Health and Education | Page 9

Medical men have cases on record
of scrofula appearing in children previously healthy, which could only

be accounted for from this habit, and which ceased when the habit
stopped. Let me again entreat your attention to this undoubted fact.
Take another instance, which is only too common: If you are in a
crowded room, with plenty of fire and lights and company, 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 just the same as that of the mouse's fainting in the box: you
and your friends, and, as I shall show you presently, the fire and the
candles likewise, having been all breathing each other's breaths, over
and over again, till the air has become unfit to support life. You are
doing your best to enact over again the Highland tragedy, of which Sir
James Simpson tells in his lectures to the working-classes of Edinburgh,
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. You are inflicting on yourselves the torments
of the poor dog, who is kept at the Grotto del Cane, near Naples, to be
stupified, 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 was no chimney in the room, by
which some fresh air could enter, the candles would soon burn blue--as
they do, you know, when ghosts appear; your brains become disturbed;
and you yourselves run the risk of becoming ghosts, and the candles of
actually going out.
Of this last fact there is no doubt; for if, instead of putting a mouse into
the box, you will put a lighted candle, and breathe into the tube, as
before, however gently, you will in a short time 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 were, a living fire.
Were we not, how could we be always warmer than the air outside us?
There is a process going on perpetually in each of us, similar to that by
which coals are burnt in the fire, oil in a lamp, wax in a candle, and the
earth itself in a volcano. To keep each of those fires alight, oxygen is
needed; and the products of combustion, as they are called, are more or
less the same in each case--carbonic acid and steam.
These facts justify the expression I just made use of--which may have
seemed to some of you fantastical--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 in the grate 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 gas-burner--pray attend to this, you who live in rooms lighted
with gas--consumes as much