arbonic acid and water,
which escapes as breath. As fast as we breathe out, carbonic acid and
water leave the blood; as fast as we breathe in, oxygen enters it. The
oxygen is sent out in the arteries to make the rubbish of the body into
gas and vapor, so that the veins may bring it back and get rid of it. The
burning of rubbish by oxygen throughout our frames is the fire by which
our animal heat, is kept up. At least this is what most philosophers
think; though doctors differ a little on this point, as on most others, I
hear. Professor Liebig says, that our carbon is mostly prepared for
burning by being first extracted from the blood sent to it--(which contains
much of the rubbish of the system dissolved)--in the form of bile, and is
then re-absorbed into the blood, and burnt. He reckons that a grown-up man
consumes about fourteen ounces of carbon a day. Fourteen ounces of
charcoal a day, or eight pounds two ounces a week, would keep up a
tolerable fire."

"I had no idea we were such extensive charcoal-burners," said Mr. Bagges.
"They say we each eat our peck of dirt before we die--but we must burn
bushels of charcoal."

"And so," continued Harry, "the professor calculates that we burn quite
enough fuel to account for our heat. I should rather think, myself, it had
something to do with it--shouldn't you?"

"Eh?" said Mr. Bagges; "it makes one rather nervous to think that one is
burning all over--throughout one's very blood--in this kind of way."

"It is very awful!" said Mrs. Wilkinson.

"If true. But in that case, shouldn't we be liable to inflame
occasionally?" objected her husband.

"It is said," answered Harry, "that spontaneous combustion does happen
sometimes; particularly in great spirit drinkers. I don't see why it
should not, if the system were to become too inflammable. Drinking alcohol
would be likely to load the constitution with carbon, which would be fuel
for the fire, at any rate."

"The deuce!" exclaimed Mr. Bagges, pushing his brandy-and-water from him.
"We had better take care how we indulge in combustibles."

"At all events," said Harry, "it must be bad to have too much fuel in us.
It must choke the fire, I should think, if it did not cause inflammation;
which Dr. Truepenny says it does, meaning, by inflammation, gout, and so
on, you know, uncle."

"Ahem!" coughed Mr. Bagges.

"Taking in too much fuel, I dare say, you know, uncle, means eating and
drinking to excess," continued Harry. "The