comparison.... You don't believe. It's hard. But you see that some of us, oldest in point of exile, are sliding back into bestiality. And you saw us drive away, as our custom is, a man who had definitely become a beast."

"That thing was a man?" prompted Parr, his spine chilling.

"It had been a man. As you wander here and there, you'll come upon queer sights—sickening ones."

Parr squinted at the huts, around the doors of which lounged the other men. "That looks like a permanent community, Sadau."

"It is, but the population's floating. I came here three months ago—Earth months—and the place was operating under the rules I outlined. Latest comer, necessarily the highest-grade human being, to be chief; those who degenerate beyond a certain point to be driven out; the rest to live peaceably together, helping each other."

Parr only half heard him. "Evolution turned backward—it can't be true. It's against nature."

"Martians war against nature," replied Sadau pithily. "Mars is a dead world, and its people are devils. They'd be the logical explorers to find a place where such things can be, and to make use of it. Don't believe me if you don't want to. Time and life here will convince you."

In the days that followed—the asteroid turned once in approximately twenty-two hours—Parr was driven to belief. Perhaps the slowness of the idea's dawning kept him from some form of insanity.

Every man of the little group that called him chief was on the way to be a man no more. There were stooped backs among them, a forward hang to arms, a sprouting of coarse, lank hair. Foreheads fell away, noses flattened coarsely, eyes grew small and shifty. Sadau informed Parr that such evidences of degeneration meant a residence of a year or so on the exile asteroid.

"We'll be driving one or two of them away pretty soon," he observed.

"What then?" asked Parr. "What happens to the ones that are driven out?"

"Sometimes we notice them, peering through the brush, but mostly they haul out by themselves a little way from here—shaggy brutes, like our earliest fathers. There are lower types still. They stay completely clear of us."

Parr asked the question that had haunted him since his first hour of exile: "Sadau, do you see any change in me?"

Sadau smiled and shook his head. "You won't alter in the least for a month."

That was reasonable. Man, Parr remembered, has been pretty much the same for the past ten thousand years. If a year brought out the beast in the afflicted exiles, then that year must count for a good hundred thousand years turned backward. Five years would be five hundred thousand of reverse evolution—in that time, one would be reduced to something definitely animal. Beyond that, one would drop into the category of tailed monkeys, of rodent crawlers—reptiles next, and then—

"I'll kill myself first," he thought, but even as he made the promise he knew he would not. Cowards took the suicide way out, the final yielding to unjust, cruel mastery by the Martians. Parr stiffened his shoulders, that had grown tanned and vigorous in the healthy air. He spoke grimly to Sadau:

"I don't accept all this yet. It's happened to others, but not to me so far. There's a way of stopping this, and paying off those Martian swine. If it can be done—"

"I'm with you, Chief!" cried Sadau, and they shook hands.

Heartened, he made inquiries. The Martian space-patroller came every month or so, to drop a new exile. It always landed on the plain where Parr had first set foot to the asteroid. That gave him an idea, and he held conference in the early evening, with Sadau, Shanklin, and one or two others of the higher grade.

"We could capture that craft," urged Parr. "There's only a skipper and three Martians—"

"Yes, with pistols and ray throwers," objected Shanklin. "Too big a risk."

"What's the alternative?" demanded Sadau. "You want to stay here and turn monkey, Shanklin? Chief," he added to Parr, "I said once that I was on your side. I'll follow wherever you lead."

"Me, too," threw in Jeffords, a sturdy man of middle age who had been sentenced for killing a Martian in a brawl.

"And me," wound up Haldocott, a blond youth whose skin was burned darker than his hair and downy beard. "We four can pull it off without Shanklin."

But Shanklin agreed, with something like good humor, to stand by the vote of the majority. The others of the community assented readily, for they were used to acting at the will of their wiser companions. And at the next arrival of the Martian patroller—an observer, posted by Parr in a treetop, reported its coming whole hours away—they made a quick disposal of forces around the rocket-scorched plain that did duty for a landing field. Parr consulted for a last moment with Sadau, Shanklin, Jeffords and Haldocott.

"We'll lead rushes from different directions," he said. "As the hatchway comes open, the patroller will stall for the moment—can't take off until it's airtight everywhere. I'll give a yell for signal. Then everybody charge. Jam the tubes by smacking the soft metal collars at the nozzles—we can straighten them back when the ship's ours. Out to your places now."

"The first one at the hatch will probably be shot or rayed," grumbled Shanklin.

"I'll be first there," Parr promised him. "Who wants to live forever, anyway? Posts, everybody. Here she comes in."

Tense, quick-breathing moments thereafter as the craft descended and lodged. Then the hatchway opened. Parr, crouching in a clump of bushes with two followers, raised his voice in a battle yell, and rushed.

A figure had come forward to the open hatch, slender and topped with tawny curls. It paused and shrank back at the sudden apparition of Parr and his men leaping forward. Tentacles swarmed out, trying to push or pull the figure aside so as to close the hatch again. That took more seconds—then Parr had crossed the intervening space. Without even looking at the newcoming exile who had so providentially forestalled the closing of the hatch, he clutched a shoulder and heaved mightily. The Martian whose tentacles had reached from within came floundering out, dragged along—it was the skipper whose ironic acquaintance Parr had made in his own voyage out, all dressed in that loose-plate armor. Parr wrenched a pistol from a tentacle. Yelling again, he fired through the open hatchway. Two space-hands ducked out of sight.

"We've won!" yelled Parr, and for a moment he thought they had. But not all his followers had charged with his own bold immediacy.

Sadau on one side of the ship, Jeffords and Haldocott at the other, had run in close and were walloping manfully at the nozzles of the rocket tubes. The outer metal yielded under the blows, threatening to clog the throats of the blasts. Only at the rear was there no attack—Shanklin, and with him three or four of the lesser men, had hung back. The few moments' delay there was enough to make all the difference.

Thinking and acting wisely, even without a leader, the Martian space-hands met the emergency. They had withdrawn from the open hatchway, but could reach the mechanism that closed it. Parr was too late to jump in after them. Then one of them fired the undamaged rear tubes.

Swish! Whang! The ship took off so abruptly that Parr barely dodged aside in time, dragging along with him the new Terrestrial whose shoulder he clutched, and also the surprised Martian skipper. The rocket blasts, dragging fiery fingers across the plain, struck down Haldocott and Jeffords, and bowled over two of the laggards with Shanklin's belated contingent. Then it was away, moving jumpily with its half-wrecked side tubes, but nevertheless escaping.

Parr swore a great oath, that made the stranger gasp. And then Parr had time to see that this was a woman, and young. She was briefly dressed in blouse and shorts, her tawny hair was tumbled, her blue eyes wide. To her still clung the Martian skipper, and Parr covered