a close one, and
well defended by a railing, cotton will seldom expose to danger. Still,
as has been already said, the introduction of heated air from another
apartment, whenever it can possibly be afforded, is incomparably better
than either stoves or fire-places.

Dr. Dewees is fully persuaded that the excessive heat of nurseries has
occasioned a great mortality among very young children. "In the first
place," he says, "it over-stimulates them; and in the second, it renders
them so susceptible of cold, that any draught of cold air endangers
their lives. They are in a constant perspiration, which is frequently
checked by an exposure to even an atmosphere of moderate temperature."
If this is but to repeat what has been already said, the importance of
the subject seems to be a sufficient apology.

CHAPTER III.

VENTILATION.

General ignorance of the constitution of the atmosphere. The subject
briefly explained. Oxygen gas. Nitrogen. Carbonic acid. Fires, candles,
and breathing dependent on oxygen. Danger from carbonic acid. How it
destroys people. Impurity of the air by means of lamps and candles.
Other sources of impurity. Experiment of putting the candle under the
bed-clothes. Covering the heads of infants while sleeping--its dangers.
Proportions of oxygen and nitrogen in pure and impure air. No wonder
children become sickly. Particular means of ventilating rooms. Caution
in regard to lamps. Washing, ironing, cooking, &c., in a nursery. Their
evil tendency. Fumigation--camphor, vinegar.

Few people take sufficient pains to preserve the air in any of their
apartments pure; for few know what the constitution of our atmosphere
is, and in how many ways and with what ease it is rendered impure.

It is not my purpose to go into a learned, scientific account in this
place, or even in this work, of the constitution of the atmosphere. A
few plain statements are all that are indispensable. The atmosphere
which we breathe is composed of two different airs or gases. One of
these is called oxygen, [Footnote: Oxygen gas is the chief supporter of
combustion, as well as of respiration. It is the vital part, as it were,
of the air. No animal or vegetable could long exist without it. And yet
if alone, unmixed, it is too pure and too refined for animals to
breathe. Nitrogen gas, on the contrary, while alone, will not support
either respiration or combustion; mixed, however, with oxygen, it
dilutes it, and in the most happy