"Those first men didn't just guess that such power existed--they _knew_ because the beast had taught them and they tried to imitate it--the mystagogues and tyrants through the ages, with voices, with tomtoms and bull-roarers and trumpets. What makes the memory of that voice so hard to live with is just knowing that what it called to is a part of man--isn't that it?" Thwaite didn't answer. He had taken the heavy rifle across his knees and was methodically testing the movement of the well-oiled breech mechanism. Dalton stood up wearily and picked up his suitcase. "I'll check into the hotel. Suppose we talk this over some more in the morning. Maybe things'll look different by daylight." But in the morning Thwaite was gone--upriver with a hired boatman, said the natives. The note he had left said only, _Sorry. But it's no use talking about humanity--this is personal._ Dalton crushed the note angrily, muttering under his breath, "The fool! Didn't he realize I'd go with him?" He hurled the crumpled paper aside and stalked out to look for a guide. * * * * * They chugged slowly westward up the forest-walled river, an obscure tributary that flowed somewhere into the Xingu. After four days, they had hopes of being close on the others' track. The brown-faced guide, Joao, who held the tiller now, was a magician. He had conjured up an ancient outboard motor for the scow-like boat Dalton had bought from a fisherman. The sun was setting murkily and the sluggish swell of the water ahead was the color of witch's blood. Under its opaque surface _a mae dagua_, the Mother of Water, ruled over creatures slimy and razor-toothed. In the blackness beneath the great trees, where it was dark even at noon, other beings had their kingdom. Out of the forest came the crying grunting hooting voices of its life that woke at nightfall, fiercer and more feverish than that of the daytime. To the man from the north there seemed something indecent in the fertile febrile swarming of life here. Compared to a temperate woodland the _mato_ was like a metropolis against a sleepy village. "What's that?" Dalton demanded sharply as a particularly hideous squawk floated across the water. "_Nao e nada. A bicharia agitase._" Joao shrugged. "The menagerie agitates itself." His manner indicated that some _bichinho_ beneath notice had made the noise. But moments later the little brown man became rigid. He half rose to his feet in the boat's stern, then stooped and shut off the popping motor. In the relative silence the other heard what he had--far off and indistinct, muttering deep in the black _mato_, a voice that croaked of ravenous hunger in accents abominably known to him. "_Currupira_," said Joao tensely. "_Currupira sai a cacada da noite._" He watched the foreigner with eyes that gleamed in the fading light like polished onyx. "_Avante!_" snapped Dalton. "See if it comes closer to the river this time."