Sanitary and Social Lectures, etc by Charles Kingsley
page 36 of 220 (16%)
page 36 of 220 (16%)
![]() | ![]() |
|
put the candle out.
Now, how is this? First, what is the difference between the breath you take in and the breath you give out? And next, why has it a similar effect on animal life and a lighted candle? The difference is this. The breath which you take in is, or ought to be, pure air, composed, on the whole, of oxygen and nitrogen, with a minute portion of carbonic acid. The breath which you give out is an impure air, to which has been added, among other matters which will not support life, an excess of carbonic acid. That this is the fact you can prove for yourselves by a simple experiment. Get a little lime-water at the chemist's, and breathe into it through a glass tube; your breath will at once make the lime-water milky. The carbonic acid of your breath has laid hold of the lime, and made it visible as white carbonate of lime--in plain English, as common chalk. Now I do not wish, as I said, to load your memories with scientific terms: but I beseech you to remember at least these two, oxygen gas and carbonic acid gas; and to remember that, as surely as oxygen feeds the fire of life, so surely does carbonic acid put it out. I say, "the fire of life." In that expression lies the answer to our second question: Why does our breath produce a similar effect upon the mouse and the lighted candle? Every one of us is, as it |
|