'Twenty-two,' the computer nurse said. 'Twenty-one nine... twenty-two... twenty-one nine... twenty-two one... twenty-two two... twenty-two one... twenty-two two... twenty-two three... twenty-two four... twenty-two three... twenty-two four... twenty-two five... twenty- two six... twenty-two five...'

Potter felt the see-saw battle through every nerve. The morula was down at the edge of the death range. It could live or it could die in the next few minutes. Or it could come out of this crippled. Such things happened. When the flaw was too gross, the vat was turned off, flushed out. But Potter felt an identification with this embryo now. He felt he couldn't afford to lose it.

'Mutagen desensitizer,' he said.

Svengaard hesitated. The Krebs cycle was following a slow sine curve that dipped perilously into the death cycle now. He knew why Potter had made his decision, but the carcinogenic peril of it had to be weighed. He wondered if he should argue the step. The embryo hung less than four points from a deadly plunge into dissolution. Chemical mutagens administered at this point could shock it into a spun of growth or destroy it. Even if the mutagen treatment worked, it could leave the embryo susceptible to cancer.

'Mutagen desensitizer!' Potter repeated.

'Dosage?' Svengaard asked. 'Half minim on fractional-minim feed. I'll control it from here.'

Svengaard shifted the feeder keys, his eyes on the Krebs-cycle repeater. He'd never heard of applying such drastic treatment this close to the borderline. Mutagens usually were reserved for the partly-flawed Sterrie embryo, a move that sometimes produced dramatic results. It was like shaking a bucket of sand to level the grains. Sometimes the germ plasm presented with a mutagen sought a better level on its own. They'd even produced an occasional viable this way... but never an Optiman.

Potter reduced amplification, studied the flow of movement in the embryo. Gently, he depressed the feeder key, searched for Optiman signs. The cellular action remained unsteady, partly blurred.

'Krebs cycle twenty-two eight,' the computer nurse said.

Climbing a bit. Potter thought.

'Very slow,' Svengaard said.

Potter maintained his vigil within the morula. It was growing, expanding in fits and starts, fighting with all the enormous power contracted in its tiny domain.

'Krebs cycle thirty point four,' Svengaard said.

'I am withdrawing mutagens,' Potter said. He backed off the microscope to a peripheral cell, desensitized the nucleo-proteins, searched for the flawed configurations.

The cell was clean.

Potter traced down into the coiled-coil helices of the DNA chains with a dawning wonder.

'Krebs cycle thirty-six eight and climbing,' Svengaard said. 'Shall I start the choline and aneurin?'.

Potter spoke automatically, his attention fixed on the cell's gene structure. 'Yes, start them.' He completed the scope tracing, shifted to another peripheral cell.

Identical.

Another cell - the same.

The altered gene pattern held true, but it was a pattern, Potter realized, which hadn't been seen in humankind since the second century of gene shaping. He thought of calling for a comparison to be sure. The computer would have it, of course. No record was ever lost or thrown away. But he dared not... there was too much at stake in this. He knew he didn't need the comparison, though. This was a classic form, a classroom norm which he had stared at almost daily all through his medical education.

The super-genius pattern that had caused Sven to call in a Central specialist was there, firmed up by the cutting-room adjustments. It was close-coupled, though, with a fully stable fertility pattern. The longevity basics lay locked in the configurations of the gene structure.

If this embryo reached maturity and encountered a fertile mate, it could breed healthy, living children without the interference of the genes surgeon. It needed no enzyme prescription to survive. It would outlive ten standard humans without that prescription... and with a few delicate enzymic adjustments might join the ranks of the immortals.

The Durant embryo could father a new race - like the live-forevers of Central, but dramatically unlike them. This embryo's progeny might fit themselves into the rhythms of natural selectivity... completely outside Optiman control.

It was the template pattern from which no human could deviate too far and live, yet it was the single thing feared most by Central.

Every gene surgeon had this drummed into him during his education, 'Natural selectivity is a madness that sends its human victims groping blindly through empty lives.' Optiman reason and Optiman logic must do the selecting. As though he straddled Time, Potter felt the profound certainty that the Durant embryo, if it matured, would encounter a fertile mate. This embryo had received a gift from outside -a wealth of sperm-arginine, the key to its fertility pattern. In the flood of mutagen which opened the active centers of the DNA, this embryo's gene patterns had shaken down into a stable form no human dared attempt.

Why did I introduce the mutagens just then? Potter wondered. I knew it was the needed thing. How did I know? Was I an instrument of some other force?

'Krebs cycle fifty-eight and climbing steadily,' Svengaard said.

Potter longed for the freedom to discuss this problem with Svengaard... but there were the damnable parents and the Security people... watching. Was it possible anyone else had seen enough and knew enough of this pattern to realize what had happened here? he wondered. Why did I introduce the mutagens?

'Can you see the pattern yet?' Svengaard asked.

'Not yet,' Potter lied.

The embryo was growing rapidly now. Potter studied the proliferation of stable cells. It was beautiful. 'Krebs cycle sixty-four seven,' Svengaard said. I've waited too long. Potter thought. The big domes of Central will ask why I waited so long to kill this embryo. I cannot kill it! It's too beautiful.

Central maintained its power by keeping the world at large in ignorance of the ruling fist, by doling out living time in the form of precious enzyme prescriptions to its half-alive slaves.

The Folk had a saying: 'In this world there are two worlds - one that works not and lives forever; one that lives not and works forever.'

Here in a crystal vat lay a tiny ball of cells, a living creature less than six-tenths of a millimeter in diameter, and it carried the full potential of living out its life beyond Central's control.

This morula had to die.

They'll order it killed. Potter thought. And I will be suspect... finished. And if this thing did get loose in the world, what then? What would happen to gene surgery? Would we go back to correcting the minor defects... the way it was before we started shaping supermen?

Supermen!

In his mind, he did what no voice could do: he cursed the Optimen. They were enormous power, instant life or death. Many were geniuses. But they were as dependent on the enzymic fractions as any clod of the Sterries or Breeders. There were men as brilliant among the Sterries and Breeders... and among the surgeons.

But none of these could live forever, secure in that ultimate brutal power.

'Krebs cycle one hundred even,' Svengaard said.

'We're over the top now,' Potter said. He risked a glance at the computer nurse, but she had her back to him, fussing with her board. Without that computer record, it might be possible to conceal what had happened here. With that record open to examination by Security and by the Optimen, it could not be hidden. Svengaard had not seen enough. The forehead lens only approximated the full field of vision. The vat nurses couldn't even guess at it. Only the computer nurse with her tiny monitor screen might know... and the full record lay in her machine now - a pattern of magnetic waves on strips of tape.

'That's the lowest I've ever seen it go without killing the embryo,' Svengaard said.

'How low?' Potter asked.

'Twenty-one nine,' Svengaard said. 'Twenty's bottom, of course, but I've never heard of an embryo coming back from below twenty-five before, have you. Doctor?'

'No,' Potter said.

'Is it the pattern we want?' Svengaard asked. 'I don't want to interfere too much yet,' Potter said.

'Of course,' Svengaard said. 'Whatever happens, it was inspired surgery.'

Inspired surgery! Potter thought. What would this dolt say if I told him what I have here? A totally viable embryo! A total. Kill it, he'd say. It'll need no enzyme prescription and it can breed true. It hasn't a defect.. not one. Kill it, he'd say. He's a dutiful slave. The whole sorry history of gene shaping could be justified by this one embryo. But the minute they see this tape at Central, the embryo will be destroyed.

Eliminate it, they'll say... because they don't like to use words too close to kill or death.

Potter bent to the scope. How lovely the embryo was in its own terrifying way.

He risked another glance at the computer nurse. She turned, mask down, met his gaze, smiled. It was a knowing, secretive smile, the smile of a conspirator. Now, she reached up to mop the perspiration from her face. Her sleeve brushed a switch. A rasping whirring scream came from the computer board. She whirled to it, grated, 'Oh, my God!' Her hands sped over the board, but tape continued to hiss through the transponder plates. She turned, tried to wrestle the transparent cover from the recording console. The big reels whirled madly under the cover plate.

'It's running wild!' she shouted.

'It's locked on Erase!' Svengaard yelled. He jumped to her side, tried to get the cover plate off. It jammed in its tracks.

Potter watched like a man in a trance as the last of the tape flashed through the heads, began whipping on the take-up reels.

'Oh, Doctor, we've lost it!' the computer nurse wailed.

Potter focused on the little monitor screen at the computer nurse's station. Did she watch the operation closely? he asked himself. Sometimes they follow the cut move by move... and computer nurses are a savvy lot. If she watched, she'll have a good idea what we achieved. At the very least, she'll suspect. Was that tape erasure really an accident? Do I dare?

She turned, met his gaze. 'Oh, Doctor, I'm so sorry,' she said.

'It's all right, nurse,' Potter said. 'There's nothing very special about this embryo now, aside from the fact that it will live.'

'We missed it, eh?' Svengaard asked. 'Must've been the mutagens.'

'Yes,' Potter said. 'But without them it'd have died.'

Potter stared at the nurse. He couldn't be sure, but he thought he saw a profound relief wash over her features.

'I'll cut a verbal tape of the operation,' Potter said. 'That should be enough on this embryo.'

And he thought. When does a conspiracy begin? Was this such a beginning?

There was still so much this conspiracy required. No knowledgeable eye could ever again look at this embryo through the microscope without being a part of the conspiracy... or a traitor.

'We still have the protein synthesis tape,' Svengaard said. 'That'll give us the chemical factors by reference - and the timing.'

Potter thought about the protein synthesis tape. Was there danger in it? No, it was only a reference for what had been used in the operation... not how anything had been used.

'So it will,' Potter said. 'So it will.' He gestured to the monitor screen. 'Operation's finished. You can cut the direct circuit and escort the parents to the reception room. I'm very sorry we achieved no more than we did, but this'll be a healthy human.'

'Sterrie?' Svengaard asked. 'Too soon to guess,' Potter said. He looked at the computer nurse. She managed to get the cover off at last and had stopped the tapes. 'Any idea how that happened?'

'Probably a solonoid failure,' Svengaard said.

'This equipment's quite old,' the nurse said. 'I've asked for replacement units several times, but we don't seem to be very high on the priority lists.'

And there's a natural reluctance at Central to admit anything can wear out. Potter thought.

'Yes,' Potter said. 'Well, I daresay you'll get your replacements now.'

Did anyone else see her trip that switch? Potter wondered. He tried to remember where everyone in the room had been looking, worried that a Security monitor might've been watching her. If Security saw that, she's dead. Potter thought. And so am I.

'The technician's report on repairs will have to be part of the record on this case,' Svengaard said. 'I presume you'll- ' 'I'll see to it personally. Doctor,' she said, Turning away. Potter had the impression that he and the computer nurse had just carried on a silent conversation. He noted that the big screen was now a gray blank, the Durants no longer watching. Should I see them myself? he wondered. If they're part of the Underground, they could help. Something has to be done about the embryo. Safest to get it out of here entirely... but how?

'I'll take care of the tie-off details,' Svengaard said. He began checking the vat seals, life systems repeaters, dismantling the meson generator.

Someone has to see the parents. Potter thought. 'The parents'll be disappointed,' Svengaard said. 'They generally know why a specialist is called in... and probably got their hopes up.'

The door from the ready room opened to admit a man Potter recognized as an agent from Central Security. He was a moonfaced blond with features one tended to forget five minutes after leaving him. The man crossed the room to stand in front of Potter.

Is this the end for me? Potter wondered. He forced his voice into a steady casual tone, asked, 'What about the parents?'

'They're clean,' the agent said. 'No tricky devices - conversation normal... plenty of small talk, but normal.'

'No hint of the other things?' Potter asked. 'Any way they could've penetrated Security without instruments?'

'Impossible!' the man snorted.

'Doctor Svengaard believes the father's overly endowed with male protectiveness and the mother has too much maternalisms,' Potter said.

'The records show you shaped 'em,' the agent said.

'It's possible,' Potter said. 'Sometimes you have to concentrate on gross elements of the cut to save the embryo. Little things slip past.'

'Anything slip past on this one today?' the agent asked. 'I understand the tape's been erased... an accident.'

Does he suspect? Potter asked himself. The extent of his own involvement and personal danger threatened to overwhelm Potter. It took the greatest effort to maintain a casual tone.

'Anything's possible of course,' Potter said. He shrugged. 'But I don t think we have anything unusual here. We lost the Optishape in saving the embryo, but that happens. We can't win them all.'

'Should we flag the embryo's record?' the agent asked.

He's still fishing. Potter told himself. He said, 'Suit yourself. I'll have a verbal tape on the cut pretty soon - probably just as accurate as the visual one. You might wait and analyze that before you decide.'

'I'll do that,' the agent said.

Svengaard had the microscope off the vat now. Potter relaxed slightly. No one was going to take a casual, dangerous look at the embryo.

'I guess we brought you on a wild goose chase,' Potter said. 'Sorry about that, but they did insist on watching.'

'Better ten wild goose chases than one set of parents knowing too much,' the agent said. 'How was the tape erased?'

'Accident,' Potter said. 'Worn equipment. We'll have the technical report for you shortly.'

'Leave the worn equipment thing out of your report,' the agent said. 'I'll take that verbally. Allgood has to show every report to the Tuyere now.'

Potter permitted himself an understanding nod. 'Of course.' The men who worked out of Central knew about such things. One concealed personally disquieting items from the Optimen.

The agent glanced around the cutting room, said, 'Someday we won't have to use all this secrecy. Won't come any too soon for me.' He turned away.

Potter watched the retreating back, thinking how neatly the agent fitted into the demands of his profession. A superb cut with just one flaw - too neat a fit, too much cold logic, not enough imaginative curiosity and readiness to explore the avenues of chance.

If he'd pressed me, he'd have had me. Potter thought. He should've been more curious about the accident. But we tend to copy our masters - even in their blind spots.

Potter began to have more confidence of success in his impetuous venture. He turned back to help Svengaard with the final details, wondering. How do I know the agent's satisfied with my explanation. No feeling of disquiet accompanied the question. If know he's satisfied, but how do I know it? Potter asked himself.

He realized then that his mind had been absorbing correlated gene information - the inner workings of the cells and their exterior manifestations - for so many years that this weight of data had fused into a new level of understanding. He was reading the tiny betrayals in gene- type reactions.