They started up a narrow declivity along the canon face. The Chemist led the way; the Very Young Man, with Aura just in front of him, was last. They had been walking only a moment when the Chemist called back over his shoulder. "It's getting very narrow. We'd better stop here and take the drug." The Chemist had reached a rocky shelf--a ledge some twenty feet square that jutted out from the canon wall. They gathered upon it, and took enough of the diminishing drug to stop their growth. Then the Chemist again started forward; but, very soon after, a cry of alarm from Aura stopped him. The party turned in confusion and crowded back. Aura, pale and trembling, was standing on the very brink of the ledge looking down. The Very Young Man had disappeared. The Big Business Man ran to the brink. "Did he fall? Where is he? I don't see him." They gathered in confusion about the girl. "No," she said. "He--just a moment ago he was here." "He couldn't have fallen," the Doctor exclaimed. "It isn't far down there--we'd see him." The truth suddenly dawned on the Doctor. "Don't move!" he commanded sharply. "Don't any of you move! Don't take a step!" Uncomprehending, they stood motionless. The Doctor's gaze was at the rocky floor under his feet. "It's size," he added vehemently. "Don't you understand? He's taken too much of the diminishing drug." An exclamation from Oteo made them all move towards him, in spite of the Doctor's command. There, close by Oteo's feet, they saw the tiny figure of the Very Young Man, already no more than an inch in height, and rapidly growing smaller. The Doctor bent down, and the little figure waved its arms in terror. "Don't get smaller," called the Doctor. But even as he said it, he realized it was a futile command. The Very Young Man answered, in a voice so minute it seemed coming from an infinite distance. "I can't stop! I haven't any of the other drug!" They all remembered then. Targo had stolen the Very Young Man's vial of the enlarging drug. It had never been replaced. Instead the Very Young Man had been borrowing from the others as he went along. The Big Business Man was seized with sudden panic. "He'll get lost. We must get smaller with him." He turned sidewise, and stumbling over a rock almost crushed the Very Young Man with the step he took to recover his balance. Aura, with a cry, pushed several of the others back; Oteo and Eena, frightened, started down the declivity. "We must get smaller!" the Big Business Man reiterated. The panic was growing among them all. Above their excited cries the Doctor's voice rose. "Stand still--all of you. If we move--even a few steps--we can never get small and hope to find him." The Doctor--himself too confused to know whether he should take the diminishing drug at once or not--was bending over the ground. And as he watched, fascinated, the Very Young Man's figure dwindled beyond the vanishing point and was gone! CHAPTER XXXIX A MODERN DINOSAUR