6.- Glimpses of Science. THE TWO BREATHS. bōōn, benefit. ĕl'e-mentş, component parts. ex-haust'ed, consumed, used up. ex-çĕss', unduly large proportion. phys'ie-al, pertaining to Nature. PREPARATORY NOTES. The author of this piece, Rev. Charles Kingsley (1819-1875), was a distinguished English novelist and essayist, and an agreeable writer for the young. His style is popular and interesting. (4) Highland: relating to the Highlands of Scotland. - (5) Grotto del Cane (kä'nā) is Italian for dog's cave. - - (5) Black Hole of Calcutta: a dungeon in Fort William, Calcutta, eighteen feet square, having two barred windows. Here, June 20, 1756, one hundred and forty-six British prisoners were shut up by their Hindu captors for the night. Only twenty-three survived till morning. 1. I call this lesson "The Two Breaths," not merely "The Breath," and for this reason: every time you breathe, you breathe two different breaths; you take in one, you give out another. The composition of these two breaths is different. Their effects are different. The breath which has been breathed out must not be breathed in again. 2. That the breath breathed out is very different from the breath breathed in, may be shown in many ways. For instance, if a child be allowed to get into the habit of sleeping with its head under the bedclothes, and thereby breathing its own breath over and over again, that child will surely grow pale, weak, and ill. Medical men have cases on record of serious disease appearing in children previously healthy, which could only be accounted for from this habit, and which ceased when the habit stopped. 3. Take a second instance, which is only too common. If you are in a crowded room, with plenty of fire and lights and company, with doors and windows all shut tight, how often you feel faint, so faint, that you may require smelling-salts or some other stimulant! The cause of your faintness is, that you and your friends, and the fire and the candles, have been all breathing one another's breaths over and over again, till the air has become unfit to support life. 4. You are doing your best to enact over again the Highland tragedy, when, at a Christmas meeting, thirty-six persons danced all night in a small room with a low ceiling, keeping the doors and windows. shut. The atmosphere of the room was noxious beyond description; and the effect was, that seven of the party were soon after seized with typhus-fever, of which two died. 5. You are inflicting on yourselves the torments of the poor dog who is kept at the Grotto del Cane, near Naples, to be stupefied, for the amusement of visitors, by the carbonic-acid gas of the grotto, and brought to life again by being dragged into the fresh air. Nay, you are inflicting upon yourselves the torments of the famous Black Hole of Calcutta; and if there were no chimney in the room by which some fresh air could enter, the candles would soon burn blue, as they do, you know, when-according to the story-booksghosts appear; your brains would become disturbed; and you yourselves would run the risk of becoming ghosts, and the candles of actually going out. 6. Of this last fact there is no doubt; for if you put a lighted candle into a close box, and, while you take in breath from the outer air, send out breath through a tube into the box, however gently, you will in a short time put the candle out. 7. Now, what is the difference between the breath you take in and the breath you give out? 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 gas. The breath which you give out is an impure air, to which has been added, among other matters which will not support animal life, an excess of carbonic-acid gas. 8. That this is the fact, you can prove for yourselves by a simple experiment. Get a little lime-water at the druggist's, and breathe into it through a glass tube: your breath will at once make the lime-water milky. The carbonic-acid gas of your breath has laid hold of the lime, and made it visible as white carbonate of lime—in plain English, as common chalk. 9. Now, I do not wish 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. 10. I say "the fire of life." Why does our breath produce a similar effect upon animal life and the lighted candle? Every one of us is, as it were, a living fire. Were we not, how could we be always warmer than the air outside of us? There is a process going on perpetually in each of us, similar to that by which coal is burnt in the fire, oil in a lamp, and wax in a candle. To keep each of these fires alight, oxygen is needed; and the products of combustion, as they are called, are more or less the same in each case bonic-acid gas and steam. car 11. These facts justify the expression I just made use of: that the fire and the candles in the crowded room were breathing the same breath as you were. It is but too true. An average fire requires, to keep it burning, as much oxygen as several human beings do; each candle or lamp must have its share of oxygen likewise, and that a very considerable one; and an average gasburner consumes as much oxygen as several candles. All alike are making carbonic-acid gas. 12. The carbonic-acid gas of the fire happily escapes up the chimney in the smoke; but the carbonic-acid gas from the human beings and the candles remains to poison the room, unless it be ventilated. 13. A human being shut up in a room, of which every crack is closed, with a pan of burning charcoal, falls asleep, never to wake again. His inward fire is competing with the fire of the charcoal for the oxygen of the room; both are making carbonic-acid gas out of it; but the charcoal, being the stronger of the two, gets all the oxygen to itself, and leaves the human being nothing to inhale but the carbonic-acid gas which it has made. 14. The human being dies first; but the charcoal dies also. When it has exhausted all the oxygen of the room, it cools, goes out, and is found in the morning half consumed beside its victim. 15. And now, what becomes of this breath which passes from your lips? Is it merely harmful? merely waste? No! The carbonic-acid gas which passes from your lips at every breath is a precious boon to thousands of things which we daily need. Indeed, there is a sort of hint at physical truth in the old fairy-tale of the girl from whose lips, as she spoke, fell pearls and diamonds. 16. For, though you must not breathe your breath again, you may enjoy its fragrance and its color in the lily and the rose. When you walk in a sunlit garden, every word you speak, every breath you breathe, is feeding the plants and flowers around. The delicate surface of the green leaves absorbs the carbonic-acid gas, and parts it into its elements, retaining the carbon to make woody fiber, and courteously returning you |