The idea which had transformed him was perhaps the conception of a lunatic. But it was still an idea, and offered a chance. Again Kirby peered down his rifle. But he no longer aimed at Naida. As Quetzalcoatl lifted white fangs, Kirby aimed deliberately at him, and turned loose his fire. With the first shot, the Serpent lurched back from the cage, snapped his jaws, and closed evil, black eyes. From one lidded socket squirted dark blood. As a second and third shot crashed into the cavernous fanged mouth, and others ripped into the flat skull, Quetzalcoatl seemed dazed. His head wavered back and forth and his hiss filled the night, but he did nothing. But all at once Kirby felt that he was _going_ to do something in a second, and a great calm came upon him. He quickly jammed home a fresh clip of shells. "Nini! Ivana! Fire at the Serpent. Give him everything you've got! Do you understand? Fire! He thinks that the ape-people have hurt him, and he will be after them in a second. If we have any luck, he will do to them what we never could have done, and maybe destroy himself at the same time! Me, I'm going down there and get Naida now!" CHAPTER XIII No sooner did Kirby see comprehension in the girls' faces than he swung around and let go of his perch. As he crashed, caught the next limb below him, and let go to crash to another, he had all he could do to suppress a yelp of joy. For all at once every voice in the ape congregation was raised in howls and screams of devastated terror. He did not care how he got down from the tree. Seconds and half seconds were what counted. From the last limb above the ground he swung into space, and a split second later staggered to his feet, clutched his rifle, and started for the clearing. His lungs seemed collapsed and both ankles shattered. He did not care. Not when the ape screams were growing louder with every step he took. Not when he heard Nini and Ivana pouring down from their tree a continuation of the scorching fire he had started. Panting, his breath only half regained, but steeled to make the fight of his life, he tore from the jungle into the clearing just in time to see a twisting, pain-convulsed seventy-foot coil of white muscle lash up and strike Naida's cage a blow which knocked it like a ball in the air. Naida screamed and hung to the bars. But she was all right. It was not against her that Quetzalcoatl was venting his wrath: the blow had been blind accident. As Kirby stood at the clearing's edge, he knew to a certainty that Quetzalcoatl's reaction to sudden pain had been all he had dared hope.