UP THE PARAGUAY 41 



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 labora- 

 tory 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 pic- 

 turesque 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 pi- 

 ranha 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 Para- 

 guay the piranha do not seem to go in regular schools, but 

 they swarm in all the waters and attain a length of eigh- 

 teen 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 them- 

 selves. 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 ex- 



