Park Green looked as though a big weight had been lifted off him.

"Thank heaven for that. I've been worried ever since he gave himself that thymus injection. I thought he might have talked me into letting him do something where he had a big risk. I didn't know enough about all this stuff to argue with him."

Bey smiled at the big man's obvious concern. "Go over to the tank and keep an eye on him if you're at all worried," he said, and signed off the connection.

He strolled back to join Karl Ling, who had now come out of his trance and accepted a cup of syncaff, "compliments of Pleasure Dome." Having broken their standard policy by letting them in free of charge, the staff of Pleasure Domehad apparently decided to adopt them. Ling had just politely refused a Snow Queen's offer of an age-old technique to relax him after all his hard work. He looked rather pleased at her suggestion and quite annoyed when she made the same offer to Bey.

"I think I have the answers, Mr. Wolf, and they are fascinating ones.

More than I dreamed. If I am right, this is a special day in our history."

Ling sat back, relishing the moment.

"Well, Park Green and John La.r.s.en think they have the answers, too," said Bey.

"I've just been in video contact with them."

"They do? Without the evidence that we have available to us here?" Ling's eyebrows were raised. "I can't believe it. What do they think we are dealing with?"

Bey sketched out La.r.s.en and Green's theory. It sounded much thinner than it had when he had first heard it. He summarized the situation back in headquarters and finally mentioned that La.r.s.en was now putting the idea to a practical test.

"He injected an extract from one of the dead men and put himself into a form-change tank?" Ling's self-possession failed him. He turned as white as one of the Snow Queens. "He's a dead man. My G.o.d, why didn't they consult us before they began?"

He sprang to his feet, hurled the records aside, and grabbed for his loose jacket.

"Come on, Mr. Wolf. We must get back as fast as we possibly can. If there is any chance to save John La.r.s.en's life, it depends on our efforts."

He ran out of the room. Bey, bewildered and alarmed, followed him at top speed. When Karl Ling lost his dignity so completely, it was time to worry.

In the elevator, on the Martin Link transfers, and through the ground transit system, Ling rapidly explained the basics of his discoveries to Bey Wolf. By the time they reached the Office of Form Control it was hard to say which man was the more frantic. They went at once to the form-change tanks.

Park Green, alerted as they traveled, was waiting for them there. He looked at Ling as though expecting an outburst of insult and accusation. It did not come. Ling went at once to the tank containing John La.r.s.en and began to read the telltales. After a few minutes he relaxed a little and gave a grunt of satisfaction.

"Everything's still stable. That's good. If he follows the same pattern as the other three, we have about twenty-four hours to do something for him. The one thing I daren't do is stop this process in the middle. We'll have to let it run its course, try to keep him alive while it happens, and worry afterward about reversing it. Bring me the tank schematics. I need to know exactly how the circuits work that control the nutrients and the air supply."

Wolf went for them and was back in less than a minute. Park Green was still standing by the tank, looking totally bewildered. When Ling had the schematics, Green took Bey to one side.

"Mr. Wolf, does he know what he's doing? He's an expert on the Belt, I realize that. But he doesn't know about this stuff, does he? Are we risking John's life by letting him do this?"

Wolf put his hand up to Green's ma.s.sive shoulder. "Believe me, Park, he knows what he's doing. If anyone can help John now, he can do it. We have to give all the help we can and save the questions until later. I'll tell you my views on this when it's all over."

Ling interrupted their conversation. His voice had a rea.s.suring ring of certainty and authority.

"One of you come over here and make a note of the equipment changes that will have to be made. I'll read off the settings as I find them on the charts. The other one of you, call BEC. I want their top specialist on interactive form-change programs. Maria Sun, if she's available, the best they can offer if she isn't. Tell them it's code word circuits, it that will move them faster."

Wolf nodded. "I can get Maria." He hurried out.The equipment modifications began. At every stage Ling rechecked . the telltales. Maria Sun arrived, took one look at the monitors, and settled in by Ling's side. She swore continuously, but it did nothing to lessen her effectiveness as they sweated over the tank. La.r.s.en's condition inside remained stable, but there were big changes occurring. His pulse rate was way down, and there was heavy demand on calcium, nitrogen, and sodium in the nutrient feeds. Skin properties were changing drastically.

"They could have noticed all this in Pleasure Dome if they'd only bothered to look," grunted Ling. "Give them their due, they had no reason to expect anything peculiar. But take a look at that body ma.s.s indicator."

Maria Sun swore a string of oaths. "It's up to a hundred and twenty kilos.

What's his usual weight?"

"Eighty," said Bey, absorbed in watching the indicators. He longed to see inside the tank, but there was no provision for that in the system.

The work went on. After many hours of equipment change and work on program modification with Maria Sun, Ling finally declared that he had done all that he could. The real test would come in a few hours time. That was when the records from the crew of the Jason had begun to go wild. It remained to be seen if the equipment changes could keep La.r.s.en's condition stable as the change proceeded further. The time of watching and waiting began.

As Ling made his final checks on the telltales, Bey realized the mental anguish that Park Green must be going through. He looked at the big man's unhappy face.

"Mr. Ling, have we done all that can be done here?" Bey asked.

"For the moment. The rest is waiting."

"Then, if you will, would you explain all this to us, from the beginning. I got a quick overview on the way here, but Park Green is still in the dark completely, and I'm sure Maria is just as curious."

Ling looked at the three of them as though seeing them for the first time.

Finally, he nodded sympathetically.

"You deserve that, even if I'm wrong. From the beginning, eh? That's a long story. I'll have to tell it to you the way that I imagine it. Whether it's true is another matter."

He sat down, leaned back, and put his hands behind his head.

"I have to begin it sixteen million years ago, and not on Earth. On the planet Loge. Loge was a giant, about ninety Earth ma.s.ses, and it was going to explode. Now for something speculative, something you may find hard to believe. Loge was inhabited. It had living on it a race of intelligent beings.

Maybe they were too intelligent. We know that their planet blew up, and we don't know why. Maybe they were to blame for that. I doubt if we'll ever know.

The race had nuclear energy, but not s.p.a.ceflight."

"Come on now." Maria Sun was looking at Ling skeptically. "You can't possibly know that. I'll buy your Logians, maybe, but you just said we'll never know much about them."

"I know that much, all the same. How do I know it?" Ling was almost pleased by the questioning. "Well, I know that they had nuclear energy because they made transuranic elements. Any natural source of transuranics would have decayed by natural processes since the formation of the planet. The only possible way we could find a source of transuranics on Loge-and only on Loge-would be if they were created there, by nuclear synthesis. We don't know how to do that efficiently ourselves, so there's good reason to think that the Logians had a more advanced nuclear technology than we do."

"All right." Maria nodded her dark head. She had changed her appearance since Bey had last seen her and was now wearing the form of an exquisite Oriental.

The terrible streams of swearing that came out of that petal mouth when she was hard at work made a strange effect that she was probably quite unaware of.

"So, they had nuclear energy. But how could you possibly know they didn't have s.p.a.ceflight?"

"Elementary, my dear Maria." Ling was too engrossed in his explanation to note Bey's quiet reaction to that evidence of prior acquaintance. "They couldn'tescape from Loge, not any of them, even when they found that it was going to disintegrate. They must have had some years of warning, some time to plan-but no one got away, not one of them."

Ling rose from his seat. "Wait one moment, I must check the status." He went to the tank, nodded as he inspected the telltales, and returned. "It is still all stable, and the change is accelerating. The next hour or two is crucial."

"We'll stay here," said Bey. "So they could not get off Loge," he prompted.

"That is correct." Ling resumed his relaxed posture, eyes far away. "They had time to plan, so I imagine it was not a nuclear war. Perhaps they had found a way of making large-scale interior adjustments to the planet and lost control.

That would be relatively slow.

"What could they do? They looked around them in the Solar System. They knew they were going to die, but was there any way that their race might survive?

To a Logian, the natural place for that survival would be Jupiter, or best of all Saturn. They probably never even considered Earth-a tiny planet, by their standards, too hot, oxygen atmosphere, a metal ball crouched close to the Sun.

No, it would have been Jupiter or Saturn, that was their hope. That's where they turned those big, luminous eyes-adapted for seeing well in a murky, methane-heavy atmosphere."

Bey suddenly thought of the great, glowing eyes of the Mariana Monsters as they stood guarding the deeps off Guam. The Grabbers could never have imagined such a fate as they touched down in triumph on the gray surface of Tycho.

"The crew of the Jason," he said.

"You are running ahead of me, Mr. Wolf," said Ling, smiling. "Let me keep the story going, true or false-as I said, all this is pure conjecture. Their scientists calculated the force of the explosion for Loge, and they gave a grim report. No life form, even single-celled ones, could survive it. Parts of Loge would be thrown in all directions. Some would leave the Solar System forever. Some would land in the Sun. And some would undoubtedly hit Jupiter, Saturn, and the other planets-including Earth. Was it possible that anything could survive that explosion and long transit?"

Park Green spoke for the first time. "If single-celled creatures couldn't survive, it would have to be something very primitive. How about a virus?

That's just a chunk of DNA, without any wrapping."

Ling was looking at Green with an expression of surprise. "That's it exactly.

A virus has no 'life-support system' of its own. To grow and multiply, it must have a host cell. The Logians took a chance and packed their genetic material as a viral form."

"And it worked?" asked Maria Sun.

"Not as they expected it to," said Ling. "Or maybe it did. We've never had a ship down to the surface of Jupiter or Saturn, and we don't know what's there.

Maybe there are Logians down there, with viral growth of their genetic materials in host bodies.

"Some of their viral material was on fragments of Loge that were blown way out of the Solar System and became part of the long-period comets. That didn't matter. A virus lasts indefinitely. Sixteen million years later, some of the fragments that fell back into the Solar System under the Sun's gravitational pull were mined by men-not for their Loge DNA, not at all. For their transuranic elements."

"And the Loge DNA began to grow in them?" said Green, his face puzzled. "Wait a minute, that wouldn't work. If that were possible, every Grabber would be ... ".

Ling nodded approvingly. "Very good, Mr. Green. You are quite right. Humans are very poor hosts for Logian development. The Loge virus could get into the human body easily enough, and it could even take up residence in the central nervous system. But it couldn't thrive in those unfamiliar surroundings. Wrong atmosphere, wrong chemical balance, wrong shape."

Ling paused and looked at the other three. His manner had changed. He had become the great scientist, lecturing on his own field to an interested audience."You know, I knew there was a Logian civilization before I ever came to Earth for this investigation. The transuranics proved it, beyond doubt. Otherwise I would never have been led so quickly to this train of thought.

"I think you can now complete the story yourselves. The crew of the Jason picked up Logian DNA in viral form from the fragment that they were crunching for its Asfanium and Polkium. It got into their bodies, and nothing at all happened. They went and had their great celebration in Tycho City, and still nothing happened. But finally they came to Earth-and they got into the form-change machines. At last, the virus could begin to act. It stimulated their central nervous systems, and the purposive form-change process began. It was creating a form that was optimal for Logians, not for Earthmen. When that change had proceeded to the point where the changed form could not survive in the atmosphere of Earth, the creatures died. Asphyxiated, in normal air."

Park was looking at the tank containing John La.r.s.en. He had at last realized the full implications of Ling's words.

"You mean that is happening to John, too?"

"It would have happened, and it would have killed him," replied Ling. "He injected himself with Logian DNA along with the Asfanium he took from the bodies. The work we've been doing this past day has been to modify the life-support system of the tank so that it follows the needs of the organism inside it. If you go and look at the telltales now, you'll find that the nutrients and the atmosphere would be lethal to a human being."

Park Green hurried over to the tank. He looked at the monitors and came quickly back.

"Body ma.s.s, two hundred kilos. Oxygen down below eight percent, and ammonia way up. Mr. Ling, will John live?"

Ling stood up and went over to the tank. He looked carefully at each of the readouts. "I believe he will," he said at last. "The rates of change are down, and everything is very stable. I don't know if we will be able to return him to his former shape. If we can do it, I think it will not be for some time."

Ling came back to the other three. He looked at Bey Wolf and caught the reflection of his own excitement.

"Look on the positive side," he said. "We've dreamed for centuries about our first meeting with an alien race." He nodded toward the great tank. "The first representative will be in there, ready to meet with us, a day or two from now."

BOOK III.

"Let the Great World spin forever, down the ringing grooves of change."

CHAPTER 15.

The external lights had dimmed to their late-night glow. Wolf was sitting by the great tank, half-asleep, musing over the social indicators. His weariness showed in the stiff shoulders, the bowed head, and the slack posture. In front of him, the screen display of the global map revealed concentric circles of change spreading out from the Link entry points. He could visualize the frantic activity in the general coordinators' offices as they sought to stabilize Earth's economic system. Even the long-term indicators-fertility, births, deaths, and change rates-would soon be affected unless the new controls produced better results.

"Sorry to be so 'ong, Bey." The sibilant words from the wall speakers broke suddenly into his drifting thoughts. "The BEC peop'e wanted to test more of my visua' responses. Apparent'y I can see everything from near u'travio'et out through the therma' infrared. Rough'y three-tenths of a micron out to fifteen microns. No wonder I've noticed the wor'd is 'ooking strange these days."

Wolf shook his head, took a deep breath, and sat up straighter in his chair.He turned to look into the tank through its transparent side panels. Inside, John La.r.s.en raised a ma.s.sive, triple-jointed arm and gestured in greeting. His torso was ma.s.sive, wrinkled and ambulated, with a smooth oval area immediately above the central boss that housed the secondary motor nerve center. The broad skull was dominated by the great jeweled eyes and the wide fringed mouth beneath it. La.r.s.en moved his head forward in the movement that Bey had come to recognize as the Logian smile.

"We had a 'ong session," he said, "but at 'east the doctors seem to think I've kept my sanity through a' this-yesterday they didn't sound too sure of that."

As he spoke, forming the words slowly and carefully, the smooth oval area on his chest modulated in color, from a uniform pale pink, to brown, to soft green, following his words like a sound-sensitive visual display.

Wolf smiled wearily. "That's an improvement, then-you never showed much sign of sanity before the change. Ultraviolet through thermal infrared, eh? More than five octaves on the electromagnetic spectrum, and we see less than one.

Can you cover all that range on the chest display?"

"Sure I can. Watch this. Therma' first, then I wi' gradua'y shorten the wave'ength a' the way down. Here we go."

La.r.s.en hooded the nict.i.tating membrane over his prominent eyes and pointed to the smooth area on his chest. Wolf watched in silence. For a while the oval remained gray, then it finally glowed a deep red. Almost imperceptibly, it moved gradually to yellow, then to green, and on to a pale violet-blue before it faded.

Wolf shook his head. "I'll just have to take your word for it, John. I didn't get anything except the usual visual spectrum. You know, you're the ultimate chameleon. When you get through all the tests here, you and I ought to go on a tour. There's been nothing like this in the history of form-change-and we've seen some pretty strange stuff between the two of us."

"I wi' do it, Bey, if you can find a good way of moving me around. You'd have to dup'icate this who'e area." He indicated the inside of the great tank with a wave of a ma.s.sive forearm. "How much did it cost to set this up so I cou'd 'ive in it? It's comfortab'e, but I'm g'ad it didn't have to come out of my sa'ary."

"I don't know what it cost," said Wolf. "Ling set up the credit and made all the physical arrangements before he disappeared again. I guess it all comes out of some USF budget. He certainly had enough credit to impress the proprietors of Pleasure Dome, and we know that's not easy. I still have no word on him, no idea how he got away from here, where he went-anything."

La.r.s.en nodded his broad, wrinkled head, with its wreath of ropy hair. "You won't hear from him again unti' he wants you to, if you ask me. I found out a'ot about him in those few weeks that he was working with me, making sure I cou'd survive a' right in this form. I'm sure you were right in what you said, 'ing is Capman, no doubt of it. He seems to have found ways to move on and off Earth, and round the So'ar System, that we can't even track."

"I know." Wolf rubbed at his chest, his habitual gesture of frustration.

"Losing him once was something that I learned to live with. Losing him the second time is unforgivable-especially when I knew he was Capman, knew it in my bones, long before he took off again. He once said he and I would recognize each other anywhere, regardless of disguise, and I believe him. As soon as you're ready for a reverse change, we'll go and have another look for him. I'm more convinced than ever now that we didn't really understand most of what was going on at Central Hospital."

"I don't know what he did there, Bey, but there's no doubt that he saved my skin."