animal's muscles tense sharply, and then relax, and after a little tense again. Murgatroyd said almost hysterically:
"Chee-chee-chee-chee!"
Calhoun stopped the car, but Murgatroyd did not seem to be relieved. Allison said impatiently, "What's the matter?"
"That's what I'm trying to find out," said Calhoun.
He felt Murgatroyd's pulse. The role of Murgatroyd in the Med Ship Esclipus Twenty was not only that of charming companion in the long, isolated runs in overdrive. Murgatroyd was a part of the Med Service. His tribe had been discovered on a planet in the Deneb sector, and men had made pets of them, to the high satisfaction of the tormals. Presently it was discovered that veterinarians never had tormals for patients. They were invariably in robustuous good health. They contracted no infections from other animals; they shared no infections with anybody else. The Med Service discovered that tormals possessed a dynamic immunity to germ and bacteria-caused diseases. Even viruses injected into their bloodstreams only provoked an immediate, overwhelming development of antibodies, so that tormals couldn't be given any known disease. Which was of infinite value to the Med Service.
Now every Med Ship that could be supplied with a tormal carried a small, affectionate, whiskered member of the tribe. Men liked them, and they adored men. And when, as sometimes happened, by mutation or the simple enmity of nature, a new kind of infection appeared in human society—why—tormals defeated it. They produced specific antibodies to destroy it. Men analyzed the antibodies and synthesized them, and they were available to all the humans who needed them. So a great many millions of humans stayed alive, because tormals were pleasant little animals with a precious genetic gift of good health.
* * * * *
Calhoun looked at his sweep-second watch, timing the muscular spasms that Murgatroyd displayed. They coincided with irregularities in Murgatroyd's heartbeat, coming at approximately two-second intervals. The tautening of the muscles lasted just about half a second.
"But I don't feel it!" said Calhoun.
Murgatroyd whimpered again and said, "Chee-chee!"
"What's going on?" demanded Allison with the impatience of a very important man indeed. "If the beast's sick, he's sick! I've got to find—"
Calhoun opened his med kit and went carefully through it until he found what he needed. He put a pill into Murgatroyd's mouth.
"Swallow it!" he commanded.
Murgatroyd resisted, but the pill went down. Calhoun watched him sharply. Murgatroyd's digestive system was delicate, but it was dependable. Anything that might be poisonous, Murgatroyd's stomach rejected instantly and emphatically.
The pill stayed down.
"Look!" said Allison indignantly. "I've got business to do! In this attache case I have millions of interstellar credits, in cash, to pay down on purchases of land and factories. I ought to make some damned good deals! And I figure that that's as important as anything else you can think of! It's a damned sight more important than a beast with a belly-ache!"
Calhoun looked at him coldly.
"Do you own land on Texia?" he asked.
Allison's mouth dropped open. Extreme suspicion and unease appeared on his face. As a sign of the unease, his hand went to the side coat pocket in which he'd put a blaster. He didn't pluck it out. Calhoun's left fist swung around and landed. He took Allison's elaborate pocket blaster and threw it away among the monotonous rows of olive-green plants. He returned to absorbed observation of Murgatroyd.
In five minutes the muscular spasms diminished. In ten, Murgatroyd frisked. But he seemed to think that Calhoun had done something remarkable. In the warmest of tones he said:
"Chee!"
"Very good," said Calhoun. "We'll go ahead. I suspect you'll do as well as we do—for a while."
The 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