The line rushed overboard and cut the water with a hissing sound; a moment later the keg followed with a splash and began a wild rush into the river. It was a [Illustration: A huge silvery form ... leaped out of the water, rolled and wallowed convulsively, and sank from sight.] great sight to see the half-submerged buoy tearing a wide path through the muddy water, towed by the terrified monster deep below. “The _curare_!” Don Marco shouted; but the men had already untied the dugout canoe that trailed behind the batalao. The captain, David and two of the sailors jumped into it and they were off after the fleeing keg. “He can’t keep it up very long,” Don Marco panted as they dug deep their paddles and sped along. “A few kilometers at most and the drag will tire him out. He must be enormous--look how the keg is travelling. If the line should break he will be lost.” After running downstream several hundred yards the float came to a stop. “It snapped, or the harpoon did not hold. He’s gone,” were the first thoughts that came to the pursuers. But a few minutes later it moved again, this time heading upstream. That was fortunate for the men but unfortunate for the fish, for now it had to fight not only the current but pull the hampering weight against the stream also. And it was coming straight toward the canoe. Soon it was abreast, so the paddlers turned the craft and now had no difficulty in keeping up with it. Bit by bit the fish weakened and after half an hour the keg stood still. “Now we must get it quickly, before it can rest,” the captain called. When they reached the float he leaned over, caught the line with his hands and began to pull it in, not hurriedly, but with an even, steady movement. This, however, gave new life to the fish. It dashed away, downstream, but the man retained possession of the cord and the canoe tore through the water at great speed, her nose ploughing so deeply that it was all but submerged. The men dropped their paddles and began to bail out the water that poured in in a steady stream; but soon it became apparent that their efforts could not stem the flood that was rising about their feet. If the fish did not slacken its pace soon they would have to release the line or the canoe would be swamped. But the great pirarucú was rapidly exhausting the last vestige of its strength in pulling the dugout. It was gradually coming nearer the surface; and then a huge, silvery form leaped out of the water, rolled and wallowed convulsively, and sank from sight. Don Marco rapidly took in the line and in a moment they had reached the spot where the last ripples were dying in a widening circle; soon the prize had been brought up from the muddy depths and wallowed helplessly beside the boat. What a beauty it was! And what a monster! A line was made fast just in back of the fins and they towed it back to the batalao, where it was hoisted aboard.