for gravitation-paralysis." Captain Walls, himself an old-time space-man, was first of the group to appreciate the significance of the statement. The captain gasped. "A preventative for gravitation-paralysis? Kenniston, are you sure?" Kenniston nodded gravely. "Yes. Ricky had been working on the problem a long time, back in the Institute of Planetary Medicine. He thought he'd found a way to prevent gravitation-paralysis, the most awful scourge of all the outer System, the thing that's doomed so many space-men. But his formula required rare elements found only in the outer planets. "Ricky and I," he continued, "went out there and secured those elements. He made up this formula, and tried it on a gravitation-paralysis case—a space-man who's lain paralyzed for years. The formula was designed to strengthen the human nervous system against the shock of varying gravitations, to re-establish an already damaged nerve-web. And it worked." Kenniston's voice was husky as he concluded. "It worked, and that living log became a man again. The formula was a success. Ricky and I started back for Earth, where he intended to announce the discovery and arrange for its manufacture on a big scale. But, on the way back, Dark's pirates captured us." Kenniston flung out his hand in a tortured gesture. "That's why I went to any lengths to save Ricky's life! It's because Ricky is the only person who knows the intricate formula of this serum. If he were to die, the secret of the cure would die with him. And that would mean that thousands on thousands more of space-men would be stricken into living death by gravitation-paralysis in the future, just as so many thousands of old friends and shipmates of mine have been stricken in the past!" Captain Walls was the first to speak. Quietly, the plump master of the Sunsprite extended his hand. "Kenniston, will you shake hands with me? And will you forgive me for everything? You did absolutely right. I'm an old space-man and I know what gravitation-paralysis is." Gloria's dark eyes were glimmering with tears. "If we'd only known," she murmured to Kenniston. "No one could blame you for sacrificing a lot of worthless idlers like us, for a thing like this." "But you're going to be all right—all of you," Kenniston assured her. "John Dark will make you pay a big ransom,