Cora saw the white cell at almost the time Michaels did.

"Look," she cried in horror.

They stopped, turned to look back.

The white cell was tremendous. It was five times as large in diameter as the Proteus, perhaps larger; a mountain of milky, skinless, pulsing protoplasm in comparison to the individuals watching.

Its large, lobed nucleus, a milky shadow within its substance seemed to be a malevolent, irregular eye, and the shape of the whole creature altered and changed with every moment. A portion bulged toward the Proteus.

Grant started toward the Proteus, almost as though by reflex action.

Cora seized his arm. "What are you going to do, Grant?"

Duval said, excitedly, "There's no way to save him. You'll be throwing away your life."

Grant shook his head violently, "It's not he I'm thinking of. It's the ship."

Owens said, sadly, "You can't save the ship, either."

"But we might be able to get it out, where it can expand safely. -Listen, even if it is crushed by the white cell; even if it is separated into atoms, each miniaturized atom will de-miniaturize; it is de-miniaturizing right now. It doesn't matter whether Benes is killed by an intact ship or by a pile of splinters."

Cora said, "You can't get the ship out. Oh, Grant, don't die. Not after all this. Please."

Grant smiled at her. "Believe me, I have every reason not to die, Cora. You three keep on going. Let me make just one college try."

He swam back, heart beating in an almost unbearable revulsion at the monster he was approaching. There were others behind it, farther off, but he wanted this one; the one that was engulfing the Proteus, only this one.

At closer quarters, he could see its surface; a portion in profile showed clear, but within were granules and vacuoles, an intricate mechanism, too intricate for biologists to understand in detail even yet, and all crammed into a single microscopic blob of living matter.

The Proteus was entirely within it now; a splintering dark shadow encased in a vacuole. Grant had thought that for a moment he had seen Michaels' face in the bubble but that might have been only imagination.

Grant was at the heaving mountainous surface now, but how was he to attract the attention of such a thing? It had neither eyes nor sense; neither a mind nor purpose.

It was an automatic machine of protoplasm designed to respond in certain fashion to injury.

How? Grant didn't know. Yet a white cell could tell when a bacterium was in its vicinity. In some cellular way, it knew. It had known when the Proteus was near it and it had reacted by engulfing it.

Grant was far smaller than the Proteus, far smaller than a bacterium, even now. Was he large enough to be noticed?

He had his knife out and sank it deeply into the material before him, slitting it downward.

Nothing happened. No gush of blood, for there is no blood in a white cell.

Then, slowly, a bulging of the inner protoplasm appeared at the site of the ruptured membrane and that portion of the membrane drew away.

Grant struck again. He didn't want to kill it; he didn't think he could at his present size. But was there some way of attracting its attention.

He drifted off and, with mounting excitement, noticed a bulge in the wall, a bulge pointing toward him.

He drifted further away and the bulge followed.

He had been noticed. The manner of the noticing he could not say, but the white cell with everything it contained, with the Proteus, was following.

He moved away faster now. The white cell followed but (Grant hoped fervently) not quickly. Grant had reasoned that it was not designed for speed; that it moved like an amoeba, bulging out a portion of its substance and then pouring itself into the bulge. Under ordinary conditions it fought with immobile objects, with bacteria and with foreign inanimate detritus. Its amoeboid motion was fast enough for that.

Now it would have to deal with an object capable of darting away.

(Darting away quickly enough, Grant hoped.)

With gathering speed, he swam toward the others who were still delaying, still watching for him.

He gasped, "Get a move on. I think it's following."

"So are others," said Duval, grimly.

Grant looked about. The distance was swarming with white cells. What one had noticed, all had noticed.

"How..."

Duval said, "I saw you strike at the white cell. If you damaged it, chemicals were released into the blood-stream; chemicals that attracted white cells from all the neighboring regions."

"Then, for God's sake, swim!"

The surgical team was gathered round Benes' head, while Carter and Reid watched from above. Carter's mood of black depression was deepening by the moment.

It was over. All for nothing. All for nothing. All for ... "

"General Carter! Sir!" The sound was urgent, strident. The man's voice was cracking with excitement.

"Yes?"

"The Proteus, sir. It's moving."

Carter yelled. "Stop surgery!"

Each member of the surgical team looked up in startled wonder.

Reid plucked at Carter's sleeve. "The motion may be the mere effect of the ship's slowly accelerating de-miniaturization. If you don't get them now, they will be in danger of the white cells."

"What kind of motion?" shouted Carter. "Where's it heading?"

"Along the optic nerve, sir."

Carter turned fiercely on Reid. "Where does that go? What does it mean?"

Reid's face lit up, "It means an emergency exit I hadn't thought of. They're heading for the eye and out through the lachrymal duct. They may make it. They might just get away with it, damaging one eye at most. Get a microscope slide, someone. Carter, let's get down there."

The optic nerve was a bundle of fibers, each like a string of sausages.

Duval paused to place his hand on the junction between two of the "sausages."

"A node of Ranvier," he said, wonderingly, "I'm touching it."

"Don't keep on touching it," gasped Grant. "Keep on swimming."

The white cells had to negotiate the close-packed network and did it less easily than the swimmers could. They had squeezed out into the interstitial fluid and were bulging through the spaces between the close-knit nerve fibers.

Grant watched anxiously to make sure that the white cell was still in pursuit. The one with the Proteus in it. He could not make out the Proteus any longer. If it existed in the white cell nearest, it had been transferred so deep into its substance that it was no longer visible. If the white cell behind was not the white cell, then Benes might be killed despite everything.

The nerves sparked wherever the beam from the helmet-lights struck and the sparkles moved backward in rapid progression.

"Light impulses," muttered Duval. "Genes' eyes aren't entirely closed."

Owens said, "Everything's definitely getting smaller. Do you notice that?"

Grant nodded. "I sure do." The white cell was only half the monster it had been only moments before; if that. "We only have seconds to go," said Duval.

Cora said "I can't keep up."

Grant veered toward her. "Sure you can. We're in the eye now. We're only the width of a tear-drop from safety." He put his arms around her waist, pushing her forward, then took the laser and its power-unit from her.

Duval said. "Through here and we'll be in the lachrymal duct."

They were large enough almost to fill the interstitial space through which they were swimming. As they grew, their speed had increased and the white cells grew less fearsome.

Duval kicked open the membranous wall be had come up against. "Get through," he said, "Miss Peterson, you first."

Grant pushed her through, and followed her. Then Owens and finally Duval.

"We're out," said Duval with a controlled excitement. "We're out of the body."

"Wait," said Grant. "I want that white cell out, too. Otherwise . . ."

He waited a moment, then let out a shout of excitement. "There it is. And, by heaven, it's the right one."

The white cell oozed through the opening that Duval's boot had made, but with difficulty. The Proteus, or the shattered splinters of it, could be seen clearly through its substance. It had expanded until it was nearly half the size of the white cell and the poor monster was finding itself with an unexpected attack of indigestion.

It struggled on gamely, however. Once it had been stimulated to follow, it could do nothing else.

The three men and a woman drifted upward in a well of rising fluid. The white cell, barely moving, drifted up with them.

The smooth curved wall at one side was transparent. It was transparent not in the fashion of the thin capillary wall, but truly transparent. There were no signs of cell membranes of nuclei.

Duval said, "This is the cornea. The other wall is the lower eyelid. We've got to get far enough away to deminiaturize fully without hurting Benes, and we only have seconds to do it in."

Up above, many feet above (on their still tiny scale) was a horizontal crack.

"Through there," said Duval.

"The ship's on the surface of the eye," came the triumphant shout.

"All right," said Reid. "Right eye."

A technician leaned close with the microscope slide at Benes' closed eye. A magnifying lens was in place. Slowly, with a felted clamp, the lower eyelid was gently pinched and pulled down.

"It's there,". said the technician in hushed tones. "Like a speck of dirt."

Skillfully, he placed the slide to the eye and a tear-drop with the speck in it squeezed on to it.

Everyone backed away.

Reid said, "Something that is large enough to see is going to get much larger very quickly. Scatter!"

The technician, torn between hurry and the necessity for gentleness, placed the slide down on the floor of the room,, then backed away at a quick trot.

The nurses wheeled the operating table quickly through the large double-door and with a startlingly accelerated speed, the specks on the slide grew to full size.

Three men, a woman, and a heap of metal fragments, rounded and eroded, were present where none had been a moment before.

Reid muttered, "Eight seconds to spare."

But Carter said, "Where's Michaels? If Michaels is still in Benes . . ." He started after the vanished operating table with the consciousness of defeat once again filling him.

Grant pulled off his helmet and waved him back. "It's all right, general. That's what's left of the Proteus and somewhere in it you'll find whatever's left of Michaels. Maybe just an organic jelly with some fragments of bones."

Grant still hadn't grown used to the world as it was. He had slept, with a few breaks, for fifteen hours, and he woke in wonder at a world of light and space.

He had breakfast in bed, with Carter and Reid at his bedside, smiling.

Grant said "Are the rest getting this treatment, too?"

Carter said, "Everything that money can buy-for a while, anyway. Owens is the only one we've let go. He wanted to be with his wife and kids and we turned him loose, but only after he gave us a quick description of what happened. -Apparently, Grant, the mission's success was more to your credit than to anyone's."

"If you want to go by a few items, maybe," said Grant. "If you want to recommend me for a medal and a promotion, I'll accept. If you want to recommend me for a year's vacation with pay, I'll accept them even more quickly. Actually, though, the mission would have been a failure without any one of us. Even Michaels guided us efficiently enough-for the most part."

"Michaels," said Carter, thoughtfully. "That bit about him, you know, isn't for publication. The official story is that he died in the line of duty. It wouldn't do any good to have it known that a traitor had infiltrated the CMDF. And I don't know that he was a traitor at that."

Reid said, "I knew him well enough to be able to say that he wasn't. Not in the usual sense of the word."

Grant nodded. "I agree. He wasn't a story-book villain. He took time to put a swim-suit on Owens before pushing him out of the ship. He was content to have the white cells kill Owens, but he couldn't do the job himself. No-I think he really wanted to keep indefinite miniaturization a secret for, as he saw it, the good of humanity."

Reid said, "He was all for peaceful uses of miniaturization. So am I. But what good would it do to ... "

Carter interrupted. "You're dealing with a mind that grew irrational under pressure. Look, we've had this sort of thing since the invention of the atomic bomb. There are always people who think that if some new discovery with frightful implications is suppressed, all will be well. Except that you can't suppress a discovery whose time has come. If Benes had died, indefinite miniaturization would still have been discovered next year, or five years from now, or ten. Only then, They might have had it first."

"And now We will have it first," said Grant, "and what do we do with it? End in the final war. Maybe Michaels was right."

Carter said, dryly, "And maybe the common sense of humanity will prevail on both sides. It has so far."

Reid said, "Especially since, once this story gets out, and the news media spread the tale of the fantastic voyage of the Proteus, the peaceful uses of miniaturization will he dramatized to the point where we can all fight military domination of the technique. And perhaps successfully."

Carter, taking out a cigar, looked grim and did not answer directly. He said, "Tell me, Grant, how did you catch on to Michaels?"

"I didn't really," said Grant. "It was all the result of a confused mass of thinking. In the first place, general, you put me on board ship because you suspected Duval."

"Oh, now-wait . . ."

"Everyone on the ship knew you had done so. Except Duval, perhaps. That gave me a headstart-in the wrong direction. However, you were clearly not sure of your ground, for you didn't warn me of anything, so I wasn't inclined to go off half-cocked myself. Those were high-powered people on board ship and I knew that if I grabbed someone and turned out to be mistaken, you would back off and let me take the rap."

Reid smiled gently, and Carter flushed and grew very interested in his cigar.

Grant said, "No hard - feelings, of course. It's part of my job to take the rap - but only if I have to. So I waited until I was sure, and I was never really sure.

"We were plagued with a series of accidents, or what might possibly have been accidents. For instance, the laser was damaged and there was the chance that Miss Peterson had damaged it? But why in so clumsy a fashion? She knew a dozen ways of gimmicking the laser so that it would seem perfectly all right and yet not work properly. She could have arranged it so that Duval's aim would be off just enough to make it inevitable that he kill the nerve, or perhaps even Benes. A crudely damaged laser was either an accident, then, or the deliberate work of someone other than Miss Peterson.

"Then, too, my lifeline came loose in the lungs and I nearly died as a result. Duval was the logical suspect there, but it was he who suggested that the ship's headlight be shone into the gap, and that saved me. Why try to kill me and then act to save me? It doesn't make sense. Either that was an accident, too, or my lifeline had been loosened by someone other than Duval.

"We lost our air-supply, and Owens might have arranged that little disaster. But then when we pulled in more air, Owens improvised an air-miniaturization device that seemed to, do miracles. He could easily not have done so and no one of us would have been able to accuse him of sabotage. Why bother to lose our air and then work like the devil to gain it back? Either that was an accident, too, or the air supply had been sabotaged by someone other than Owens.

"I could omit myself from consideration, since I knew that I wasn't engaged in sabotage. That left Michaels. "

Carter said, "You reasoned that he had been responsible for all those accidents."

"No, they might still have been accidents. We'll never know. But if it were sabotage then Michaels was far and away the most likely candidate for he was the only one who was not involved in a last-minute rescue, or who might be expected to have performed a more subtle piece of sabotage. So now let's consider Michaels.

"The first accident was the encounter with the arterio-venous fistula. Either that was an honest misfortune or Michaels had guided us into it deliberately. If this was sabotage, then unlike all the other cases, only one culprit was conceivable, only one - Michaels. He admitted as much himself at one point. Only he could possibly have guided us into it; only he could possibly know Benes' circulatory system well enough to spot a microscopic fistula; and it was he who directed the exact spot of insertion into the artery in the first place."

Reid said, "It might still have been a misfortune; an honest error."

"True! But whereas in all the other accidents, those who were involved as possible suspects did their best to pull us through, Michaels, after we had emerged into the venous system, argued hard for immediate abandonment of the mission. He did the same at every other crisis. He was the only one to do so consistently. And yet that wasn't the real giveaway as far as I was concerned."

"Well, then, what was the giveaway?" asked Carter.

"When the mission first started and we were miniaturized and inserted into the carotid artery, I was scared. We were all a little uneasy, to say the least, but Michaels was the most frightened of all. He was almost paralyzed with fear. I accepted that at the time. I saw no disgrace in it. As I said, I was pretty frightened myself, and in fact, I was glad of the company. But ... "

"But?"

"But after we had gotten through the arterio-venous fistula, Michaels never showed any trace of fear again. At times when the rest of us were nervous, he was not. He had become a rock. In fact, at the start, he had given me plenty of statements on what a coward he was-to explain his obvious fear-but toward the end of the voyage, he was offended almost to frenzy when Duval implied he wits a coward. That change in attitude got to seeming queerer and queerer to me.

"It seemed to me there had to be a special reason for his initial fear. As long as he faced dangers with the rest of us, he was a brave man. Perhaps, then, it was when he faced a danger the rest of us did not share that he was afraid. The inability to share the risk, the necessity to face death alone, was what turned him coward.

"At the start, after all, the rest of us were frightened of the mere act of being miniaturized but that was carried through safely. After that, we all expected to move toward the clot, operate on it and get out, taking ten minutes perhaps, all told.

"But Michaels must have been the only one of us who knew this was not going to happen. He alone must have known there would be trouble and that we were about to rumble into a whirlpool. Owens had spoken about the ship's fragility at the briefing and Michaels must have expected death. He alone must have expected death. No wonder he nearly broke down.

"When we got through the fistula in one piece, he was almost delirious with relief. After that, he felt certain that we would not be able to complete the mission and he relaxed. With each successful surmounting of some crisis, he grew angrier. He had no more room for fear, only for anger.

"By the time we were in the ear, I had made up my mind that Michaels, not Duval, was our man. I wouldn't let him badger Duval into trying the laser beforehand. I ordered him away from Miss Peterson when I was trying to get her away from the antibodies. But then in the end, I made a mistake. I didn't stay with him during the actual operation and thus gave him his chance to seize the ship. There was this last little shred of doubt in my mind ..."

"That perhaps it was Duval after all?" said Carter.

"I'm afraid so. So I went out to watch the operation when I could have done nothing about it even if Duval were a traitor. If it hadn't been for that final piece of stupidity, I might have brought the ship back intact, and Michaels alive."

"Well," Carter got to his feet, "It was cheap at the price. Benes is alive and slowly recovering. I'm not sure that Owens thinks so, though. He's in mourning for his ship."

"I don't blame him," said Grant, "it was a sweet vessel. Uh-listen, where's Miss Peterson, do you know?"

Reid said, "Up and around. She had more stamina than you had, apparently."

"I mean, is she here at the CMDF anywhere?"

"Yes. In Duval's office, I imagine."

"Oh," said Grant, suddenly deflated. "Well, I'll wash and shave and get out of here."

Cora put the papers together. "Well, then, Dr. Duval, if the report can wait over the weekend, I would appreciate the time off."

"Yes, certainly," said Duval. "I think we could all use some time off. How do you feel?"

"I seem to be all right."

"It's been an experience, hasn't it?"

Cora smiled and walked toward the door.

The corner of Grant's head pushed past it. "Miss Peterson?"

Cora started violently, recognized Grant, and came running to him, smiling. "It was Cora in the blood-stream." "Is it still Cora?"

"Of course. It always will be, I hope."

Grant hesitated. "You might call me Charles. You might even get to the point someday where you can call me Good Old Charlie."

"I'll try, Charles."

"When do you quit work?"

"I've just quit for the weekend."

Grant thought a while, rubbed his clean-shaven chin, then nodded toward Duval, who was bent over his desk. "Are you all tied up with him?" he asked at last.

Cora said, gravely, "I admire his work. He admires my work." And she shrugged.

Grant said, "May I admire you?"

She hesitated, then smiled a little. "Any time you want to. As long as you want to. If - if I can admire you occasionally, too."

"Let me know when and I'll strike a pose."

They laughed together. Duval looked up, saw them in the doorway, smiled faintly, and waved something that might have been either a greeting or a farewell.

Cora said, "I want to change into street clothes, and then I would like to see Benes. Is that all right?"

"Will they allow visitors?"

Cora shook her head. "No. But we're special."

Benes' eyes were open. He tried to smile.

A nurse whispered anxiously. "Only a minute, now. He doesn't know what's happened, so don't say anything about it."

"I understand," said Grant.

To Benes, in a low voice, he said, "How are you?"

Benes tried again to smile. "I'm not sure. Very tired. 1; have a headache and my right eye hurts, but I seem to, have survived."

"Good!"

"It takes more than a knock on the head to kill a scientist," said Benes. "All that mathematics makes the skull as hard as a rock, eh?"

"We're all glad of that," said Cora, gently.

"Now I must remember what I came here to tell. It's a little hazy, but it's coming back. It's all in me, all of it. And now he did smile.

And Grant said, "You'd be surprised at what's in you, professor."

The nurse ushered them out and Grant and Cora left, hand in warm hand, into a world that suddenly seemed to hold no terrors for them, but only the prospect of great joy.

The End