Between the north-eastern borders of the Transvaal and the coast lies the
Portuguese colony Mozambique. Its frontier railway station, Ressario Garcia,
is near that of the Transvaal, viz., Komati poort, which is 53 miles from
Delagoa Bay. A low-lying country extends from the coast about 100 to 200
miles inland, and is tropical. Except some elevated spots, the whole of it
is almost uninhabitable in summer by whites on account of malaria. During
some specially bad seasons natives even succumb to that malady. The only
comparatively safe months are from June to November. Marshy localities, and
wherever there is shaded rank vegetation in low-lying parts, are dangerous
all the year round; in such places the water is deadly at all times unless
first boiled.
This malarial poison is distinct from that which produces yellow fever in
America, and is so far unlike it as it is not contagious. The theory is that
the poison is produced below the surface by decaying vegetable matter in low
and dank parts during the more inactive but still warm and sunny winter
season and during the hot months preceding the summer rainfall. Upon the
first rains the malarial poison escapes through the then softened crust in
the shape of vapoury miasms. This happens during the night, after the
surface of the earth has been cooled off. Those miasms are dissipated or
neutralised by the action of the sun. The dewy grass retains the poison
until it is thoroughly dried to the root. All surface water is liable to
that poisonous impregnation. Malarial manifestations occur all over South
Africa, but in progressive degrees of virulence with the advance to warmer
latitudes, and with the descent from the high table-lands to the coast
levels. On the Transvaal high veldt, for example, a mild form is developed
which, in midsummer, to a small extent, affects and kills sheep. It is
called blaauwtong, and does not affect horses. Descending further, this
danger to sheep increases and begins earlier. Below 5,000 feet altitude in
the Transvaal the summer season is dangerous to sheep, and horses and mules
are subject to horse sickness; whilst lower still the same malaria attains
sufficient virulence to attack human beings, and becomes very deadly upon
levels nearing the coast. Komati poort, the frontier railway station already
mentioned, is dreaded as a still worse death-trap than even Delagoa Bay,
where it is very unsafe, say, from December to end of April. The season of
horse sickness terminates upon the appearance of the first sharp frost in
May. The safeguards for human beings consist in avoidance at night and early
morning of low-lying localities, or such elevated places even which are
subject to be invaded by miasmatic emanations produced on and wafted from
dangerous lower levels. Drink no unboiled water except that from deep wells
or rain-water; maintain careful and moderate diet, active habits, but
avoiding extreme exertions and excitements; a very sparing use of alcoholic
drinks, preferably taken with the regular meals, is admissible.
Donkeys, horned cattle, and goats are exempt from malarial risks.
For horses and mules no certain remedy appears as yet to be known. The best
research, on behalf of the Transvaal Government, by specially requisitioned
French bacteriologists, assisted by that famous microbe-hunter, Dr. Theiler
(Dr. Theiler is the Transvaal veterinary surgeon and chief of the Medical
Laboratory, Pretoria, a noted Swiss savant, who, with the aid of the said
French experts, discovered the rinderpest inoculation remedy), has failed to
find the bacillus of horse sickness. Barely five per cent, of the horses
attacked recover, and about ten per cent, of mules. These are then called
salted, and are immune from horse sickness; they can after that be safely
used in the worst localities, and are correspondingly more valuable. They
are, however, liable periodically to light after-attacks, when it is safer
to exempt them from work for a day, or for a few hours at least.
Some proprietors of mail coaches are in the habit of administering doses of
arsenic to their horses and mules, which are said to operate in lessening
the death rate and to favour the salting process.
As
safeguards for horses and mules, the following rules have been found to
minimise losses in dangerous tracts where the low clinging miasmatic vapours
are so deadly during the night and earlier parts of the morning. (During
rainfall there is hardly any danger, nor is there after a night's rain for
the day following):—
Do
not traverse low suspicious tracts during the hours between 9 p.m. and, say,
two hours after sunrise, lest poisonous vapours be encountered and inhaled
by man or horse.
Choose the most elevated spots for camping out at night. No grazing to be
allowed from 10 p.m. to about 10 or 11 a.m., unless it is raining. Dewy
grass is fatally poisoned; the heavy moist air close to the surface is also
suspected. Grazing is only safe after the soil and grass are dried of all
dewy moisture.
Avoid all water of at all a stagnant nature; rather let the animals remain
thirsty.
If
the animals have been fed with dry fodder during the night, let the first
morning stage be moderate and not exhausting. With empty stomachs the task
might be somewhat increased, but even then it should be less than any other
succeeding stage. When the first symptoms of sickness are noticed they may
pass over if the animal is at once freed from work and allowed to rest, or
is at most led when marching. Among the most dangerous places for horse
sickness and for fever to human beings are the luxurious dongas, ravines,
and valleys which abound along the long stretches of mountains and broken
country immediately below the high plateaux.
The passes leading up to the high veldt are few in number, and so
precipitous as to be almost impracticable for vehicles. Of late years those
roads have been allowed to fall into disrepair, in order, it may be
supposed, to check wagon traffic and to promote that by railway; apart from
the railway, communication with Delagoa Bay would now be impossible. What
with the fever climate in summer, and the formidable mountain barriers, the
Transvaal high veldt is well protected from aggression from the direction of
Delagoa Bay. A few thousand men distributed at the few mountain passes,
blocking the tunnel at one of these (at Waterval Boven), and breaking up
some few bridges, would effectually arrest the progress of any invading
force.
