Then we have to breathe it.
If you open the window at the top, it will let out the bad air, and you
will not feel a draught. It is not often so very cold that you cannot
bear the window open, even a little way from the top, and that is the
best way of airing a room.
This is just as necessary by night as by day. People who shut in the bad
air, and shut out the good air, all night long, can never expect to
awake refreshed, feeling better for their sleep.
What becomes of the carbonic acid gas which the body throws off through
our breath? Can any thing pick the carbon and oxygen in it apart, and
make them fit for us to use again?
Yes. Every plant, every green leaf, every blade of grass, does that for
us. When the sun shines on them, they pick the carbon out and send back
the oxygen for us to breathe. They keep the carbon and make that fit
for us and animals to eat.
The grass makes the carbon fit for sheep and cows, and then we eat their
flesh or drink their milk; and the corn makes the carbon fit to eat; so
do potatoes, and all the other vegetables and fruits which we eat. Is
not this a wonderful arrangement?
But perhaps you think, considering what an amazing number of people
there are in the world, besides all the animals--for all creatures that
breathe, spoil the air just as we do--there can hardly be trees and
plants enough to set all the air right again.
Pages:
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138