GEOGRAPHICAL DISTRIBUTION.
Salt, fortunately for us, is a commodity remarkably easy to obtain;
almost everyone knows it is in great abundance in the ocean,[30] and
there are inexhaustible supplies of it in the earth; it is also present
in some rivers, and in no inconsiderable quantity. Mr. John Ashley, in
the _Quarterly Journal of the Chemical Society_, in his “Analysis of
Thames Water,” tells us the exact amount:
COMPOSITION OF THAMES WATER AT LONDON BRIDGE IN GRAINS PER GALLON
OF 70,000 GRAINS.
Carbonate of Lime 8·1165
Chloride of Calcium 6·9741
Chloride of Magnesium ·0798
Chloride of Sodium (salt) 2·3723
Sulphate of Soda 3·1052
Sulphate of Potash ·2695
Silica ·1239
Insoluble Organic Matter 4·6592
Soluble Organic Matter 2·3380
——————
28·0385
We may account for this great proportion of salts by the fact that
the Thames collects its water from the drainage of comparatively soft
and soluble rocks; we should also remember the vast amount of refuse
organic and inorganic matter which is being continually thrown into
this river; and we must also call to mind that it is nothing more
or less than the main sewer which receives the ordure of the modern
Babylon.[31]
We may naturally suppose that in those rivers which flow through
sparsely inhabited countries, where there is little or no traffic,
the amount of saline matter would be next to nothing, and probably
not a trace would be discovered. In a river like the Thames, owing
to the vast quantity of its shipping, the great percentage which Mr.
John Ashley has given us need not afford the least surprise. Sea-water
is deficient in its proper proportion of salt at the mouths of great
rivers, where the volume of fresh water displaces that which properly
belongs to the sea, and therefore a river does not obtain much saline
matter from that source.
Before we pass on to consider the geographical distribution of salt,
we will just cursorily glance at the position it occupies in the
vegetable world. It is present in all plants growing near the sea,
and in variable quantities in some of those which are in or near
districts where the soil is mixed with salt; though its place is taken
by potash when they grow inland. Dr. Balfour writes as follows: “Soda
and potash occur abundantly in plants. They are taken up with the soil
in combination with acids. Those growing near the sea have a large
proportion of soda in their composition, whilst those growing inland
contain potash. Various species of salsola, salicornia, halimœnenum,
and kochia yield soda for commercial purposes and are called halophites
(ἁλς, salt, and φυτὸν, plant). The young plants, according to Göbel,
furnish more soda than the old ones. There are certain species, as
Armeria maritima, Cochlearia officinalis, and Plantago maritima, which
are found both on the seashore and high on the mountains removed from
the sea. In the former situation they contain much soda and some
iodine; while in the latter, according to Dr. Dickie, potash prevails
and iodine disappears.”
Soda being present in those plants growing near the sea, and potash in
those which are inland, are two points well worthy of notice, and which
we will now discuss. The number of vegetables which are cultivated
near the coast shrink into insignificance when compared with those
which grow inland; and naturally the markets are supplied with inland
produce on account of a larger supply, therefore the consumption of
those vegetables containing potash is in the same ratio. This being
unquestionably the case, we ought, on that account alone, to use
salt freely with our vegetable food in order to supply that which is
absent, arising from the difference of locality and dissimilarity of
the atmosphere. I shall enter fully into the relation salt bears to
vegetable food while it is going through the process of digestion
further on, when we come to consider the effects which food salted
beforehand has upon the system when continued for any length of time,
with little or no variation, which dietary is supposed to be the sole
cause of the attacks of scurvy on board ship.
The sea is that grand reservoir which supplies the earth with its
fertility; and the air and sun are mighty engines which work without
intermission to raise the water from this inexhaustible cistern. The
clouds, as aqueducts, convey the genial stores along the atmosphere,
and distribute them in seasonable and regular proportions through all
the regions of the globe.
With what difficulty do we extract a drop of perfectly sweet water from
this vast pit of brine! Yet the sun draws off, every moment, millions
of tons in vaporous exhalations, which, being securely lodged in the
clouds, are sent abroad sweetened and refined, without the least
brackish tincture or bituminous sediment; sent abroad upon the wings of
the winds to distil in dews and rain, to ooze in fountains, to trickle
along in rivulets, to roll from the sides of mountains, to flow in
copious streams amid burning deserts and populous kingdoms, in order
to refresh and fertilise, to beautify and enrich, every soil in every
clime.
Though the ocean is salt, yet certain seas do not contain so much as
others; my reader must not therefore conclude that the chloride of
sodium, or salt, is equally diffused in sea-water, for the atmosphere
receives a larger or lesser amount by reason of evaporation. Dr. Draper
writes that the “temperature of the Mediterranean is twelve degrees
higher than that of the Atlantic, and since much of the water is
removed by evaporation, it is necessarily more saline than that ocean.”
It is said that the southern seas are slightly more salt than the
northern, the reason for which phenomenon has not been, as yet,
satisfactorily explained.
It is strange that salt should determine the colour of the sea, and
that for centuries the cause of this peculiar natural phenomenon of
the ocean should have been a closed secret even to men of science.
Even from the earliest times, the origin of this marine peculiarity
has attracted the attention and wonder of navigators; yet, strange to
say, it has only been discovered within the last few years. The many
expeditions which have been despatched by the Governments of England,
Germany, and others, for the express purpose of oceanic discovery, have
been the means of solving a question which has perplexed all races of
seamen from the time of the Phœnicians, and which astonished Columbus
on his voyage to the Indies.
These recent scientific investigations have proved that the proportion
of salt held in solution by sea-water determines its blue or green
appearance, and also its specific gravity; consequently, when the water
is blue, we may conclude that it holds a much greater proportion of
salt; when it is green, it is indicative that there is a decrease.
There is one phenomenon which is peculiarly interesting. There are two
kinds of ice floating in the Arctic and Antarctic seas—the flat ice and
the mountain ice. The one is formed of sea-water, the other of fresh.
The flat or driving ice is entirely composed of salt water, which, when
dissolved, is found to be salt, and is readily distinguished from the
mountain or fresh-water ice by its whiteness and want of transparency.
This ice is much more terrible to mariners than that which rises in
lumps. A ship generally can avoid the one, as it is seen at a distance;
but it frequently gets in amongst the other, which, sometimes closing
with resistless force, crushes the doomed vessel to pieces.
The surface of that which is congealed from the sea-water is not only
flat, but quite even, hard, and opaque, resembling white sugar, and
incapable of being slid upon.
Salt is found in variable quantities in different countries, and in
various conditions; in one part it may be found as a huge mountain, in
which there are dark and lofty caverns; in others it is deposited in
marshes and lakes, and in others in deep mines, many hundreds of feet
beneath the surface of the earth.
In some countries there are vast quantities of rock or fossil salt.
Salt has been divided into _three_ kinds: native or rock salt; common
or sea salt, also called white-salt; and bay-salt. Under the title
of bay-salt are ranked all kinds of common salt, extracted from
the water, wherever it is dissolved by means of the sun’s heat and
the operation of the air. If sea-water is evaporated by means of a
gentle heat we also obtain what is known as bay-salt. Common salt, or
sea-salt, or white-salt, which is extracted from the sea, is composed
of hydrochloric acid, saturated with soda, and is found in salt water
and salt-springs, also in coal and gypsum-beds. “The sea itself, if
desiccated, would afford a bed of salt five hundred feet thick, one
hundred for every mile.”
In England, and especially in Cheshire, there are large salt-mines,
at Nantwich and Middlewich, which have existed ever since the Roman
occupation of Britain; and in the year 1670 the Staffordshire
salt-mines were discovered, and accordingly excavated. Those in
Cheshire have been renowned for centuries; their great extent is such
that the surface has subsided on account of its being undermined for so
many miles.
“In England, the Trias is the chief repository of salt, or chloride
of sodium; and brine-springs, which are subterranean streams of water
impregnated with salt from percolating through saliferous strata,
are abundant in the great plain of the red marls and sandstones of
Cheshire. The salt, however, is not uniform in extent, but occupies
limited areas.” The saliferous strata of Northwich present the
following series:
1. Uppermost calcareous marl 15 feet
2. Red and blue clays 120 ”
3. Bed of rock-salt 75 ”
4. Clay, with veins of rock-salt 31 ”
5. Second bed of rock-salt 110 ”
Droitwich, in Worcestershire, which is situated nearly in the centre
of the county, has been celebrated for the production of salt from its
brine-springs from the time of the Romans, who imposed a tax on the
Britons, who, it appears, worked the mines; and also made salt a part
of the pay of their soldiers’ _salarium_, or salary.[32] Ever since,
this inexhaustible fountain of saline water has continued flowing up,
and yielding salt in undiminished quantities. It is very likely that
the manufacture is coëval with the town itself; but it was not till
the year 1725 that the strong brine for which it is now celebrated was
discovered. From one spring, even, the enormous amount of one thousand
tons of salt are obtained every week. At the depth of thirty or forty
feet is a bed of hard gypsum, about one hundred and fifty feet in
thickness; through this a small hole is bored to the stream of brine,
which is about twenty-two inches in depth, and beneath this is the
rock-salt. The brine rising quickly through the aperture is pumped into
a capacious reservoir, whence it is conveyed into iron boilers for
evaporation. It is supposed to be much stronger than any other in the
kingdom, containing above one-fourth part its weight of salt. “One of
the shafts is sunk to a depth of nearly five hundred feet, and passes
through four layers of salt, eighty-five feet in aggregate thickness.
Some of the beds of salt in Cheshire are from seventy to one hundred
and twenty feet in thickness;” and it is sometimes so hard that it
requires to be blasted with gunpowder.
In those districts where the marls of the Trias are covered by other
beds, and the salt-springs force their way through the superincumbent
deposits to the surface, these solutions of the chloride of sodium
undergo a chemical change, acquiring other properties, and are then
called mineral waters. The Cheltenham waters originate thus.[33]
Beneath the town of Cheltenham lie the Triassic deposits, the
reservoir of the rock-salt and brine-springs, which generate the
mineral waters, and from which they derive their saline ingredients.
In their passage to the surface they go through various modifications,
by reason of the superincumbent beds of Lias, which are impregnated
with iron pyrites and the sulphate of lime. From the analyses of
these waters, it appears that their principal constituents are the
chloride of sodium (muriate of soda), or sea-salt, and the sulphates of
soda and magnesia. Sulphate of lime, oxide of iron, and the chloride
of magnesium are present in some wells only, and in much smaller
quantities. Besides these ingredients, _iodine_ and _bromine_ have
been detected by Dr. Daubeny, who instituted experiments to ascertain
whether these two active principles, which the French chemists had
recently discovered in modern marine productions, did not exist in
mineral waters issuing from strata formed in the ancient seas. As the
saline springs of the red marls rise up through the Lias they undergo
certain chemical changes. From the decomposition of the sulphate of
iron which takes place, a vast quantity of sulphuric acid must be
generated, which, reacting on the different bases of magnesia, lime,
etc., contained in the strata, forms those sulphates so prevalent in
the higher or pyritous beds of the Lias; the oxide of iron being at the
same time more or less completely separated. By this means the mineral
waters, which are probably mere brine-springs at the greatest depths,
acquire additional medicinal qualities as they ascend to the places
whence they flow. At the same time, it must be borne in mind that fresh
water is continually falling from the atmosphere upon the surface of
the Lias clays, and percolating through the uppermost strata.[34]
The medicinal properties which are peculiar to these mineral waters
will be considered further on, when we come to discuss the action of
salt on the system, in health and disease, and the restorative results
which are due solely to its instrumentality.
The salt district is in the line which joins the Severn, the Dee, and
the Mersey, and doubtless once consisted of lakes flooded at every
tide, which, drying at certain seasons and at low tides, deposited beds
of salt, from Droitwich in Worcestershire, through Nantwich, to the
Mersey; brine-springs flowing over beds of salt, or rock-salt, being
found at different places on the entire line.
In the year 1863 a bed of rock-salt was discovered near the mouth of
the Tees, at Middlesborough, and also on the Durham side of the river.
The boring at Middlesborough showed that it was about 100 feet in
thickness. Of late, borings have been made near Port Clarence, on the
Durham side, but with what result I am not informed.
Scotland, as well as Ireland, is deficient in the more recent
formation; for salt, as well as chalk, does not occur. Both are
entirely absent; but geologists inform us that at one time chalk _did_
exist, judging from the presence of flints in considerable quantities
in Aberdeenshire, which they say affords unequivocal evidence of the
former presence of cretaceous strata now integrated; and they account
for it thus: the soft chalk being exposed to the action of the rain
and storms, has been gradually washed away, while the flints which
were embedded in it still remain. If this hypothesis is correct, that
at one time chalk existed and is now absent, we may by inference,
though we possess no evidence, presume that salt likewise, at some
period or other, was present in this part of the United Kingdom.
Chalk being entirely composed of the accumulation of marine shells
ground to impalpable powder, which has been gradually consolidated,
and being very rich in organic remains of shells, star-fish, sponges,
fishes, and lizards, must have been deposited by sea-water, as its
various ingredients indicate; therefore, during its deposition, salt,
if originating from sea-water, must of necessity have left some marks
characteristic of itself, in conjunction with the chalk; both being,
more or less, intimately connected with sea-water, though the formation
of one may not have been simultaneous with the formation of the
other.[35]
In our lately acquired “gem of the sea,” Cyprus, there have been
found extensive lakes of salt near Larnaca, the capital, so that this
liberally-abused island possesses at least something which may prove
of pecuniary value to its present owners. Being for several centuries
under the benighted rule of the Turk, this staple of commerce has been
entirely neglected, so as not to have been of the slightest use to the
inhabitants or to the greedy pachas.
In the south of Western Australia there are vast salt marshes which
only require to be worked so as to become the means of enriching
the colonists, and indirectly attracting emigrants to this hitherto
unprofitable portion of a dependency of England. The principal, which
is called Lake Austen, is 1400 feet above the level of the sea.
Salt is also to be found in our Indian Empire, in Rajpootana and
elsewhere, and is of considerable value to that country, especially
while it remains in the hands of the enterprising European; according
to Mr. Wynne, there is a salt range which extends from Kalabagh to
a point north of Tank. After acquainting us with its geographical
position, he says: “The coincidence between the physical features and
the geological structure of the ground is intimate, the axial lines
of the mountains carrying on the Salt Range feature being also axes
of anticlinals lying for the most part along the scarped acclivities
presented towards the Indus plains. These plains are part of the great
_quasi-desert_ flat over which the Indus has in past times capriciously
wandered towards the Arabian Sea. Whether they are due in any degree to
marine explosion is uncertain, though the sea may very possibly once
have covered the low ground in question. The ridges of the Salt Range,
as they exist at present, doubtless mark the same great later, or
post-tertiary, period of mountain-forming activity, in which originated
not only the remainder of the Salt Range, but also the Western Himalaya
and the Suliman and Afghan mountains.” When we come to consider the
geological bearings of salt, and its presumed origin, and other points
in connection with it, I shall again revert to this highly interesting
paper of Mr. Wynne’s.
In the Deccan, half-way between Bombay and Nagpur, there is a very
remarkable salt lake. It is a circular hollow, about one mile across,
and from 300 to 400 feet deep, having at the bottom a shallow lake of
salt water without any outlet. This hollow, I must tell my reader, is
ascribed by scientific men to a volcanic explosion.
There are so many lakes of salt, which are completely isolated and
so many miles from the sea, that it is next to impossible to account
for their existence if we do not ascribe them to volcanic action. If
they are situated in low-lying districts, we may justly presume that
at one time the sea must have been present, or that the deposition
must have resulted from occasional, or tidal, overflow of salt water;
but when they are many miles from the coast, and many feet above or
below the sea-level, then they may be due to volcanic agency; and we
shall find further on several other salt lakes of variable depths
or altitudes which would seem to corroborate this hypothesis. The
sea is undoubtedly a most formidable agent in the disintegration of
land, and often destroys whole tracts, forcing its resistless waves
into the interior of continents, and then, owing to some unexplained
cause, retiring to its original boundary. This may take centuries
to complete, for revolutions effected by nature are not accomplished
speedily, unless there is some sudden spasmodic upheaving, arising from
earthquakes or storms. In 1282, the isthmus uniting Friesland with the
north of Holland was totally destroyed by violent storms. In our own
country a similar phenomenon occurred in the year 1475, when a large
tongue of land at the mouth of the Humber was entirely broken up and
carried away by the sea. In 1510 an irruption of the Baltic formed the
Frische-Haff, an opening 6000 feet broad, and from twelve to fifteen
fathoms in depth. The eastern coast of England is continually receding,
owing to the encroachment of the sea. The rate of encroachment of the
sea at Owthorne, in Yorkshire, is reckoned at four yards in every year,
and several villages have been swallowed up by the ocean; and in like
manner the cliffs of Norfolk and Suffolk are suffering a continual
decay.
Though the sea is so destructive an element, it is also an agent in the
reproduction of land. The rocks and sand washed away from one place
are conveyed by tides and currents far into the sea, and are deposited
in strata, and then, in course of time, form shoals and banks, which
subsequently become promontories and islands. Alluvial land has thus
been formed, and in a similar way have many of the stratified rocks
been deposited; and as animals and plants have been carried away and
imbedded in the deposits of rivers, or floods, so at some future
period, though countless ages may elapse during the process, will such
animals and plants be discovered deposited in these newer strata, just
as we find organic remains in the older rocks. The gradual deposition
of strata has been the work of an incalculable period of time, but the
process may be traced every day in the sections of marine estuaries
and lakes. Owing to this continual receding of the land in one part,
and elevation of land in another, there is an incessant change, from
which, though occupying many ages, and proceeding so slowly that it
would be unobservable were it not for accurate investigation, we may
easily conjecture that what is now land may at one time have been the
bed of the ocean, and where the sea now sweeps with overpowering fury,
there may once have been meadows and forests. The salt lakes, if not
originating from volcanic force, no doubt are the remains of the great
ocean, which, when it receded, left here and there, in what once were
luxuriant valleys, large reservoirs, indicating that in bygone ages it
had covered the land.
In Germany, Spain, Italy, Hungary, and Poland, there are extensive
mines of rock-salt, and also in various other parts of Europe.[36]
There are also large mountains wholly composed of this fossil salt,
two of which are in those provinces of Russia known as Astrakhan and
Orenburg; and in the Crimea salt is said to be daily accumulating in
the inland lakes. In Asiatic Russia there are extensive beds of salt,
near Lake Indur, in lat. 48° 30´, long. 69°. The Caspian Sea, called
by the Turks “Cozgoun Denghizi,” “the sea of crows and cormorants,” is
“a great salt-water lake,” according to Dr. William Smith, though Dr.
Lemprière says that “its waters are sweet.”
The most interesting salt-mine is that of Wieliczka, near Cracow, in
Galicia; it has been celebrated for centuries, and has been worked
for the last six hundred years. This wonderful mine is excavated in a
ridge of hills at the northern extremity of the chain which joins the
Carpathian mountains. When the stranger reaches the mine there bursts
upon his view a little world, the beauty of which is scarcely to be
imagined. He beholds a spacious plain containing a kind of subterranean
city, with houses, carriages, and roads, all scooped out of one vast
rock of salt, as bright and glittering as crystal, while the blaze of
the lights continually burning for the general use is reflected from
the dazzling columns which support the lofty arched vaults of the mine,
which are beautifully tinged with all the colours of the rainbow, and
sparkle with the lustre of precious stones, affording a more splendid
and fairy-like aspect than anything above ground can possibly exhibit.
In various parts of this spacious plain stand the huts of the miners
and their families, some single, and others in clusters, like villages.
They have very little communication with the world above them, and many
hundreds of persons are born and pass the whole of their lives here.
Through the midst of this plain lies a road which is always filled with
carriages laden with masses of salt from the furthest part of the mine.
The drivers are generally singing, and the salt looks like a load of
gems. A great number of horses are kept in the mine, and, when once let
down, never see daylight again.
Such is the marvellous salt-mine of Wieliczka, which is more renowned
on account of its magnitude, its age, and the weird and almost
supernatural aspect it presents to the visitor, than any other. Those
subterranean palaces, with their magnificent appurtenances, their
fantastic occupants, and other dreams of the imaginative, are not
more strange or astonishing to the fascinated reader of romance than
this extraordinary, glistening, cavernous, mineral city, with its
numerous lamps, its crystallised walls, its roads, and the plaintive
songs of the drivers as they drive their horses through its sunless
thoroughfares, presents to the eyes of the surprised traveller.
There are valuable mines of salt in France, and in Greece, near
Missolonghi, but these have no special points of interest connected
with them.
In Abyssinia there are extensive and inexhaustible beds of salt, which
is used in quite a different way from what it is in other countries,
for little bars of it are circulated in place of small coin; but it is
only when it reaches the Amhara and Galla districts that it becomes
valuable.[37]
In other parts of the African continent there are large mountains of
rock-salt, and those of Tunis and Algiers are especially notable.
Salt is also to be found in Asia, in large mountains, in marshes,
and in lakes, to some of which I have already alluded. In the north
of Persia there is a large salt desert, and near Ispahan there are
quantities of rock-salt. The island of Ormuz, in the Persian Gulf,
almost consists of fossil salt; it is indeed so very plentiful that the
atmosphere is completely charged with it, so that the dwellings of the
inhabitants are encrusted with a tolerable thick layer, giving them a
peculiar glistening appearance; this phenomenon is owing to the small
particles of salt continually floating in the air and rising from the
ground, much in the same way as we see dew deposited on the top of a
garden wall or on a lawn after a hot summer’s day.
We learn from Herodotus that there was a salt lake in Phrygia, in Asia
Minor. “Having so said, and fulfilled his promise, Xerxes continued
his route onwards. After passing by a city of Phrygia, called Anaua,
and a lake out of which salt is produced, he came to Colossæ, a large
city of Phrygia.”[38] I have previously alluded to the Dead Sea and the
interesting phenomena which it presents; due south of it is the Valley
of Salt.
There are salt springs and springs from inflammable gas in China, in
long. 101° 29´, lat. 29°, near Thibet; and there is a large salt lake
possessing the strange name of Tsomoriri, many feet above the level
of the sea, in Western Thibet.[39] “The Chinese bore well through the
rocks, and prepare the salt by firing the gas of others, so that one
heats 300 kettles by gas-fire.” The celestials, with their habitual
aptitude and industry, have obtained this salt for many centuries, and
simply by this ingenious method.
As a fact illustrating the value of salt in Siberia, I may as well
mention that in our own country a ton of salt is sold for fifteen
shillings, whilst on the Yenesei river as much as fifteen pounds is
given for the same quantity. The Muscovite we thus see is as acutely
alive to the beneficent results of a free use of salt as a dietetic, as
we English, and it would seem as if he were more so.
In some countries remote from the sea, which are devoid of salt-mines,
and where the water is not impregnated with it, the inhabitants, aware
of its usefulness, have a method of extracting it from the ashes of
vegetables. This fact would certainly seem to indicate that salt has
been used by various nations, as if mankind had an intuitive knowledge
of the benefits arising from the use of salt, and that consequently, if
there were no lakes containing it, or mountains from which they could
procure it, they were determined to obtain it if even by artificial
means.
As an illustration of the presence of salt in places distant from the
sea, I need only refer to the Great Salt Lake of Utah, on the shores of
which stand the Mormon city. Long before the founder of the Latter Day
Saints thought of establishing a quasi-religious community, travellers
who had the temerity to wander over the wild prairies of the Oregon,
the home of the bison and the hunting-ground of the Indian, and who
explored the secrets of the then unknown land of the “Far West,” were
struck with amazement at the glistening aspect of the surface; for in
many places it was covered over with an impure kind of salt, apparently
a combination of _muriate and sulphate of soda_,[40] or more probably
an impure form of the _chloride of sodium_. On tasting the water which
had collected in numerous little pools of no more than a few inches
in depth, they found it so bitter and pungent that it acted on the
mucous membrane almost as powerfully as a corrosive poison. This large
tract of country was at that time teeming with life, for they daily
saw vast herds of bisons, and frequently came upon the hidden towns of
the prairie-dog; in fact, wherever they went, they either crossed the
path of these wild denizens of the plain, or else the sky was darkened
by innumerable flocks of birds. The district was wonderfully healthy,
and totally free from malaria or other causes generative of disease;
the Indians, too, were splendid specimens of humanity; they had not as
yet been tainted by too close a proximity with the so-called superior
civilisation of the white man, neither had they been so unfortunate
as to have fallen a prey to the vices and diseases which generally
accompany the humanising European.
On the pampas of La Plata, which is the treeless abode of the wild
horses of South America, there are several salt lakes, not many
miles distant from the river Quinto, and over these boundless wastes
thousands of wild cattle and horses gallop at pleasure, and afford an
inexhaustible stock of game for the lasso of the fearless and expert
Gaucho. Now it is a well-authenticated fact that those diseases which
are so destructive to the horses and cattle of Europe are almost
unknown in these regions. I do not mean to assert that these salt lakes
of La Plata account for the exemption which this district enjoys from
equine diseases; but there is no doubt that the exhalations from them
purify the atmosphere, and that their influence extends for many miles
because of the open nature of the country. As a natural result, the
whole region is constantly kept in a healthy state; for air, charged
with the chloride of sodium, must of necessity act as a preventive to
everything inimical to health, and pure air we know (though how few
really know what that blessing is) is of a paramount importance in
the rearing of cattle. The foot-and-mouth disease, comparatively, has
never played such havoc as it does in Europe, and pneumonia, which is
almost intractable to treatment in this part of the world, and which
is frequently fatal when it is complicated with inflammation of the
pleura, hardly ever appears in these parts, where stables and farms are
not far off from being rudimentary in construction, and would appear
to an English farmer, accustomed to the cosy-looking farmsteads of his
own country, very ill-calculated for successful farming, and not at
all adapted for bringing his cattle and horses to perfection; yet it
is just the reverse, for there is no other part of South America so
well fitted for the breeding of cattle, and there is no other locality,
whether in the Old or New Worlds, so completely free from disease as
the open pampas of La Plata.