"You see, we have not so much time as nature," said Professor Gurlone. "These beasts cannot be enlarged too rapidly, or they would die. They must be protected from the direct rays of the radium, which is refined. In the ore, the action is more gradual and gentle, since it is less concentrated. But the metal itself would burn the vital organs out of these creatures, cause them to be struck blind, shrivel them up inside and kill them in a few minutes in the quantity we have. We expose them bit by bit, allowing more and more time as they begin to grow immune to the rays. Here, you see, are smaller creatures which have grown some eight or ten times beyond normal size." All the animals seemed the worse for wear. Maget, his brain reeling, yet was beginning to grasp what radium did to one. It was not gold that you could pick up and carry away. "If a man touched that radium," he asked, "what would happen to him?" "Just what I said would happen to the animals if we did not give it to them gradually," said Gurlone, with a wave of his hand. "It would kill him, strike him down as though by invisible poison gas. His heart and lungs would cease to function, pernicious anemia would set in, as the red corpuscles in his blood perished by millions. He would be struck blind, fall down and die in agony." To Maget came the picture of the unfortunate Juan. As though answering his unasked question, Professor Gurlone went on. "We had a peon coming up with us," he said. "His name was Juan. He stole my sample-case, which contained an ounce of radium chloride, and ran off with it. If he opens it, it will kill him in just that way." * * * * * Maget shivered. "But--but didn't it hurt you to carry it?" he asked. "No. For it was incased in a lead container some two inches in thickness, and the rays cannot penetrate such a depth of lead. They are trapped in the metal." "Father, father, you're wasting time," broke in Kenneth Gurlone, shaking his yellow head. "We must act at once. The peons are almost mad with fear. Even Espinosa cannot quiet them. And every moment is precious, for the monsters may break forth." But Maget was looking nervously about for Durkin. Where was he? Durkin had his mind on the treasure, and-- As they turned toward the door, the professor saying. "The rays from the ore, which is not so concentrated as the purified metal, do not kill--" Durkin suddenly appeared. He carried his rifle at his hip, and he limped and cursed angrily. "Come across," shouted Durkin. "Give me the key to that stone house. Snap into it, and no argument." "The key--to the stone bank?" repeated old Gurlone. "Yes. I'll give you five counts to throw it over--then I'll shoot you and take it," snarled Durkin savagely. "I want that treasure, whatever it is, and I'll have it. One ... two ... three...." The tramp sent a shot over their heads as a warning. "Hey, Bill, easy, easy," pleaded Maget. "That stuff is radium. It'll ruin you, boy!"