THE MECHANIC

 

Drifting idly, the Shark tended to look more like a manta ray than her name suggested; but at high cruise, as she was now, she bore more resemblance to a flying fish. She was entirely out of the water except for the four struts that carried her hydroplanes; the air propellers which drove her were high enough above the surface to raise very little spray. An orbiting monitor satellite could have seen the vessel herself from a hundred miles up, since her upper hull was painted in a vividly fluorescent pattern of red and yellow; but there was not enough wake to suggest to such a watcher that the wedge-shaped machine was traveling at nearly sixty-five knots. 

Chester V. Winkle—everyone knew what the middle initial stood for, but no one mentioned it in his presence—sat behind the left bow port of his command with his fingers resting lightly on the pressure controls. He was looking ahead, but knew better than to trust his eyes alone. Most of his attention was devoted to the voice of the smaller man seated four feet to his right, behind the other "eye" of the manta. Yoshii Ishihara was not looking outside at all; his eyes were directed steadily at the sonar display screen which was all that stood between the Shark and disaster at her present speed among the ice floes and zeowhales of the Labrador Sea. 

"Twenty-two targets in the sweep; about fourteen thousand meters to the middle of the group," he said softly. 

"Heading?" Winkle knew the question was superfluous; had a change been in order, the sonarman would have given it. 

"As we go, for thirty-two hundred meters. Then twenty-two mils starboard. There's ice in the way." 

"Good. Any data on target condition yet?" 

"No. It will be easier to read them when we stop, and will cost little time to wait. Four of the twenty-two are drifting, but the sea is rich here and they might be digesting. Stand by for change of heading." 

"Ready on your call." There was silence for about a minute. "Starboard ten." 

"Starboard ten." The hydroplanes submerged near the ends of the Shark's bow struts banked in response to the pressure of Winkle's fingers, though the hull remained nearly level. The compass needle on the panel between the view ports moved smoothly through ten divisions. As it reached the tenth Ishihara, without looking up from his screen, called, "Steady." 

"Steady she is," replied the commander. 

"Stand by for twelve more to starboard—now." The Shark swung again and steadied on the new heading. 

"That leaves us a clear path in," said the sonarman. "Time to engine cut is four minutes." 

In spite of his assurance that the way was clear, Ishihara kept his eyes on his instruments—his standards of professional competence would permit nothing less while the Shark had way on her. Winkle, in spite of the sleepy appearance which combined with his name to produce a constant spate of bad jokes, was equally alert for visible obstructions ahead. Several ice floes could be seen, but none were directly in the vessel's path, and Winkle's fingers remained idle until his second officer gave the expected signal. 

Then the whine of turbines began to drop in pitch, and the Shark's broad form eased toward the swell below as the hydrofoils lost their lift. The hull extensions well out on her "wings" which gave the vessel catamaran-type stability when drifting kissed the surface gently, their added drag slowing the machine more abruptly; and twenty feet aft of the conning ports the four remaining members of the crew tensed for action. 

"Slow enough for readings?" asked Winkle. 

"Yes, sir. The homing signal is going out now. I'll have counts in the next thirty seconds." Ishihara paused. "One of the four drifters is underway and turning toward us. No visible response from the others." 

"Which is the nearest of the dead ones?" 

"Fifteen hundred meters, eight hundred forty mils port." Winkle's fingers moved again. The turbines that drove the big, counter-rotating air propellers remained idle, but water jets playing from ducts on the hydrofoil struts swung the ship in the indicated direction and set her traveling slowly toward the drifter. Winkle called an order over his shoulder. 

"Winches and divers ready. The trap is unsafetied. Contact in five minutes?" 

"Winch ready," Dandridge's deep voice reported as he swept his chessboard to one side and closed a master switch. Mancini, who had been facing him across the board, slipped farther aft to the laboratory which occupied over half of the Shark's habitable part. He said nothing, since no order had been directed at him, and made no move to uncage any of his apparatus while the vessel was still in motion. 

"Divers standing by." Farrell spoke for himself and his assistant after a brief check of masks and valves—both were already dressed for Arctic water. They took their places at either side of the red-checkered deck area, just forward of the lab section, which marked the main hatch. Dandridge, glancing up to make sure that no one was standing on it, opened the trap from his control console. Its halves slid smoothly apart, revealing the chill green liquid slipping between the hulls. At the Shark's present speed she was floating at displacement depth, so that the water averaged about four meters down from the hatch; but this distance was varied by a swell of a meter or so. Farrell stood looking down at it, wailing patiently for the vessel to stop; his younger assistant dropped prone by the edge of the opening and craned his neck through it in an effort to see forward. 

Ishihara's voice was barely audible over the wind now that the hatch was open, but occasional words drifted back to the divers. "Six hundred... as you go...four...three..." 

"I see it," Winkle cut in. "I'll take her." He called over his shoulder again, "Farrell...Stubbs...we're coming up on one. You'll spot it in a minute. I'll tell you when I lose it under the bow." 

"Yes, sir," acknowledged Farrell. "See it yet, Rick?" 

"Not yet," was the response. "Nothing but jellyfish." 

"Fifty meters," called the captain. "Now thirty." He cut the water jets to a point where steerage way would have been lost if such a term had meant anything to the Shark, and continued to inch forward. "Twenty." 

"I see it," called Stubbs. 

"All right," answered the captain. "Ten meters. Five. It's right under me; I've lost it. Con me, diver." 

"About five meters, sir. It's dead center...four...three...two...all right, it's right under the hatch. Magnets ready, Gil?" 

The magnetic grapple was at the forward end of its rail, directly over the hatch, so Dandridge was ready; but Winkle was not. 

"Hold up...don't latch on yet. Stubbs, watch the fish; are we drifting?" 

"A little, sir. It's going forward and a little to port...now you're stopping it...there." 

"Quite a bit of wind," remarked the captain as his fingers lifted from the hydrojet controls. "All right. Pick it up." 

"Think the magnets will be all right, Marco?" asked Dandridge. "That whale looks funny to me." The mechanic joined the winchman and divers at the hatch and looked down at their floating problem. 

At first glance the "whale" was ordinary enough. It was about two meters long, and perfectly cigar-shaped except where the intake ring broke the curve some forty centimeters back of the nose. The exhaust ports, about equally far from the tail end, were less visible since they were merely openings in the dark gray skin. Integument and openings alike were hard to see in detail, however; the entire organism was overgrown with a brownish, slimy-looking mass of filaments reminiscent both of mold and of sealskin. 

"It's picked up something, all right," Mancini conceded. "I don't see why your magnets shouldn't work, though ... unless you'd rather they didn't get dirty." 

"All right. Get down the ladder and steer 'em, Rick." Dandridge caused a light alloy ladder to extend from the bow edge of the hatch as he spoke; then he fingered another switch which sent the grapples themselves slowly downward. Stubbs easily beat them to the foot of the ladder, hooked one leg through a rung, reached out with both arms and tried to steady the descending mass of metal. The Shark was pitching somewhat in the swell, and the eighty pounds of electromagnet and associated wiring was slightly rebellious. The youngest of the crew and the only nonspecialist among its members—he was still working off the two-year labor draft requirement which preceded higher education—Rick Stubbs got at least his share of the dirty work. He was not so young as to complain about it. 

"Slower...slower...twenty c's to go...ten...hold it now... just a touch lower all right, juice!" Dandridge followed the instructions, fed current to the magnets, and started to lift, 

"Wait!" the boy on the ladder called almost instantly. "It's not holding!" 

The mechanic reacted almost as fast. 

"Bring it up anyway!" he called. "The infection is sticking to the magnets. Let me get a sample!" Stubbs shrank back against the ladder as the slimy mass rose past him. In response to Mancini's command. Dandridge grimaced with distaste as it came above deck level and into his view. 

"You can have it!" he remarked, not very originally. 

Mancini gave no answer, and showed no sign of any emotion but interest. He had slipped back into his lab as the material was ascending, and now returned with a two-liter flask and the biggest funnel he possessed. 

"Run it aft a little," he said briefly. "That's enough...I'll miss some, and it might as well fall into the water as onto the deck." The grapple, which had crawled a few inches toward him on its overhead rail, stopped just short of the after edge of the hatch. Mancini, standing unconcernedly at the edge of the opening with the wind ruffling his clothes, held funnel and flask under the magnets. 

"All right, Gil, drop it," he ordered. Dandridge obeyed. 

Most of the mess fell obediently away from the grapple. Some landed in the funnel and proceeded to ooze down into the flask; some hit Mancini's extended arm without appearing to bother him; a little dropped onto the deck, to the winchman's visible disgust. Most fell past Stubbs back into the sea. 

The mechanic took up some of the material from his arm and rubbed it between thumb and forefinger. "Gritty," he remarked. "And the magnets held this stuff, but not the whale's skeleton. That means that most of the skeleton must be gone, and I bet this grit is magnetite. I'll risk a dollar that this infection comes from that old 775-Fe-DE6 culture that got loose a few years ago from Passamaquoddy. I'll give it the works to make sure, though. You divers will have to use slings to get the fish aboard, I'm afraid." 

"Rick, I'll send the magnets down first and you can rinse 'em off a bit in the water. Then I'll run out the sling and you can get it around the whale." 

"All right, sir. Standing by." As the grapple went down again Dandridge called to the mechanic, who had turned back toward the lab. 

"I suppose the whale is ruined, if you're right about the infection. Can we collect damages?" Mancini shook his head negatively. 

"No one could collect from DE: they went broke years ago—from paying damages. Besides, the courts decided years ago that injury or destruction of a piece of pseudolife was recoverable property damage only if an original model was involved. This fish is a descendant of a model ten years old; it was born at sea. We didn't make it and can't recover for it." He turned to his bench, but flung a last thought over his shoulder. "My guess that this pest is a DE escapee could be wrong, too. They worked out a virus for that strain a few months after it escaped, and I haven't heard of an iron infection in four years. This may be a mutation of it—that's still my best guess—but it could also be something entirely new." He settled himself onto a stool and began dividing the material from the flask into the dozens of tiny containers which fed the analyzers. 

In the water below, Stubbs had plunged from the ladder and was removing slime from the grapple magnets. The stuff was not too sticky, and the grit which might be magnetite slightly offset the feeling of revulsion which the boy normally had for slimy materials, so he was able to finish the job quickly enough to keep Dandridge happy. At Rick's call, the grapple was retracted; a few moments later the hoist cable came down again with an ordinary sling at its extremity. Stubbs was still in the water, and Farrell had come part way down the ladder. The chief diver guided the cable down to his young assistant, who began working the straps around the torpedo-like form which still bobbed between the Shark's hulls. 

It was quite a job. The zeowhale was still slippery, since the magnets had not come even close to removing all the foreign growth. When the boy tried to reach around it to fasten the straps it slithered away from him. He called for more slack and tried to pin it against one of the hulls as he worked, but still it escaped him. He was too stubborn to ask for help, and by this time Farrell was laughing too hard to have provided much anyway. 

"Ride him, Buster!" the chief diver called as Stubbs finally managed to scissor the slippery cylinder with his legs. "That's it...you've got him dogged now!" 

The boy hadn't quite finished, actually, but one strap did seem secure around the forward part of the hull. "Take up slack!" he called up to the hatch, without answering Farrell's remark. 

Dandridge had been looking through the trap and could see what was needed; he reached to his control console and the hoist cable tightened. 

"That's enough!" called Stubbs as the nose of the zeowhale began to lift from the water. "Hold it until I get another strap on, or this one will slip free!" 

Winches obediently ceased purring. With its motion restrained somewhat, the little machine offered less opposition to the attachment of a second band near its stern. The young swimmer called, somewhat breathlessly, "Take it up!" and paddled himself slowly back to the ladder. Farrell gave him a hand up, and they reached the deck almost as quickly as the specimen. 

Dandridge closed the hatch without waiting for orders, though he left the ladder down—there would be other pickups in the next few minutes, but the wind was cold and loud. Stubbs paid no attention; he barely heard the soft "Eight hundred meters, seventy-five mils to starboard," as he made his way around the closing hatch to Mancini's work station. The mechanic's job was much more fascinating than the pilot's. 

He knew better than to interrupt a busy professional with questions, but the mechanic didn't need any. Like several other men, not only on the Shark but among the crew of her mother ship, Mancini had come to like the youngster and respect his general competence; and like most professionals, his attitude toward an intelligent labor draftee was a desire to recruit him before someone else did. The man, therefore, began to talk as soon as he noticed the boys presence. 

"You know much about either chemical or field analysis, Rick?" 

"A little. I can recognize most of your gear—ultracentrifuge, chromatographic and electrophoretic stuff, NMR equipment, and so on. Is that," he pointed to a cylindrical machine on another bench, "a diffraction camera?" 

"Good guess. It's a hybrid that a friend of mine dreamed up which can be used either for electron microphotography or diffraction work. All that comes a bit later, though. One thing about analysis hasn't changed since the beginning; you try to get your initial sample into as many different homogeneous parts as possible before you get down to the molecular scale." 

"So each of these little tubes you're filling goes through centrifuge, or solvation, or electrophoresis—" 

"More usually, through all of them, in different orders." 

"I should think that just looking at the original, undamaged specimen would tell you something. Don't you ever do that?" 

"Sure. The good old light microscope will never disappear; as you imply, it's helpful to see a machine in its assembled state, too. I'll have some slides in a few more seconds; the mike is in that cabinet. Slide it out, will you?" 

Stubbs obeyed, literally since the instrument was mounted on a track. The designers of the Shark's laboratory had made it as immune to rough weather as they could. Mancini took the first of his slides, clipped it under the objective, and took one look. 

"Thought so," he grunted. "Here, see for yourself." 

Stubbs applied an eye to the instrument, played briefly with the fine focus—he had the normal basic training in fundamental apparatus—and looked for several seconds. 

"Just a mess of living cells that don't mean much to me, and a lot of little octahedra. Are they what you mean?" 

"Yep. Magnetite crystals, or I'm a draft-dodger." (His remark had no military significance; the term now referred to individuals who declined the unskilled-labor draft, voluntarily giving up their rights to higher education and, in effect, committing themselves to living on basic relief.) "We'll make sure, though." The mechanic slid another piece of equipment into position on the microscope stage, and peered once more into the field of view. Stubbs recognized a micromanipulator, and was not surprised when Mancini, after two minutes or so of silent work, straightened up and removed a small strip of metal from it. Presumably one of the tiny crystals was now mounted on the strip. 

The mechanic turned to the diffraction camera, mounted the bit of metal in a clamp attached to it, and touched a button which started specimen and strip on a journey into the camera's interior. Moments later a pump started to whine. 

"Five minutes to vacuum, five more for scanning," he remarked. "We might as well have a look at the fish itself while we wait; even naked-eye examination has its uses." He got up from his seat, stretched, and turned to the bench on which the ruined zeowhale lay. "How much do you know about these things, Rick? Can you recognize this type?" 

"I think so. I'd say it was a copper-feeder of about '35 model. This one would be about two years old." 

"Good. I'd say you were about right. You've been doing some reading, I take it." 

"Some. And the Guppy's shop is a pretty good museum." 

"True enough. Do you know where the access regions are on this model?" 

"I've seen some of them opened up, but I wouldn't feel sure enough to do it myself." 

"It probably wouldn't matter if you did it wrong in this case; this one is safely dead. Still, I'll show you; better see it right than do it wrong." He had removed the straps of the sling once the "fish" had been lowered onto a rack on the bench, so nothing interfered with the demonstration. "Here," he pointed, "the reference is the centerline of scales along the back, just a little lighter in color than the rest. Start at the intake ring and count eight scales back; then down six on either side, like that. That puts you on this scale...so...which you can get under with a scalpel at the start of the main opening." He picked up an instrument about the size of a surgical scalpel, but with a blunt, rounded blade. This he inserted under the indicated scale. "See, it comes apart here with very light pressure, and you can run the cut back to just in front of the exhaust vents—like that. If this were a living specimen, the cut would heal under sealant spray in about an hour after the fish was back in the water. This one... hm-m-m. No wonder it passed out. I wonder what this stuff is?" 

The body cavity of the zeowhale was filled with a dead-black jelly, quite different in appearance from the growth which had covered the skin. The mechanic applied retractors to the incision, and began silently poking into the material with a variety of "surgical" tools. He seemed indifferent to the feelings which were tending to bring Stubbs' stomach almost as much into daylight as that of the whale. 

Pieces of rubbery internal machinery began to litter the bench top. Another set of tiny test tubes took samples of the black jelly, and followed their predecessors into the automatic analyzers. These began to hum and sputter as they went to work on the new material—they had long since finished with the first load, and a pile of diagrams and numerical tables awaited Mancini's attention in their various delivery baskets. He had not even taken time to see whether his guess about magnetite had been good. 

Some of the organs on the desk were recognizable to the boy—for any large animal, of course, a heart is fairly obviously a heart when it has been dissected sufficiently to show its valve structure. A four-kilogram copper nugget had come from the factory section; the organism had at least started to fulfill its intended purpose before disease had ended its pseudolife. It had also been developing normally in other respects, as a twenty-five-centimeter embryo indicated. The zeowhales and their kindred devices reproduced asexually; the genetic variation magnification, which is the biological advantage of sex, was just what the users of the pseudo-organisms did not want, at least until some factor could be developed which would tend to select for the characteristics they wanted most. 

Mancini spent more than an hour at his rather revolting task before he finally laid down his instruments. Stubbs had not been able to watch him the whole time, since the Shark had picked up the other two unresponsive whales while the job was going on. Both had been infected in the same way as the first. The boy was back in the lab, though, when the gross dissection of the original one was finished. So was Winkle, since nothing more could be planned until Mancini produced some sort of report. 

"The skeleton was gone completely," was the mechanic's terse beginning. "Even the unborn one hadn't a trace of metallic iron in it. That was why the magnets didn't hold, of course. I haven't had time to look at any of the analysis reports, but I'm pretty certain that the jelly in the body cavity and the moldy stuff outside are part of the same life form, and that organism dissolved the metallic skeleton and precipitated the iron as magnetite in its own tissues. Presumably it's a mutant from one of the regular iron-feeding strains. Judging by its general cellular conformation, its genetic tape is a purine-pyrimidine nucleotide quite similar to that of natural life—" 

"Just another of the original artificial forms coming home to roost?" interjected Winkle. 

"I suppose so. I've isolated some of the nuclear material, but it will have to go back to the big field analyzer on the Guppy to make sure."

"There seem to be no more damaged fish in the neighborhood. Is there any other material you need before we go back?" 

"No. Might as well wind her up, as far as I'm concerned—unless it would be a good idea to call the ship first while we're out here to find out whether any other schools this way need checking." 

"You can't carry any more specimens in your lab even if they do," Winkle pointed out, glancing around the littered bench tops. 

"True enough. Maybe there's something which wouldn't need a major checkup, though. But you're the captain; play it as you think best. I'll be busy with this lot until we get back to the Guppy whether we go straight there or not." 

"I'll call." The captain turned away to his own station. 

"I wonder why they made the first pseudolife machines with gene tapes so much like the real thing," Stubbs remarked when Winkle was back in his seat. "You'd think they'd foresee what mutations could do, and that organisms too similar to genuine life might even give rise to forms which could cause disease in us as well as in other artificial forms." 

"They thought of it, all right," replied Mancini. "That possibility was a favorite theme of the opponents of the whole process—at least, of the ones who weren't driven by frankly religious motives. Unfortunately, there was no other way the business could have developed. The original research of course had to be carried out on what you call 'real' life. That led to the specific knowledge that the cytosine-thiamine-adenine-guanine foursome of ordinary DNA could form a pattern which was both self-replicating and able to control polypeptide and polysaccharide synthesis—" 

"But I thought it was more complex than that; there are phosphates and sugars in the chain, and the DNA imprints RNA, and—" 

"You're quite right, but I wasn't giving a chemistry lecture; I was trying to make an historical point. I'm saying that at first, no one realized that anything except those four specific bases could do the genetic job. Then they found that quite a lot of natural life forms had variations of those bases in their nucleotides, and gradually the reasons why those structures, or rather their potential fields, had the polymer molding ability they do became clear. Then, and only then, was it obvious that 'natural' genes aren't the only possible ones; they're simply the ones which got a head start on this planet. There are as many ways of building a gene as there are of writing a poem—or of making an airplane if you prefer to stay on the physical plane. As you seem to know, using the channels of a synthetic zeolite as the backbone for a genetic tape happens to be a very convenient technique when we want to grow a machine like the one we've just taken apart here. It's bulkier than the phosphate-sugar-base tape, but a good deal more stable. 

"It's still handy, though, to know how to work with the real thing—after all, you know as well as I do that the reason you have a life expectancy of about a hundred and fifty years is that your particular gene pattern is on file in half a cubic meter of zeolite mesh in Denver under a nice file number..." 

"026-18-5633," muttered the boy under his breath. 

"...which will let any halfway competent molecular mechanic like me grow replacement parts and tissues if and when you happen to need them." 

"I know all that, but it still seems dangerous to poke around making little changes in ordinary life forms," replied Rick. "There must be fifty thousand people like you in the world, who could tailor a dangerous virus, or germ, or crop fungus in a couple of weeks of lab and computer work, and whose regular activities produce things like that iron-feeder which can mutate into dangerous by-products." 

"It's also dangerous to have seven billion people on the planet, practically every one of whom knows how to light a fire," replied Mancini. "Dangerous or not, it was no more possible to go from Watson and Crick and the DNA structure to this zeowhale without the intermediate development than it would have been to get from the Wright brothers and their powered kite to the two-hour transatlantic ramjet without building Ford tri-motors and DC-3's in between. We have the knowledge, it's an historical fact that no one can effectively destroy it, so we might as well use it. The fact that so many competent practitioners of the art exist is our best safeguard if it does get a little out of hand at times." 

The boy looked thoughtful. 

"Maybe you have something there," he said slowly. "But with all that knowledge, why only a hundred and fifty years? Why can't you keep people going indefinitely?" 

"Do you think we should?" Mancini countered with a straight face. Rick grinned. 

"Stop ducking. If you could, you would—for some people anyway. Why can't you?" Mancini shrugged. 

"Several hundred million people undoubtedly know the rules of chess." He nodded toward the board on Dandridge's control table. "Why aren't they all good players? You know, don't you, why doctors were reluctant to use hormones as therapeutic agents even when they became available in quantity?" 

"I think so. If you gave someone cortisone it might do what you wanted, but it might also set other glands going or slow them down, which would alter the levels of other hormones, which in turn...well, it was a sort of chain reaction which could end anywhere." 

"Precisely. And gene-juggling is the same only more so. If you were to sit at the edge of the hatch there and let Gil close it on you, I could rig the factors in your gene pattern so as to let you grow new legs; but there would be a distinct risk of affecting other things in your system at the same time. In effect, I would be taking certain restraints which caused your legs to stop growing when they were completed off your cell-dividing control mechanisms—the sort of thing that used to happen as a natural, random effect in cancer. I'd probably get away with it—or rather, you would—since you're only about nineteen and still pretty deep in what we call the stability well. As you get older, though, with more and more factors interfering with that stability, the job gets harder—it's a literal juggling act, with more and more balls being tossed to the juggler every year you live. 

"You were born with a deep enough stability reserve to keep yourself operating for a few decades without any applied biochemical knowledge; you might live twenty years or ninety. Using the knowledge we have, we can play the game longer; but sooner or later we drop the ball. It's not that we don't know the rules; to go back to the chess analogy, it's just that there are too many pieces on the board to keep track of all at once." 

Stubbs shook his head. "I've never thought of it quite that way. To me, it's always been just a repair job, and I couldn't see why it should be so difficult." 

Mancini grinned. "Maybe your cultural grounding didn't include a poem called the 'The Wonderful One-Hoss Shay.' Well, we'll be a couple of hours getting back to the Guppy. There are a couple of sets of analysis runs sitting with us here. Maybe, if I start trying to turn those into language you can follow, you'll have some idea of why the game is so hard before we get there, Maybe, too"—his face sobered somewhat—"you'll start to see why, even though we always lose in the end, the game is so much fun. It isn't just that our own lives are at stake, you know; men have been playing that kind of game for two million years or so. Come on." 

He turned to the bench top on which the various analyzers had been depositing their results; and since Stubbs had a good grounding in mathematical and chemical fundamentals, their language ceased to resemble Basic English. Neither paid any attention as the main driving turbines of the Shark came up to quarter speed and the vessel began to pick her way out of the patch of ice floes where the zeowhales had been collecting metal. 

By the time Winkle had reached open water and Ishihara had given him the clearance for high cruise, the other four had lost all contact with the outside world. Dandridge's chess board was in use again, with Farrell now his opponent. The molecular mechanic and his possible apprentice were deeply buried in a task roughly equivalent to explaining to a forty-piece orchestra how to produce Aida from overture to finale—without the use of written music. Stubbs' basic math was, for this problem, equivalent to having learned just barely his "do, re, mi." 

There was nothing to distract the players of either game. The wind had freshened somewhat, but the swells had increased little if at all. With the Shark riding on her hydrofoils there was only the faintest of tremors as her struts cut the waves. The sun was still high and the sky almost cloudless. Between visual pilotage and sonar, life seemed as uncomplicated as it ever gets for the operator of a high-speed vehicle. 

The Guppy was nearly two hundred kilometers to the south, far beyond sonar range. Four of her other boats were out on business, and Winkle occasionally passed a word or two with their commanders; but no one had anything of real importance to say. The desultory conversations were a matter of habit, to make sure that everyone was still on the air. No pilot, whether of aircraft, space vessel, surface ship, or submarine, attaches any weight to the proverb that no news is good news. 

Just who was to blame for the interruption of this idyll remains moot. Certainly Mancini had given the captain his preliminary ideas about the pest which had killed their first whale. Just as certainly he had failed to report the confirmation of that opinion after going through the lab results with Stubbs. Winkle himself made no request for such confirmation—there was no particular reason why he should, and if he had it is hard to believe that he would either have realized all the implications or been able to do anything about them. The fact remains that everyone from Winkle at the top of the ladder of command to Stubbs at the bottom was taken completely by surprise when the Shark's starboard after hydrofoil strut snapped cleanly off just below the mean planing water line. 

At sixty-five knots, no human reflexes could have coped with the result. The electronic ones of the Shark tried, but the vessel's mechanical I.Q. was not up to the task of allowing for the lost strut. As the gyros sensed the drop in the right rear quadrant of their field of perception, the autopilot issued commands to increase the angle of attack of the control foils on that strut. Naturally there was no response. The dip increased. By the time it got beyond the point where the machine thought it could be handled by a single set of foils, so that orders went out to decrease lift on the port-bow leg, it was much too late. The after portion of the starboard flotation hull smacked a wave top at sixty-five knots and, of course, bounced. The bounce was just in time to reinforce the letdown command to the port-bow control foils. The bow curve of the port hull struck in its turn, with almost undiminished speed and with two principal results. 

About a third of the Shark's forward speed vanished in less than the same fraction of a second as she gave up kinetic energy to the water in front, raising a cloud of spray more than a hundred meters and subjecting hull and contents to about four gravities of acceleration in a most unusual direction. The rebound was high enough to cause the starboard "wing" to dip into the waves, and the Shark did a complete double cartwheel. For a moment she seemed to poise motionless with port wing and hull entirely submerged and the opposite wing tip pointing at the sky; then, grudgingly, she settled back to a nearly horizontal position on her flotation hulls and lay rocking on the swell. 

Externally she showed little sign of damage. The missing strut was, of course, under water anyway, and her main structure had taken only a few dents. The propellers had been twisted off by gyroscopic action during the cartwheel. Aside from this, the sleek form looked ready for service. 

Inside, things were different, Most of the apparatus, and even some of the men, had been more or less firmly fixed in place; but the few exceptions had raised a good deal of mayhem. 

Winkle and Ishihara were unconscious, though still buckled in their seats. Both had been snapped forward against their respective panels, and were draped with sundry unappetizing fragments of the dissected zeowhale. Ishihara's head had shattered the screen of his sonar instrument, and no one could have told at first glance how many cuts were supplying the blood on his face. 

The chess players had both left impressions on the control panel of the winch and handling system, and now lay crumpled beside it. Neither was bleeding visibly, but Farrell's arms were both twisted at angles impossible to intact bones. Dandridge was moaning and just starting to try to get to his feet; he and Mancini were the only ones conscious. 

The mechanic had been seated at one of his benches facing the starboard side of the ship when the impact came. He had not been strapped in his seat, and the four-G jerk had started to hurl him toward the bow. His right leg had stopped him almost as suddenly by getting entangled in the underpinning of the seat The limb was not quite detached from its owner; oddly enough, its skin was intact. This was about the only bit of tissue below the knee for which this statement could he made.

Stubbs had been standing at the mechanic's side. They were to argue later whether it had been good or bad luck that the side in question had been the left. It depended largely on personal viewpoint. There had been nothing for Rick to seize as he was snatched toward the bow or, if there was, he had not been quick enough or strong enough to get it. He never knew just what hit him in flight; the motions of the Shark were so wild that it might have been deck, overhead, or the back of one of the pilot seats. It was evident enough that his path had intersected that of the big flask in which Mancini had first collected the iron-feeding tissue, but whether the flask was still whole at the time remains unclear. It is hard to see how he could have managed to absorb so many of its fragments had it already shattered, but it is equally hard to understand how he could have scattered them so widely over his anatomy if it had been whole. 

It was Stubbs, or rather the sight of him, that got Mancini moving. Getting his own shattered leg disentangled from the chair was a distracting task, but not distracting enough to let him take his eyes from the boy a few meters away. Arterial bleeding is a sight that tends to focus attention. 

He felt sick, over and above the pain of his leg; whether it was the sight of Rick or incipient shock he couldn't tell. He did his best to ignore the leg as he inched across the deck, though the limb itself seemed to have other ideas. Unfortunately these weren't very consistent; sometimes it wanted—demanded his whole mind, at others it seemed to have gone off somewhere on its own and hidden. He did not look back to see whether it was still with him; what was in front was more important. 

The boy still had blood when Mancini reached him, as well as a functioning heart to pump it. He was not losing the fluid as fast as had appeared from a distance, but something would obviously have to be done about what was left of his right hand—the thumb and about half of the palm. The mechanic had been raised during one of the periods when first-aiders were taught to abjure the tourniquet, but had reached an age where judgment stands a chance against rules. He had a belt and used it. 

A close look at the boy's other injuries showed that nothing could be done about them on the spot; they were bleeding slowly, but any sort of first aid would be complicated by the slivers of glass protruding from most of them. Face, chest, and even legs were slashed freely, but the rate of bleeding was not—Mancini hoped—really serious. The smaller ones were clotting already. 

Dandridge was on his feet by now, badly bruised but apparently in the best shape of the six. 

"What can I do, Marco?" he asked. "Everyone else is out cold. Should I use—" 

"Don't use anything on them until we're sure there are no broken necks or backs; they may be better off unconscious. I know I would be." 

"Isn't there dope in the first-aid kit? I could give you a shot of painkiller." 

"Not yet, anyway. Anything that would stop this leg from hurting would knock me out, and I've got to stay awake if at all possible until help comes. The lab equipment isn't really meant for repair work, but if anything needs to be improvised from it. I'll have to be the one to do it. 

I could move around better, though, if this leg were splinted. Use the raft foam from the handling locker." 

Five minutes later Mancini's leg, from mid-thigh down, was encased in a bulky, light, but reasonably rigid block of foamed resin whose original purpose was to provide on-the-spot flotation for objects which were inconvenient or impossible to bring aboard. It still hurt, but he could move around without much fear of doing the limb further damage. 

"Good. Now you'd better see what communication gear, if any, stood up under this bump. I'll do what I can for the others. Don't move Ishi or the captain; work around them until I've done what I can." 

Dandridge went forward to the conning section and began to manipulate switches. He was not a trained radioman—the Shark didn't carry one—but like any competent crew member he could operate all the vessel's equipment under routine conditions. He found quickly that no receivers were working, but that the regular transmitter drew current when its switches were closed. An emergency low-frequency beacon, entirely separate from the other communication equipment, also seemed intact; so he set this operating and began to broadcast the plight of the Shark on the regular transmitter. He had no way of telling whether either signal was getting out, but was not particularly worried for himself. The Shark was theoretically unsinkable—enough of her volume was filled with resin foam to buoy her entire weight even in fresh water. The main question was whether help would arrive before some of the injured men were beyond it. 

After ten minutes of steady broadcasting—he hoped—Dandridge turned back to the mechanic, to find him lying motionless on the deck. For a moment the winchman thought he might have lost consciousness; then Mancini spoke. 

"I've done all I can for the time being. I've splinted Joe's arms and pretty well stopped Rick's bleeding. Ishi has a skull fracture and the captain at least a concussion; don't move either one. If you've managed to get in touch with the Guppy, tell them about the injuries. We'll need gene records from Denver for Rick, probably for Ishi, and possibly for the captain. They should start making blood for Rick right away, the second enough gene data is through; he's lost quite a bit." 

"I don't know whether I'm getting out or not, but I'll say it all anyway," replied Dandridge, turning back to the board. "Won't you need some pretty extensive repair work yourself, though?" 

"Not unless these bone fragments do more nerve damage than I think they have," replied Mancini. "Just tell them that I have a multiple leg fracture. If I know Bert Jellinge, he'll have gene blocks on all six of us growing into the machines before we get back to the Guppy anyway." 

Dandridge eyed him more closely. "Hadn't I better give you a shot now?" he asked. "You said you'd done all you could, and it might be better to pass out from a sleepy shot than from pain. How about it?" 

"Get that message out first. I can hold on, and what I've done is the flimsiest of patchwork. With the deck tossing as it is any of those splints may be inadequate. We can't strap any of the fellows down, and if the wave motion rolls one of them over I'll have the patching to do all over again. When you get that call off, look at Rick once more; I think his bleeding has stopped, but until he's on a repair table I won't be happy about him." 

"So you'd rather stay awake." 

"Not exactly, but if you were in the kid's place, wouldn't you prefer me to?" Dandridge had no answer to that one; he talked into the transmitter instead. 

His words, as it happened, were getting out. The Conger, the nearest of the Shark's sister fish-tenders, had already started toward them; she had about forty kilometers to come. On the Guppy the senior mechanic had fulfilled Mancini's prediction; he had already made contract with Denver, and Rick Stubbs' gene code was about to start through the multiple-redundant communication channels used for the purpose—channels which, fortunately, had just been freed of the saturation caused by a serious explosion in Pittsburgh, which had left over five hundred people in need of major repair. The full transmission would take over an hour at the highest safe scanning rate; but the first ten minutes would give enough information, when combined with the basic human data already in the Guppy's computers, to permit the synthesis of replacement blood. 

The big mother-ship was heading toward the site of the accident so as to shorten the Conger's journey with the victims, The operations center at Cape Farewell had offered a "mastodon"—one of the gigantic helicopters capable of lifting the entire weight of a ship like the Shark. After a little slide-rule work, the Guppy's commander had declined; no time would have been saved, and the elimination of one ship-to-ship transfer for the injured men was probably less important than economy of minutes. 

Mancini would have agreed with this, had he been able to join in the discussion. By the time Dandridge had finished his second transmission, however, the mechanic had fainted from the pain of his leg. 

Objectively, the winchman supposed that it was probably good for his friend to be unconscious. He was not too happy, though, at being the only one aboard who could take responsibility for anything. The half hour it took for the Conger to arrive was not a restful one for him, though it could not have been less eventful. Even sixty years later, when the story as his grandchildren heard it included complications like a North Atlantic winter gale, he was never able to paint an adequate word picture of his feelings during those thirty minutes—much less an exaggerated one. 

The manta-like structure of the tenders made transshipping most practical from bow-to-bow contact, but it was practical at all only on a smooth sea. In the present case, the Conger's commander could not bring her bow closer than ten meters to that of the crippled ship, and both were pitching too heavily even for lines to be used. 

One of the Conger's divers plunged into the water and swam to the helpless vessel. Dandridge saw him coming through the bow ports, went back to his console, and rather to his surprise found that the hatch and ladder responded to their control switches. Moments later the other man was on the deck beside him. 

The diver took in the situation after ten seconds of explanation by Dandridge and two of direct examination, and spoke into the transmitter which was part of his equipment. A few seconds later a raft dropped from the Conger's hatch and two more men clambered down into it. One of these proved on arrival to be Mancini's opposite number, who wasted no time. 

"Use the foam," he directed. "Case them all up except for faces; that way we can get them to the bench without any more limb motion. You say Marco thought there might be skull or spine fractures?" 

"He said Ishi had a fractured skull and Winkle might have. All he said about spines was that we'd have to be careful in case it had happened." 

"Right. You relax; I'll take care of it." The newcomer took up the foam generator and went to work. 

Twenty minutes later the Conger was on her hydroplanes once more, heading for rendezvous with the Guppy. 

In spite of tradition, Rick Stubbs knew where he was when he opened his eyes. The catch was that he hadn't the faintest idea how he had gotten there. He could see that he was surrounded by blood-transfusion equip- ment, electronic circulatory and nervous system monitoring gear, and the needle-capillary-and-computer maze of a regeneration unit, though none of the stuff seemed to be in operation. He was willing to grant from all this that he had been hurt somehow; the fact that he was unable to move his head or his right arm supported this notion. He couldn't begin to guess, however, what sort of injury it might be or how it had happened. He remembered talking and working with Mancini at the latter's lab bench. He could not recall for certain just what the last thing said or done might be, though; somehow the picture merged with the foggy struggle back to consciousness which had culminated in recognition of his surroundings. 

He could see no one near him, but this might be because his head wouldn't turn. Could he talk? Only one way to find out. 

"Is anyone here? What's happened to me?" It didn't sound very much like his own voice, and the effort of speech hurt his chest and abdomen; but apparently words got out. 

"We're all here, Rick. I thought you'd be switching back on about now." Mancini's face appeared in Stubbs' narrow field of vision. 

"We're all here? Did everyone get hurt somehow? What happened?" 

"Slight correction—most of us are here, one's been and gone. I'll tell you as much as I can; don't bother to ask questions, I know it must hurt you to talk. Gil was here for a while, but he just had a few bruises and is back on the job. The rest of us were banged up more thoroughly. My right leg was a jigsaw puzzle; Bert had an interesting time with it. I thought he ought to take it off and start over, but he stuck with it, so I got off with five hours of manual repair and two in regeneration instead of a couple of months hooked up to a computer. I'm still splinted, but that will be for only a few more days. 

"No one knows yet just what happened. Apparently the Shark hit something going at full clip, but no one knows yet what it was. They're towing her in; I trust there'll be enough evidence to tell us the whole story." 

"How about the other fellows?" 

"Ishi is plugged in. He may need a week with computer regeneration control, or ten times that. We won't be able to assess brain damage until we find how close to consciousness he can come. He had a bad skull fracture. The captain was knocked out, and some broken ribs I missed on the first-aid check did internal damage. Bert is still trying to get him off without regeneration, but I don't think he'll manage it." 

"You didn't think he could manage it with you, either." 

"True. Maybe it's just that I don't think I could do it myself, and hate to admit that Jellinge is better at my own job than I am." 

"How about Joe?" 

"Both arms broken and a lot of bruises. He'll he all right. That leaves you, young fellow. You're not exactly a critical case, but you are certainly going to call for professional competence. How fond are you of your fingerprints?" 

"What? I don't track." 

"Most of your right hand was sliced off, apparently by flying glass from my big culture flask. Ben Tulley from the Conger, which picked us up, found the missing section and brought it back; it's in culture now." 

"What has that to do with fingerprints? Why didn't you or Mr. Jellinge graft it back?" 

"Because there's a good deal of doubt about its condition. It was well over an hour after the accident before it got into culture. You know the sort of brain damage a few minutes without oxygen can do. I know the bone, tendon, and connective tissue in a limb is much less sensitive to that sort of damage, but an hour is a long time, chemically speaking. Grafting calls for healing powers which are nearly as dependent on genetic integrity as is nerve activity; we're just not sure whether grafting is the right thing to do in your case. It's a toss-up whether we should fasten the hand back on and work to make it take, or discard it and grow you a new one. That's why I asked how much you loved your fingerprints." 

"Wouldn't a new hand have the same prints?" 

"The same print classification, which is determined genetically, but not the same details, which are random." 

"Which would take longer?" 

"If the hand is in shape to take properly, grafting would be quicker—say a week. If it isn't, we might be six or eight times as long repairing secondary damage. That's longer than complete regeneration would take." 

"When are you going to make up your minds?" 

"Soon. I wondered whether you'd have a preference." 

"How could I know which is better when you don't? Why ask me at all?" 

"I had a reason—several, in fact. I'll tell you what they were after you've had two years of professional training in molecular mechanics, if you decide to come into the field. You still haven't told me which you prefer." 

The boy looked up silently for a full minute. Actually, he spent very little of that time trying to make his mind up; he was wondering what Mancini's reasons might be. He gave up, flipped a mental coin, and said, "I think I'd prefer the original hand, if there's a real chance of getting it back and it won't keep me plugged in to these machines any longer than growing a new one would." 

"All right, we'll try it that way. Of course, you'll be plugged in for quite a while anyway, so if we do have trouble with the hand it won't make so much difference with your time." 

"What do you mean? What's wrong besides the hand?" 

"You hadn't noticed that your head is clamped?" 

"Well, yes; I knew I couldn't move it, but I can't feel anything wrong. What's happened there?" 

"Your face stopped most of the rest of the flask, apparently." 

"Then how can I be seeing at all, and how is it that I talk so easily?" 

"If I knew that much about probability, I'd stop working for a living and take up professional gambling. When I first saw you after your face had been cleaned off and before the glass had been taken out, I wondered for a moment whether there hadn't been something planned about the arrangement of the slivers. It was unbelievable, but that's the way it happened. They say anything can happen once, but I'd advise you not to catch any more articles of glassware with your face," 

"Just what was it like, Marco? Give me the details." 

"Frankly, I'd rather not. There are record photos, of course, but if I have anything to say about it you won't see them until the rebuilding is done. Then you can look in a mirror to reassure yourself when the photos get your stomach. No"—as Stubbs tried to interrupt—"I respect what you probably think of as your clinical detachment, but I doubt very strongly that you could maintain it in the face of the real thing. I'm pretty sure that I couldn't, if it were my face." Mancini's thoughts flashed back to the long moments when he had been dragging his ruined leg across the Shark's deck toward the bleeding boy, and felt a momentary glow—maybe that disclaimer had been a little too modest. He stuck to his position, however. 

Rick didn't argue too hard, for another thought had suddenly struck his mind. "You're using regeneration on my face, without asking me whether I want it the way you did with my hand. Right?" 

"That's right," Mancini said. 

"That means I'm so badly damaged that ordinary healing won't take care of it," 

Mancini pursed his lips and thought carefully before answering. "You'd heal, all right," he admitted at last. "You might just possibly, considering your age, heal without too much scarring. I'd hesitate to bet on that, though, and the scars you could come up with would leave you quite a mess." 

Stubbs lay silent for a time, staring at the featureless ceiling. The mechanic was sure his expression would have been thoughtful had enough of the young face been visible to make one. He could not, however, guess at what was bothering the boy. As far as Mancini could guess from their work together there was no question of personal cowardice—for that matter, the mechanic could not see what there might be to fear. His profession made him quite casual about growing tissue, natural or artificial, on human bodies or anywhere else. Stubbs was in no danger of permanent disfigurement, crippling damage, or even severe pain; but something was obviously bothering the kid, 

"Marco," the question came finally, "just where does detailed genetic control end, in tissue growth, and statistical effects take over?" 

"There's no way to answer that both exactly and generally. Genetic factors are basically probability ones, but they're characterized by regions of high probability which we call stability wells. I told you about fingerprints, but each different situation would call for a different specific answer." 

"It was what you said about prints that made me think of it. You're going to rebuild my face, you say. You won't tell me just how much rebuilding has to be done, but you admitted I could heal normally. If you rebuild, how closely will you match my original face? Does that statistical factor of yours take over somewhere along the line?" 

"Statistical factors are everywhere, and work throughout the whole process," replied Mancini without in the least meaning to be evasive. "I told you that. By rights, your new face should match the old as closely as the faces of identical twins match each other, and for the same reason. I grant that someone who knows the twins really well can usually tell them apart, but no one will have your old face around for close comparison. No one will have any doubt that it's you, I promise." 

"Unless something goes wrong." 

"If it goes wrong enough to bother you, we can always do it over." "But it might go really wrong." 

Mancini, who would have admitted that the sun might not rise the next day if enough possible events all happened at once, did not deny this, though he was beginning to feel irritated. "Does this mean that you don't want us to do the job? Just take your chances on the scars?" he asked. 

"Why do scars form, anyway?" was the counter. "Why can't regular, normal genetic material reproduce the tissue it produced in the first place? It certainly does sometimes; why not always?" 

"That's pretty hard to explain in words. It has to do with the factors which stopped your nose growing before it became an elephant's trunk—or more accurately, with the factors which stopped your overall growth where they did. I can describe them quite completely, and I believe quite accurately, but not in Basic English." 

"Can you measure those factors in a particular ease?" 

"Hm-m-m, yes; fairly accurately, anyway." Stubbs pounced on this with an eagerness which should have told the mechanic something. 

"Then can't you tell whether these injuries, in my particular case, will heal completely or leave sears?" 

"I...well, I suppose so. Let's see; it would take...hm-m-m; I'll have to give it some thought. It's not regular technique. We usually just rebuild. What's your objection, anyway? All rebuilding really means is that we set things going and then watch the process, practically cell by cell, and correct what's happening if it isn't right—following the plans you used in the first place." 

"I still don't see why my body can't follow them without your help." 

"Well, no analogy is perfect; but roughly speaking, it's because the cells which will have to divide to produce the replacement tissue had the blueprints which they used for the original construction stamped 'production complete; file in reference storage' some years ago, and the stamp marks covered some of the lines on the plans." Mancini's temper was getting a little short, as his tone showed. Theoretically his leg should not have been hurting him, but he had been standing on it longer than any repairman would have advised at its present stage of healing. And why did the kid keep beating around the bush? 

Stubbs either didn't notice the tone or didn't care. 

"But the plans—the information—that's still there; even I know that much molecular biology. I haven't learned how to use your analysis gear yet, much less to reduce the readings; but I can't see why you'd figure it much harder to read the plans under the 'file' stamp than to work out the ability of that magnetite slime to digest iron from the base configuration of a single cell's genes." 

"Your question was why your body couldn't do it; don't change the rules in the middle of the game. I didn't say that I couldn't; I could. What I said was that it isn't usual, and I can't see what will be gained by it; you'd at least double the work. I'm not exactly lazy, but the work at best is difficult, precise, and time consuming. If someone were to paint your portrait and had asked you whether you wanted it on canvas or paper, would you dither along asking about the brand of paint and the sizes of brushes he was going to use. 

"I don't think that's a very good analogy. I just want to know what to expect—" 

"You can't know what to expect. No one can. Ever. You have to play the odds. At the moment, the odds are so high in your favor that you'd almost be justified in saying that you know what's going to happen. All I'm asking is that you tell me straight whether or not you want Bert and me to ride control as your face heals, or let it go its own way." 

"But if you can grow a vine that produces ham sandwiches instead of pumpkins, why—" Mancini made a gesture of impatience. He liked the youngster and still hoped to recruit him, but there are limits. 

"Will you stop sounding like an anti-vivisectionist who's been asked for a statement on heart surgery and give me a straight answer to a straight question? The chances are all I can give you. They are much less than fifty-fifty that your face will come out of this without scars on its own. They are much better than a hundred to one that even your mother will never know there's been a controlled regeneration job done on you unless you tell her. You're through general education, legally qualified to make decisions involving your own life and health, and morally obligated to make them instead of lying there dithering. Let's have an answer." 

For fully two minutes, he did not get it. Rick lay still, his expression hidden in dressings, eyes refusing to meet those of the man who stood by the repair table. Finally, however, he gave in. 

"All right, do your best. How long did you say it would take?" 

"I don't remember saying, but probably about two weeks for your face. You'll be able to enjoy using a mirror long before we get that hand unplugged, unless we're remarkably lucky with the graft." 

"When will you start?" 

"As soon as I've had some sleep. Your blood is back to normal, your general pattern is in the machine; there's nothing else to hold us up. What sort of books do you like?" 

"Huh?" 

"That head's going to be in a clamp for quite a while. You may or may not like reading, but the only direction you can look comfortably is straight up. Your left hand can work a remote control, and the tape reader can project on the ceiling. I can't think of anything else to occupy you. Do you want some refreshing light fiction, or shall I start you on Volume One of Garwood's Elementary Matrix Algebra for Biochemists?" 

A regeneration controller is a bulky machine, even though most of it has the delicacy and structural intricacy possible only to pseudolife—and, of course, to "real" life. Its sensors are smaller in diameter than human red blood cells, and there are literally millions of them. Injectors and samplers are only enough larger to take entire cells into their tubes, and these also exist in numbers which would make the device a hopeless one to construct mechanically. Its computer-controller occupies more than two cubic meters of molecular-scale "machinery" based on a synthetic zeolite framework. Mating the individual gene record needed for a particular job to the basic computer itself takes nearly a day—it would take a lifetime if the job had to be done manually, instead of persuading the two to "grow" together. 

Closing the gap between the optical microscope and the test tube, which was blanketed under the word "protoplasm" for so many decades, also blurred the boundary between such initially different fields as medicine and factory design. Marco Mancini and Bert Jellinge regarded themselves as mechanics; what they would have been called a few decades earlier is hard to say. Even at the time the two had been born, no ten Ph.D.'s could have supplied the information which now formed the grounding of their professional practice. 

When their preliminary work—the "prepping"—on Rick Stubbs was done, some five million sensing tendrils formed a beard on the boy's face, most of them entering the skin near the edges of the injured portions. Every five hundred or so of these formed a unit with a pair of larger tubes. The sensors kept the computer informed of the genetic patterns actually active from moment to moment in the healing tissue—or at least, a statistically significant number of them. Whenever that activity failed to match within narrow limits what the computer thought should be happening, one of the larger tubes ingested a single cell from the area in question and transferred it to a large incubator—"large" in the sense that it could be seen without a microscope—just outside Rick's skin. There the cell was cultured through five divisions, and some of the product cells analyzed more completely than they could be inside a human body. If all were well after all, which was quite possible because of the limitations of the small sensors, nothing more happened. 

If things were really not going according to plan, however, others of the new cells were modified. Active parts of their genetic material which should have been inert were incited, quiet parts which should have been active were activated. The repaired cells were cultivated for several more divisions; if they bred true, one or more of them was returned to the original site—or at least, to within a few microns of it. Cell division and tissue building went on according to the modified plan until some new discrepancy was detected. 

Most of this was, of course, automatic; too many millions of operations were going on simultaneously for detailed manual control. Nevertheless, Mancini and Jellinge were busy. Neither life nor pseudolife is infallible; mutations occur even in triply-redundant records. Computation errors occur even—or especially—in digital machines which must by their nature work by successive-approximation methods. It is much better to have a human operator, who knows his business, actually see that connective tissue instead of epidermis is being grown in one spot, or nerve instead of muscle cells in another. 

Hence, a random selection of cells, not only from areas which had aroused the computer's interest but from those where all was presumably going well, also traveled out through the tubes. These went farther than just to the incubators; they came out to a point where gross microscopic study of them by a human observer was possible. This went on twenty-four hours a day, the two mechanics chiefly concerned and four others of their profession taking two-hour shifts at the microscope. The number of man-hours involved in treating major bodily injury had gone up several orders of magnitude since the time when a sick man could get away with a bill for ten dollars from his doctor, plus possibly another for fifty from his undertaker. The tendrils and tubes farthest from the damaged tissue were constantly withdrawing, groping their way to the action front, and implanting themselves anew, guided by the same chemical clues which brought leukocytes to the same area. Early versions of the technique had involved complex methods of warding off or removing the crowd of white cells from the neighborhood; the present idea was to let them alone. They were good scavengers, and the controller could easily allow for the occasional one which was taken in by the samplers. 

So, as days crawled by, skin and fat and muscle and blood vessels, nerves and bones and tendons, gradually extended into their proper places in Stubbs' face and hand, The face, as Mancini had predicted, was done first; the severed hand had deteriorated so that most of its cells needed replacement, though it served as a useful guide. 

With his head out of the clamp, the boy fulfilled another of the mechanic's implied predictions. He asked for a mirror. The man had it waiting, and produced it with a grin; but the grin faded as he watched the boy turn his face this way and that, checking his appearance from every possible angle. He would have expected a girl to act that way; but why should this youngster? 

"Are you still the same fellow?" Mancini asked finally. "At least, you've kept your fingerprints." Rick put the mirror down. 

"Maybe I should have taken a new hand," he said. "With new prints I might have gotten away with a bank robbery, and cut short the time leading to my well-earned retired leisure." 

"Don't you believe it," returned Mancini grimly. "Your new prints would be on file along with your gene record and retinal pattern back in Denver before I could legally have unplugged you from the machine. I had to submit a written summary of this operation before I could start, even as it was. Forget about losing your legal identity and taking up crime." 

Stubbs shrugged. "I'm not really disappointed. How much longer before I can write a letter with this hand, though?" 

"About ten days; but why bother with a letter? You can talk to anyone you want; haven't your parents been on the 'visor every day?" 

"Yes. Say, did you ever find out what made the Shark pile up?" 

Mancini grimaced. "We did indeed. She got infected by the same growth that killed the zeowhale we first picked up. Did you by any chance run that fish into any part of the hull while you were attaching the sling?" 

Rick stared aghast. "My gosh, Yes, I did. I held it against one of the side hulls because it was so slippery...I'm sorry...I didn't know—" 

"Relax. Of course you didn't. Neither did I, then; and I never thought of the possibility later. One of the struts was weakened enough to fail at high cruise, though, and Newton's Laws did the rest." 

"But does that mean that the other ships are in danger? How about the Guppy here? Can anything be done?" 

"Oh, sure. It was done long ago. A virus for that growth was designed within a few weeks of its original escape; its gene structure is on file. The mutation is enough like the original to be susceptible to the virus. We've made up a supply of it, and will be sowing it around the area for the next few weeks wherever one of the tenders goes. But why change the subject, young fellow? Your folks have been phoning, because I couldn't help hearing their talk when I was on watch. Why all this burning need to write letters? I begin to smell the proverbial rat." 

He noticed with professional approval that the blush on Rick's face was quite uniform; evidently a good job had been done on the capillaries and their auxiliary nerves and muscles. "Give, son!" 

"It's ... it's not important," muttered the boy. 

"Not important...oh, I see. Not important enough to turn you into a dithering nincompoop at the possibility of having your handsome features changed slightly, or make you drop back to second-grade level when it came to the responsibility for making a simple decision. I see. Well, it doesn't matter; she'll probably do all the deciding for you." 

The blush burned deeper. "All right, Marco, don't sound like an ascetic; I know you aren't. Just do your job and get this hand fixed so I can write—at least there's still one form of communication you won't be unable to avoid overhearing while you're on watch." 

"What a sentence! Are you sure you really finished school? But it's all right, Rick—the hand will be back in service soon, and it shouldn't take you many weeks to learn to write with it again—" 

"What?" 

"It is a new set of nerves, remember. They're connected with the old ones higher up in your hand and arm, but even with the old hand as a guide they probably won't go to exactly the same places to make contact with touch transducers and the like. Things will feel different, and you'll have to learn to use a pen all over again." The boy stared at him in dismay. "But don't worry. I'll do my best, which is very good, and it will only be a few more weeks. One thing, though—don't call your letter-writing problem my business; I'm just a mechanic. If you're really in love, you'd better get in touch with a doctor."