of the Maremna, which is made by her a tract
for many leagues of almost uninhabitable
land. At the close of the rainy season, when
the sun beats on the damp forests in Northern
India, "everything which has the breath of
life instinctively deserts them. The tigers go
up to the hills; the antelopes and wild hogs
make incursions into the cultivated plain;
and those persons, such as dâk-bearers, or
military officers, who are obliged to traverse
the forest in the intervening months, agree
that not so much as a bird can be heard or
seen in the frightful solitude." Out of what
presence do they fly? They fly before the
rising of the ghostly poisoner. They shun
Malaria, who will assert her sway over those
woods until the days of extreme heat are at
an end.

We have obtained from Doctor Watson's
lectures all the information we are giving on
the subject of the poisonings committed by
Malaria.

Represent heat by fire, and it may be said
that all four elements—we mean the old-
fashioned four—must unite in the production
of Malaria. There must be fire, air, water,
and earth also. If earth were not essential,
then Malaria could board ships out at sea
between the tropics. But she does nothing
of the kind, she only boards them when they
touch at any of her coasts.

But has she nothing vegetable in her
ancestry? Where there is earth subject to
much heat and much moisture, we usually
find rank vegetation, and much vegetable
decay. Therefore it has, from the first, been
said, and is now very generally said, that decay
of vegetable matter is essential to the forming
of Malaria. There is no ague formed among
the rotten cabbage leaves of Covent Garden,
or of costermongers' yards in London. That
is a small fact. Dr. William Ferguson has
brought together more decisive proof that
Malaria may exist where there is not only no
decaying vegetable matter, but no vegetation.

In August 1794, after a very hot and dry
summer, the English army in Holland
encamped at Rosendaal and Oosterhout. The
soil in Rosendaal, the valley of roses, was a
level plain of dry sand, where there was no
vegetation. It was the same at Oosterhout.
To within a few inches of the surface this
sand was percolated with water, of good
quality; that is to say, fit to drink, and not
at all putrid. Upon this ground Malaria
produced intermittent and remittent fevers
in abundance. It was after a dry hot summer
that the British army in Walcheren, over a
soil of the same kind, a fine white sand,
about a third part clay, suffered under the
violence of Malaria pains never to be
forgotten, and "almost unprecedented in the
annals of warfare."

In 1809 several regiments in Spain
encamped in a half-dried ravine that had been
lately the stony bed of a watercourse. It
contained neither vegetation nor mud. The
pools of water standing in the rocks were so
clear that the soldiers eagerly encamped
about them. The place proved pestiferous as
any fen. Several of the men were seized
with violent remittent fever before they
could move from the bivouac next morning.

After the battle of Talavera, the army
retreated along the course of the Guadiana.
The country was so dry for want of rain, that
the river course was no more than a line of
detached pools. The troops along this track
"suffered," says Dr. Ferguson, "from remittent
fevers of such destructive malignity, that
the enemy, and all Europe, believed that the
British host was extirpated."

The river Tagus at Lisbon, about two
miles broad, separates a healthy from a sickly
region. On the healthy side the country is
bare hill and rock, with water-courses. On
the other side, the Alentejo land is quite dry,
flat, and sandy. That side is held in occupation
by Malaria. In and near Lisbon are
many gardens in which stone reservoirs hold
water during the three months' drought,
water foul and putrid, close to the houses and
the sleeping-rooms. These reservoirs do not
breed fever, among people who live and
breathe in their atmosphere; yet one night's
sleep upon the sandy shore of the Alentejo,
where no water at all has been seen for
months—no putrid water ever—would probably
secure to the peasant a strong dose of
remittent fever.

This does not mean to say that the product
of vegetable decomposition is not an unwholesome
thing. It means that it is not Malaria.
All that is required for the production of
Malaria seems to be that an absorbent soil
be soaked with water and then dried. The
higher the drying temperature, and the
quicker the process, the more plentiful and
the more virulent will be the poison
generated.

Malaria springs rather from a surface that
having been wetted has been dried, than from
a surface that continues to be wet. The
edges of a swamp which dry, become wet, or
dry again, according to the season, are more
dangerous than the perpetually wet ground
in the centre. When streams have
overflowed their banks and then retired again, it
is from the dried or half-dried ground on
either side of them that fevers come.

Low damp grounds that have been drying
and producing fevers, become healthy when
the rain sets in that floods them over. Whenever
Malaria has power to poison, she is more
productive of disease and death, agues and
fevers, in hot and dry years, than in years
that are cold and moist. In the West Indies,
in the higher grounds, the cooler parts,
Malaria dispenses poison in its mildest form,
producing agues; lower down, in warmer
tracts, remittent fevers are the common form,
but in the lowest and the hottest parts, the
fever is continued. This fact is curiously
illustrated by one of Dr. Ferguson's examples.