shops, or factories. The individual who lives most according
to nature--who observes with most care the laws of life and health--must
necessarily throw off much carbonic acid from his lungs, if not from his
skin. It does not follow, however, that because this gas is formed we
are obliged to inhale it. We may change our position, change our
clothing, ventilate our rooms of all sorts, shake up our bed-clothing
often and air our bed, and use clean, loose, and porous clothing by
night and by day. We may thus very effectually guard against injuries
from a very injurious agent.

[18] From Dr. William A. Alcott's Tract on Breathing Bad Air.

"One thing should be remembered in connection with this subject which is
truly encouraging. The more we accustom ourselves to pure air, the more
easily will our lungs and nasal organs detect its presence. He who has
redeemed his senses and restored his lungs to integrity, like him who
has redeemed a conscience once deadened, is so alive to every bad
impression made upon any of these, that he can often detect impurity
around or within him, and thus learn to avoid it. It will scarcely be
possible for such a person long to breathe bad air, or nauseous or
unwholesome effluvia, without knowing it, and learning to avoid the
causes which produce it. Such a person will not neglect long to remove
the impurities which accumulate so readily on the surface of his body,
or suffer himself to use food or drink which induces flatulence, and
thus exposes either his intestines or his lungs, or the lungs of others,
to that most extremely poisonous agent, sulphureted hydrogen gas. Nor
will he be likely to permit the accumulation of filth, liquid or solid,
around or in his dwelling. There are those whose senses will detect a
very small quantity of stagnant water, or vinegar, or other liquids, or
fruit, or changed food in the house, or even the presence of those
semi-putrid substances, wine and cider. But some will indeed say that
such integrity of the senses would be an annoyance rather than a
blessing. On the same principle, however, would a high degree of
conscientiousness in regard to right and wrong in moral conduct be a
curse to us. If it be desira