The Kenosha telegraph. [volume] (Kenosha, Wis.) 1860-1888, 1872-06-13
THE ORIGIN OF MALARIA.
BY DANIEL VAUGHAN.

nA D~AANAA1AA AOUhAN.
While excessively moist lands in warm
climates are known to be unfavorable to
health, no adequate cause for the evils is
to be found IN the local variation in the
gaseous constituents of the air, or In anv
direct Influence of the aqueous vapor
which it contains. To remove the mys
telies connected with the insalubrity of
such localities, the course of experimental
inquiry has recently been directed to a
search for the organic matter in the air
and water; but an examination of the
sources from which this matter is derived
may contribute much to reveal it's pecu
liar characters and its effects on the hu.
man frame For the greater portion of
the carbonaceous matter which it contains
the atmosphere is Indebted to the vegeta
bic kingdom; and to the great repository
Of carbon We may first look for The source
OF marsh poison, which is generally re
garded as having vegetable origin.
Though serious evils may be justly i'm,
puted to the dust which occasionally float
around us, they must be excluded from
consideration IN inquiries respecting the
insalubrity OF marshes. In these perma
nent abodes Of moisture, dust cannot be
expected t. rise from the ground and its
solid PARTICLES would be only removed
from the air by those rains which Obser
Vation proves to be instrumental in de
veloping he activity of malaria. Aka
loids, vegetable acids, and the salts that
they form, might mingle with the fresh
waters Of cur lands; yet they cannot be
expected to pass into the air in quantity
sufficient TO effect in a serious degree the
economy Of animal life. But the volatile
oilse emitted by.living and decaying plants,
have the greatest tendency to charge the
air with their vapors; and as the extent
OF this lmpregnation depends chiefly on
heat, they appear to correspond to those
malariouS carnations which marshes are
ready to send forth in obedience 10 the
elevation Of temperature.
From the limited scale on which they
are produced on our globe, thase vol =
atlle oils could have little influence on
the condition of human health If they
were uniformly diffused through the at
mosphere, CT even if they entered it by
vegetable exhalation alone But, from
their slight olubility in water, they are
collected during rains into low marshes
and, under the influence of heat, the air
IN these localities must be filled with the
Vap)rs OF the volatile organic matter pro
dUced on the highlands around them. The
course OF nature in this case is very SINH
lar to that exhibited on small scale in
obtaining volatile oils or perfumes from
different parts OF plants by acqueous dis
On distillirg with water the
products in which they are
contained, the essential oils pass over
with the steam, and are obtained by cen
dcnsatlon in 2 pure or in concentrated
form. Although it is not always necessary
that they should dissolve in the fluid be |
fore yolatilizing, yet the ISOLATION general.
~ takes place; and it contributes to the
success Of the operation in cases where |
5he essential oils form but small part Of
ihe materials from which they are manu-
featured. In obtaining the ferment oils,
the leaves and other parts of plants capa |
bic OF affording them, require to be steep.
ed in water for some days and dstilla-
lion is not performed until the odor Of
the fluid gives Indication that the oils |
have been generated. The mode gener
Ally adopted for obtaining these volatile
principles from vegetable matter depends |
IN their slight solubility in Water, and on
he manner in which they are affected by
In increase OF temperature
From these results it is easy to trace
he inevitable course of similar operations
in nature on far more extern
i've scale. Of the rain which falls during
warm seasons, large part comes into re-
Oeated contact with numerous vegeta BILE |
Orms as 1t descends along the leaves ana !
branches of trees, or moves through the |
lowers and heritage OF verdant fields SO
hat on reaching the valleys, the water
must be contaminated with the essential |
'lls OF living plants, and with the ferment
'lls OF their decaylng parts. In this man
Ter marsh, an enclosed lake, or pond,
becomes the receptacle of a large portion
II the volatile organic matter g nerated
within the basin from which its waters
re collected. The volatile oils, which,
IN the occurrence Of cool and heavy rains,
re thus concentrated from n wide ar8a
nto marsh, change into vapor IS the
water becomes warm: and they will be
most ready TO contaminate the air over
UGH permanent abodes of moisture dur
ng the intense heat Of the summer.
The relation which [ have traced be-
ween the processes of nature and Of art
or concentrating into limited space the
iffusible oils of plants, does not require ,
hat the water of marsh should be sub
ected to boiling heat. This will APP
ear evident from well known facts and
principles respecting Vaporization and,
Iithout insisting on the rigorous accuracy
f Dalton's law, we may use it to deter
alne approximately the amount of these
olatiIe oils, which at certain tempera t
are, can exist as vapor in given volume
f air, or, rather, in given space This s
lay be estimated, theoretically, from the |
oiling point Of the oil and from the den r