car lifted the few inches the air columns sustained it above the ground. It went on, still to the eastward. But Calhoun drove more slowly now.
"Something was giving Murgatroyd rhythmic muscular spasms," he said coldly. "I gave him medication to stop them. He's more sensitive than we are, so he reacted to a stimulus we haven't noticed yet. But I think we'll notice it presently."
Allison seemed to be dazed at the affront given him. It appeared to be unthinkable that anybody might lay hands on him.
"What the devil has that to do with me?" he demanded angrily. "And what did you hit me for? You're going to pay for this!"
"Until I do," Calhoun told him, "you'll be quiet. And it does have the devil to do with you. There was a Med Service gadget once—a tricky little device to produce contraction of chosen muscles. It was useful for re-starting stopped hearts without the need of an operation. It regulated the beat of hearts that were too slow or dangerously irregular. But some businessman had a bright idea and got a tame researcher to link that gadget to ground induction currents. I suspect you know that businessman!"
"I don't know what you're talking about," snapped Allison. But he was singularly tense.
"I do," said Calhoun unpleasantly. "I made a public health inspection on Texia a couple of years ago. The whole planet is a single, gigantic, cattle-raising enterprise. They don't use metal fences—the herds are too big to be stopped by such things. They don't use cowboys—they cost money. On Texia they use ground-induction and the Med Service gadget linked together to serve as cattle fences. They act like fences, though they're projected through the ground. Cattle become uncomfortable when they try to cross them. So they draw back. So men control them. They move them from place to place by changing the cattle fences, which are currents induced in the ground. The cattle have to keep moving or be punished by the moving fence. They're even driven into the slaughterhouse chutes by ground-induction fields! That's the trick on Texia, where induction fields herd cattle. I think it's the trick on Maya, where people are herded like cattle and driven out of their cities so the value of their fields and factories will drop,—so a land buyer can find bargains!"
"You're insane!" snapped Allison. "I just landed on this planet! You saw me land! I don't know what happened before I got here! How could I?"
"You might have arranged it," said Calhoun.
* * * * *
Allison assumed an air of offended and superior dignity. Calhoun drove the car onward at very much less than the head-long pace he'd been keeping to. Presently he looked down at his hands on the steering wheel. Now and then the tendons to his fingers seemed to twitch. At rhythmic intervals, the skin crawled on the back of his hands. He glanced at Allison. Allison's hands were tightly clenched.
"There's a ground-induction fence in action, all right," said Calhoun calmly. "You notice? It's a cattle fence and we're running into it. If we were cattle, now, we'd turn around and move away."
"I don't know what you're talking about!" said Allison.
But his hands stayed clenched. Calhoun slowed the car still more. He began to feel, all over his body, that every muscle tended to twitch at the same time. It was a horrible sensation. His heart muscles tended to contract too, simultaneously with the rest, but one's heart has its own beat rate. Sometimes the normal beat coincided with the twitch. Then his heart pounded violently—so violently that it was painful. But equally often the imposed contraction of the heart muscles came just after a normal contraction, and then it stayed tightly knotted for half a second. It missed a beat, and the feeling was agony.
No animal would have pressed forward in the face of such sensations. It would have turned back long ago. No animal. Not even Man.
Calhoun stopped the car. He looked at Murgatroyd. Murgatroyd was completely himself. He looked inquiringly at Calhoun. Calhoun nodded to him, but he spoke—with some difficulty—to Allison.
"We'll see—if this thing—builds up. You know that it's the Texia—trick. A ground-induction unit set up—here. It drove people—like cattle. Now we've—run into it.—It's holding people—like cattle."
He panted. His chest muscles contracted with the rest, so that his breathing was interfered with. But Murgatroyd, who'd been made uneasy and uncomfortable before Calhoun noticed anything wrong, was now bright and frisky. Medication had desensitized his muscles to outside stimuli. He would be able to take a considerable electric shock without responding to it.
But he could be killed by one that was strong enough.
A savage anger filled Calhoun. Everything fitted together. Allison had put his hand convenient to his blaster when Calhoun mentioned Texia. It meant that Calhoun suspected what Allison knew to be true. A cattle-fence unit had been set up on Maya, and it was holding—like cattle—the people it had previously driven—like cattle. Calhoun could deduce with some precision exactly what had been done. The first experience of Maya with the cattle fence would have been very mild. It would have been low-power, causing just enough uneasiness to be noticed. It would have moved from west to east, slowly, and it would have reached a certain spot and there faded out. And it would have been a mystery and an uncomfortable thing, and nobody would understand it on Maya. In a week it would almost be forgotten. But then there'd come a stronger disturbance. And it would travel like the first one; down the length of the peninsula on which the colony lay, but stopping at the same spot as before, and then fading away to nothingness. And this also would have seemed mysterious. But nobody would suspect humans of causing it. There would be theorizing and much questioning, but it would be considered an unfamiliar natural event.
Probably the third use of the cattle fence would be most disturbing. This time it would be acutely painful. But it would move into the cities and through them and past them, and it would go down the peninsula to where it had stopped and faded on two previous occasions.
The people of Maya would be disturbed and scared. But they considered that they knew it began to the westward of Maya City, and moved toward the east at such-and-such a speed, and it went so far and no farther. And they would organize themselves to apply this carefully worked out information.
It would not occur to any of them that they had learned how to be driven like cattle.
* * * * *
Calhoun, of course, could only reason that this must have happened. But nothing else could have taken place. Perhaps there were more than three uses of the moving cattle fence to get the people prepared to move past the known place at which it always faded to nothingness. They might have been days apart, or weeks apart, or months. There might have been stronger manifestations followed by weaker ones and then stronger ones again.
But there was an inductive cattle fence across the highway here. Calhoun had driven into it. Every two seconds the muscles of his body tensed. Sometimes his heart missed a beat at the time that his breathing stopped, and sometimes it pounded violently. It seemed that the symptoms became more and more unbearable.
He got out his med kit, with hands that spasmodically jerked uncontrollably. He fumbled out the same medication he'd given Murgatroyd. He took two of the pellets.
"In reason," he said coldly, "I ought to let you take what this damned thing would give you. But—here!"
Allison had panicked. The idea of a cattle fence suggested discomfort, of course, but it did not imply danger. The experience of a cattle fence, designed for huge hoofed beasts instead of men, was terrifying. Allison gasped. He made convulsive movements. Calhoun himself moved erratically. For one and
