Daily Kennebec journal., 1913-12-30
WE REeREATHE SOME AIR.
Even the Sleeping Perehss Do Nss
Give Us All Fresh Ozone.

Under ordinary conditions OF breath.
ing some of the expired air must pe
drawn back again into the lungs. a
few experiments to determine the pro-
portion of the breath that Is reinspdred
have been made during the last ID
years, but no really thorough study
of the question was carried out until
the recent work of Crowder. This in
yestisator has studied by ingenious
methods the effect Of change OF po-
sition. body motion. different types OF
breathing and different temperatures
and in addition has determined the
conditions that obtain on the sleeping
porch and in the open air.
His conclusions are that d) . pe>
son remaining quiet and indoors win
Immediately rebreath from to . per
cent. Of his own expired air: t2) when
lying in bed the percentage is higher
rising to from to 10 per cent, depends
ing on the position assumed while
sleeping. Nor does sleeping In the
open air insure pure air for breathing.
The same influences here produce the
Same relative results that they do in@
side. When one buries his head be-
tween pillow and bedclothes for the
sake of warmth, reinspiration is inev.
liable, and it Is not necessarily small
III amount"
The significance OF this study I'd
connection with questions Of ventiias
ton 10 obvious. Since even under the
most favorable conditions we cannot
avoid drawing back into the lungs
some of the air that has Just passed
out of them, not much importance can
be attached to the slight variations
in carbonic acid gas which occur In
the air of rooms. A little dseper
breathing seems to be the utmost ply.
siologic effect that could be caused.
These experiments also furnish addi-
tional evidence against the theory thai
efficient ventilation consists in the
chemical purity of air, in its freedom
from "a toxic organic substance" Even
were a poisonous substance present In
the expired ARA fact no experiment.
er has yet been able to demonstrate
the human body under everyday con-
ditiens Is apparently well able to ad.
just itself to the reinhalation Of this
hypothetic substance, since a consid.
erahle quantity of the expired air ID
always taken back into the lungs.
The failure of many expensive ven.
tilation systems to confer the com.
fort expected from them has been due
to neglect of such facts. The attempts
to renew the air by displacing g
certain volume at regular intervals
We're based on the theory that good
ventilation was due TO freedom from
the chemical constituents of expired air.
We row know that this practice did
not achieve the end aimed at, because
the essential factors In good ventiIa-
lion are not freedom from carbonie
acid gas or from mythical organic
poison. but are GOODNESS. dryness and
motion. Crowder's work brings the
old and new theories of ventilation
into sharp contrast The theory OF
displacement does not sufficiently take
into consideration that all animals
possessing lungs ventilate them on q
very simple principle of dilution; nor
does the pure air theory sufficiently
consider that the air of the lungs al
ways remains highly contaminated
with their own excretory gases, and
that there is such an effective barrier
as the dead space against the lower
ing of the contamination. ."--Americau
Medical Association.