ifficulty lay
not merely in the badness of the track through ground almost impassable
during and after the rains, but also in the prevalence of the
tsetse-fly, whose bite is fatal to cattle. It has enabled travellers to
cross in a few hours one of the most unhealthy regions in the world,
most of which is infested by fevers in and after the wet season, and the
lower parts of which are so malarious that few who spend three nights in
them, even in the dry season, escape an attack. The banks of the rivers
and other damper spots will continue to breed this curse of maritime
Africa, although things will doubtless improve when the country grows
more settled, and the marshes have been drained, and the long grass has
been eaten down by cattle; for when the tsetse-fly has ceased to be
dangerous cattle may come in. It appears that the fly kills cattle not
by anything poisonous in its bite, but because it communicates to them a
minute parasite which lives in the blood of some kinds of game, and
which is more pernicious to cattle than it is to the game. Accordingly,
when the game vanishes, the fly either vanishes also or becomes
comparatively harmless. Already places once infested by it have by the
disappearance of the game become available for ranching. Recent
researches seem to have shown that malarial fevers in man are also due
to an animal parasite: and this discovery is thought to damp the hope,
which I remember to have heard Mr. Darwin express, that the
fever-stricken regions of the tropics might become safe by ascertaining
what the fever microbe is and securing men against it by inoculation.
Those, however, who hold that this parasite is carried into the blood of
man by a mosquito seem to entertain some hope that drainage may in some
places almost expunge the mosquito. The railway was made entirely by
native labour gathered from the surrounding regions, and the contractors
told me they had less difficulty with the Kafirs than they expected. It
paid, however, a heavy toll in European life. Not one of the engineers
and foremen escaped fever, and many died. The risk for those employed on
the line is of course now much slighter, because the worst spots are
known and there are now houses to sleep in.

Shortly after leaving Chimoyo the train ran through a swarm of locusts
miles long. It was a beautiful sight. The creatures flash like red
snowflakes in the sun; the air glitters with their gauzy wings. But it
is also terrible. An ear