also we are not as yet able to
fathom, these insects are for the most part strictly limited by
geographical and other considerations. The war against what Sir Harry
Johnston calls the really material devil, the devil of evil wild
nature in the tropics, has been waged with marked success only during
the last two decades. The men, in the United States, in England,
France, Germany, Italy--the men like Doctor Cruz in Rio Janeiro and
Doctor Vital Brazil in Sao Paulo--who work experimentally within and
without the laboratory in their warfare against the disease and death
bearing insects and microbes, are the true leaders in the fight to
make the tropics the home of civilized man.

Late on the evening of the second day of our trip, just before
midnight, we reached Concepcion. On this day, when we stopped for wood
or to get provisions--at picturesque places, where the women from
rough mud and thatched cabins were washing clothes in the river, or
where ragged horsemen stood gazing at us from the bank, or where dark,
well-dressed ranchmen stood in front of red-roofed houses--we caught
many fish. They belonged to one of the most formidable genera of fish
in the world, the piranha or cannibal fish, the fish that eats men
when it can get the chance. Farther north there are species of small
piranha that go in schools. At this point on the Paraguay the piranha
do not seem to go in regular schools, but they swarm in all the waters
and attain a length of eighteen inches or over. They are the most
ferocious fish in the world. Even the most formidable fish, the sharks
or the barracudas, usually attack things smaller than themselves. But
the piranhas habitually attack things much larger than themselves.
They will snap a finger off a hand incautiously trailed in the water;
they mutilate swimmers--in every river town in Paraguay there are men
who have been thus mutilated; they will rend and devour alive any
wounded man or beast; for blood in the water excites them to madness.
They will tear wounded wild fowl to pieces; and bite off the tails of
big fish as they grow exhausted when fighting after being hooked.
Miller, before I reached Asuncion, had been badly bitten by one. Those
that we caught sometimes bit through the hooks, or the double strands
of copper wire that served as leaders, and got away. Those that we
hauled on deck lived for many minutes. Most predatory fish are long
and slim, like the alligator-gar and pickerel. But the piranha