The world, with the enemy now discovered, was immediately less apprehensive. White, and gray-skinned people down there--they seemed neither very numerous nor very menacing. The public rang with boastful predictions of what would happen when our planes were ready to attack. Not a very numerous enemy, nor very menacing! Not menacing? A gray-white shape was observed on the night of October 15, flying at the Zero-height near the Australian Continental shelf. It was vaguely described. An aëro--very flat and narrow--wingless--several hundred feet long by twenty feet wide. On October 17 a strange disease was reported from Southeast Australia. People were stricken by it over a widely separated area. But all of them lived at or near the Zero-height, at the edge of the Southeast shelf, the border of the Lowlands. Strange disease indeed! The reports came to Dr. Plantet. A number of the suffering victims were brought by fast airline to Washington. Dr. Plantet, with a group of leading medical men, met in Washington to study the disease. Whether contagious, or infectious, or both, they could not say. A germ disease undoubtedly. Swiftly progressing. A day of darkening fingernails. Fingers and toes turning numb and black. The whites of the eyes turning dark. A lassitude. A gruesome coma with the victim screaming as in a nightmare. Then a calm, trancelike catalepsy, followed by death. Dr. Plantet came back to Polly. He was grim. He slumped in his chair. “We don’t know what it is, Polly. Nothing we have ever had to deal with before.” She had never seen him so solemn, so drab. He lifted his white tired face; his eyes were burning from lack of sleep. “It’s from that thing they saw, Polly--that gray-white aëro. Nothing much has been said about it publicly, and I hope to Heaven they won’t yet for awhile. But that’s where this disease came from--we’re sure of that.” He sat up with a slight return of his old energy. “They’ve got to annihilate this enemy! At once--it’s got to be done. They’ve been saying: ‘We’ve got them helpless, down there in the Lowlands. They can’t harm us.’ Harm us? This is no warfare of the kind we’ve ever known! Inhuman, unreasoning--what sort of men must these gray people be! No attack--nothing military--no open warfare--nothing! Just spreading a disease. There are women and children among those victims, Polly--more women than men. It will wipe us out--it will mean the end of the world for us all unless we can check it!” CHAPTER XXII. REFUGEES OF THE LOWLANDS. Tad and I struggled upward into the tunnel-passage. The fact that with Arturo and Nereid, and some two thousand of the Middge people, we at last reached the surface I have already made evident. I need not detail those weary, despairing days and weeks in the darkness. It may have been a march of several hundred miles. I do not know. I would have said it consumed a year, rather than those weeks.