A call from Pedro forestalled any answer. The trio struggled along to the spot where the guides waited at the butt of a slanting tree trunk spanning the gulf. As they reached it Pedro walked carefully up the trunk, carrying a long slender sapling, which he lowered and fixed in the bottom of the stream. Then, steadying himself with the upper end of this pole, he continued his journey to the other side, where he flipped the sapling back to Lourenço. One by one the others crossed, slipping, almost losing balance, but managing to evade a fall. Tim, walking the precarious bridge and looking down, saw that the surface of the water was dotted with the heads of venomous snakes. "Are you following your trail of yesterday?" demanded McKay. "No, Capitao. Yesterday we circled. To-day we go as nearly straight as possible." "And you can find the appointed place by this new route?" The captain's tone was dubious. "Certainly. Else I should go the other way. Come." Up another bank they toiled, and on through rugged country which seemed momentarily to become higher and harder to traverse. In the minds of the Americans grew suspicion that, for the first time, the Brazilians were bluffing; it seemed impossible for any man to keep his sense of direction in such a maze. But they said no word and followed on. At length the leader paused and sent the long call of the mutum floating through the trees. No answer came. After a moment the line moved on, each man peering ahead with sharper gaze, each holding a little tighter. To the Americans, at least, the thought of possible ambush loomed large. Four man-eating savages, hidden in this labyrinthine tangle and armed with arrows whose slightest scratch meant death, could strike down every man of this expedition without even a wound in return; for of what avail were high-power guns, automatic pistols, and machetes against invisible enemies? Yet there was assurance in Lourenço's confident air, and reassurance in the thought that these tribemen would be unlikely to assail a band avowedly on its way to visit their chief. Besides--Knowlton smiled grimly--even if the Mayorunas hungered for human flesh it would be more economical of labor to let the meat travel to the slaughterhouse on its own legs than to kill it here and carry it home. Again the mutum whistle drifted away. Again no answer came. For a short distance farther the file continued its march. Then, in a small opening where the uptorn roots of a tree rose like a wall at one side, it halted. "The place of meeting," Pedro said. All peered around. None saw anything but the upstanding roots, the forest jumble, the misty serpentine lianas. None heard any sound but their own hoarse breathing, the solemn drip of water, the insect hum, and the occasional melancholy notes of birds. The place seemed bare of life. Yet upon McKay came again that feeling of being watched.