The republic. [volume] (Washington [D.C.]) 1849-1853, 1850-08-31

Why EPiDEmIcs RACE AT NiGHr.-It was ono
night that 900 persisted in the plague Of London
of 1860 II was at night that the army of SIENNA
cherib was destroyed. Both in England and on
the continent large proportion Of cholera cases in
ts several forms, have occurred between one and
two O'Clock in the morning. The danger Of ex b
posurc 10 tho night air !" has been theme Of ply
sicians from time immemorial; but II il remarka-
able that they have never yet called in the aid Of
chemistry to account for the fact
IL Is at night when the stream Of air nearest the
ground must always be most charged with the par
ticlcs Of animazed matter given out from the skin,
and dolctcrious gases, such carbonic acid gas,
the product Of respiration, and sulpburctted by
drogcn, the product Of the sewers. la the day,
gases and vaporous substances Of all kinds rice in
the air by the rarciactOn OF heat; at night, when
the rarclacton leaves them, they fall by increase
Of gravity, II imperfectly mixed with the atmo-
sphere, while the gases evolved during the night,
instead OF ascending, remain at nearly the same
level. IL IL known that carbonic acid ga1, at low
temperature, partakes nearly Of the nature Of a
fluid, that il may be poured from one vessel into
another IL rises at the temperature at which it ia
e1haled from the lungs; but tie tendency il toward
the floor, the bed of the sleeper in cold and
ventilated rooms.
At Hamburgh, the alarm Of the cholera at night,
in some parts Of the city, was so great that ON
some occasions many refused TO go 90 bed, lest they
should be attacked unawares in their sleep. Sit
ting up, they probably kept their stoves or open
bre-p places burning for the sake Of warmth and
that warmth giving the expansion 20 any delcteri-
Gus gascs present, which would beet promote their
escape and promote their dilutior in the atmo-
sphere, the means of safety we're thus .uncon.
sciously assured. At Sierra Leone, the natives
have practice, in the sicky season, Of keeping
fires constantly burning in their butts at night, as
signing that the fires keep away tho evil spirits "a
which, in their ignorance, they attribute fever md
ague Lattcrly, Europeans have begun 10 adopt
tho practice, and those who have tried IL as
cert that they have entire impuniy from the trop-
ical fevers to which they were formerly subject
In the epidemcs of the middle ages, fires used to
be lighted in the streets for the publication OF the
air; and in the plague Of London, Of 1865, fires in
the streets Mt one time kept burning inces-
sanity, tall estinguishcd by violent storm of rain.
Latterly, trains Of gunpowdcr have been fired, and
cannon discharged, for the same object; but II is
obvious that these measures, although sound in
principle, must necessarily, out Of doors, be on
too small a scale, rs measured against an ocean OF
atmospheric air, TO produce any sensible effect.
Within doors, however, the case Ia different
II is quite possible TO heat room TO produce a
rareaction and consequent dilution of any malig
nant gases il may contain; and IL is Of course the
air OF the room alone at night, which comes into
immediate contact with the lungs of person sleep
ing.-Westninsfr Repis,o.