Carter lifted his coffee cup absently, Drops of liquid slipped off and landed on his pants leg. He noticed that but paid it no attention. "What do you mean, they've veered off."

"I should guess they felt they had spent too much time in the lymph node and didn't want to go through any more of them," said Reid.

"All right. Where are they going instead?"

"I'm not positive yet, but they seem to be headed for the inner ear. I'm not sure that I approve of that."

Carter put down his cup again and shoved it to one side. He had not placed it to his lips. "Why not?" He glanced quickly at the Time Recorder. It read 27.

"It will be difficult.' We'll have to watch out for sound."

"Why?"

"You can figure it out, can't you, Al? The ear reacts to sound. The cochlea vibrates. If the Proteus is anywhere near it, it will vibrate, too, and it may vibrate to destruction."

Carter leaned forward in his seat, staring at Reid's calm face. "Why are they going there, then?"

"I suppose because they think that's the only route that will get them to destination fast enough. Or, on the other hand, they may just be crazy. We have no way of telling since they cannibalized their wireless."

Carter said, "Are they in there yet? In the inner ear, I mean?"

Reid flicked a switch and asked a quick question. He turned back. "Just about."

Do the men down there in the operating room understand about the necessity for silence?"

"I suppose so."

"You suppose so. What good is supposing?"

"They won't be in it long."

"They'll be in it long enough. Listen, you tell those men down there . . . No, too late to take a chance. Get me a piece of paper and call in someone from outside. Anyone. Anyone."

An armed security man came in and saluted.

"Oh, shut up," said Carter, wearily. He didn't return the salute. He had scribbled on the paper in block letters: SILENCE! ABSOLUTE SILENCE WHILE PROTEUS IS IN EAR.

"Take this," he said to the security man. "You go down into the operating room and show it to each man. Make sure he looks at it. If you make any noise I'll kill you. If you say one word, I'll disembowel you first. Do you understand?"

"Yes, sir," he said, but looked confused and alarmed.

"Go ahead. Hurry.-And take off your shoes."

"Sir?"

"Take them off. You walk into that room on stocking feet."

They watched from the observation room, counting the interminable seconds until the stockinged soldier walked into the operating room. From doctor to nurse to doctor he went, holding up the paper and jerking a thumb up toward the control room. Person after person nodded grimly. None budged from his or her spot. For a moment, it seemed a mass paralysis had gripped everyone in the room.

"Obviously they understand," said Reid, "Even without instructions."

"I congratulate them," said Carter, savagely. "Now listen, you get in touch with the various guys at controls. No buzzers must sound, no bells, no gongs, nothing. For that matter, no flashing lights. I don't want anyone to be startled into as much as a grunt."

"They'll be through in a few seconds."

"Maybe," said Carter, "and maybe not. Hop to it."

Reid hopped to it.

The Proteus had entered a wide region of pure liquid. Except for a few antibodies flashing by now and then, there was nothing to be seen except the glitter of the ship's headlights making its way through the yellow-tinged lymph.

A dim sound below the threshold of hearing rubbed over the ship, almost as though it had slid against a washboard. Then again. And again.

Michaels called out, "Owens. Put out the cabin lights, will you?"

The exterior leaped into greater clarity at once. "Do you see that?" Michaels asked.

The others stared. Grant saw nothing at all.

"We're in the cochlear duct," said Michaels. "Inside the little spiral tube in the inner ear that does our hearing for us. This one does Benes' hearing for him. It vibrates to sound in different patterns. See?"

Now Grant saw. It was almost like a shadow in the fluid; a huge, flat shadow whipping past them.

"It's a sound wave," said Michaels. "At least, in a manner of speaking. A wave of compression which we somehow make out with our miniaturized light."

"Does that mean someone is talking?" asked Cora.

"Oh, no, if someone were talking or making any real sound, this thing would heave like the granddaddy of all earthquakes. Even in absolute silence, though, the cochlea picks up sounds; the distant thud of the heartbeat, the rasp of blood working through the tiny veins and arteries of the ear and so on. Didn't you ever cup your ear with a shell and listen to the sound of the ocean? What you're listening to mainly is the magnified sound of your own ocean, the blood-stream."

Grant said, "Will this be dangerous?"

Michaels shrugged. "No worse than it is -If no-one talks."

Duval, back in the work-room and bent over the laser once more, said, "Why are we slowing? Owens!"

Owens said, "Something's wrong. The engine is choking off and I don't know why."

There was the slowly intensifying sensation of being in a down-dropping elevator as the Proteus settled lower in the duct.

They hit bottom with a slight jar and Duval put down his scalpel. "Now what?"

Owens said anxiously. "The engine is overheating and I had to stop it. I think ..."

"What?"

"It must be those reticular fibers. The damned seaweed. It must have blocked the intake vents. There's nothing else I can think of that would be causing this."

"Can you blow them out?" asked Grant, tensely.

Owens shook his head. "Not a chance. Those are intake vents. They suck inward."

"Well, then, there's only one thing to do," said Grant. "It has to be cleaned off from the outside and that means more skin-diving." With furrowed brow, he began to clamber into his diving outfit.

Cora was looking anxiously out the window.

She said, "There are antibodies out there."

"Not many," said Grant, briefly.

"But what if they attack?"

"Not likely," said Michaels, reassuringly. "They're not sensitized to the human shape. And as long as no damage is done to the tissues themselves, the antibodies probably will remain passive."

"See," said Grant, but Cora shook her head.

Duval, who had listened for a moment, bent down to look at the wire he was shaving, matching it against the original wire thoughtfully, and then turning it in his hands slowly to try to gauge the evenness of its cross-section.

Grant dropped out the ventral hatch of the ship, landing on the soft-rubber elasticity of the lower wall of the cochlear duct. He looked ruefully at the ship. It was not the clean, smooth metal it had been. It looked furry, shaggy.

He kicked off into the lymph, propelling himself toward the bow of the ship. Owens was quite correct. The intake valves were choked with the fibers.

Grant seized a double handful and pulled. They came loose with difficulty, many breaking off at the surface of the vent filters.

Michaels' voice reached him over his small receiver. "How is it?"

"Pretty rotten," said Grant.

"How long will it take you? We've got a 26 reading on the Time Recorder."

"It's going to take me quite a while." Grant yanked desperately, but the viscosity of the lymph slowed his movements and the tenacity of the fibers seemed to fight back.

Within the ship, Cora said, tensely. "Wouldn't it be better if some of us went out to help him?"

"Well, now," began Michaels, doubtfully.

"I'm going to." She seized her suit.

Michaels said, "All right. I will, too. Owens had better stay at the controls."

Duval said, "And I think I had better stay right here, too. I have this thing almost done."

"Of course, Dr. Duval," said Cora. She adjusted her swimming mask.

The task was scarcely eased by the fact that three of them were soon wiggling about the ship's bow; all three snatching desperately at the fibers, pulling them loose, letting them drift away in the slow current. The metal of the filters was beginning to show and Grant pushed some recalcitrant pieces into the vent.

"I hope this doesn't do any harm, but I can't get them out. Owens, what if some of these fibers get into the vents; inside, I mean."

Owens voice in his ear said, "Then they get carbonized in the motor and foul it. It will mean a nasty cleaning job when we're through."

"Once we get through, I don't care if you have to scrap this stinking ship." Grant pushed at the fibers that were flush with the filters and pulled at those that weren't. Cora and Michaels did the same.

Cora said, "We're making it."

Michaels said, "But we're in the cochlea a lot longer than we had expected to be. At any moment, some sound ... "

"Shut up," said Grant irritably, "and finish the job."

Carter made as if to tear at his hair and then held back. "No, no, no, NO!" he cried. "They've stopped again."

He pointed at the message written on a piece of paper and held up in his direction from one of the television screens.

"At least he remembered not to talk," said Reid. "Why do you suppose they've stopped?"

"How in the world do I know? Maybe they've stopped for a coffee-break. Maybe they've decided to stop for a sunbath. Maybe the girl ..."

He broke off. "Well, I don't know. All I do know is that we have only twenty-four minutes left."

Reid said, "The longer they stay in the inner ear, the more nearly certain it will be that some joker will make a sound-sneeze-something."

"You're right." Carter thought, then said softly, "Oh, for the love of Mike. It's the simple solutions we don't see. Call in that messenger boy."

The security man entered again. He didn't salute.

Carter said. "You still have your shoes off? Okay. Take this down and show it to one of the nurses. You remember about the disemboweling?"

"Yes, sir."

The message read: COTTON AT BENES' EARS.

Carter lit a cigar and watched through the control window as the security man entered, hesitated a moment, then moved with quick, gingerly steps to one of the nurses.

She smiled, looked up at Carter and made a circle of her thumb and forefinger.

Carter said, "I have to think of everything."

Reid said, "It will just deaden the noise. It won't stop it."

"You know what they say about half a loaf," said Carter.

The nurse slipped off her own shoes and was at one of the tables in two steps. Carefully, she opened a fresh box of absorbent cotten and unrolled two feet of it.

She pulled off a fistful in one hand, and seized a fistful in the other. It didn't come readily. She pulled harder, her hand went flying outward, striking a pair of scissors on the table.

It skittered off the table, striking the hard floor. The nurse's foot flew desperately after it, clamping down upon it hard, but not until after it had given out one sharp, metallic clang like the hiccup of a fallen angel.

The nurse's face reddened into a look of deathly horror; everyone else in the room turned to stare; and Carter, dropping his cigar, crumpled into his chair.

"Finished!" he said.

Owens turned on the engine and gently checked the controls. The needle on the temperature gauge, which had been well into the danger zone almost since they had entered the cochlear duct, was dropping.

He said, "It looks good. Are you all set out there?"

Grant's voice sounded in his ear. "Nothing much left. Get ready to move. We're coming in."

And at that moment, the universe seemed to heave. It was as though a fist had driven up against the Proteus, which lifted high. Owens seized a panel for support and held on desperately, listening to a distant thunder.

Below, Duval, as desperately, held on to the laser, trying to cushion it against a world gone mad.

Outside, Grant felt himself flung high in the air as though caught in the grip of a huge tidal wave. He flipped over and over and plunged into the wall of the cochlear duct. He was shaken loose from the wall, which seemed to be caving forward.

Somewhere in a miraculously-calm segment of his mind, Grant knew that on the ordinary scale the wall was responding with rapid vibrations of microscopic amplitude to some sharp sound, but that thought was buried in sheer shock.

Grant tried desperately to locate the Proteus but he caught only a quick glimpse of its headlights flashing against a distant section of the wall.

Cora had been holding on to a projection of the Proteus at the moment the vibration had struck. Instinctively, her grip tightened and for a moment she rode the Proteus as though it were an insanely bucking bronco. The breath was jerked out of her and when her grip was torn away, she went skidding across the floor of the membrane on which the ship had been resting.

The ship's headlights caught the path ahead of her and though she tried in horror to brake her motion it was quite useless. She might as well have tried to dig her heels into the ground in order to stop an avalanche.

She was heading, she knew, for a section of the organ of Corti, the basic center of hearing. Included among the components of the organ were the hair cells; 15,000 of them altogether. She could make out a few of them now; each with its delicate, microscopic cilium held high. Certain numbers of them vibrated gently according to the pitch and intensity of the sound waves conducted into the inner ear and there amplified.

That, however, was as she might have considered it in some course in physiology; phrases as they might have been used in the universe of normal scale. Here what she saw was a sheer precipice and beyond it a series of tall, graceful columns, moving in stately fashion, not all in unison, but rather first one and then another as though a swaying wave were rippling over the entire structure.

Cora went skidding and spinning over the precipice into a world of vibrating columns and walls. Her headlight flashed erratically as she went tumbling downward. She felt the pull of something on her harness and swung forcefully against a firmly-elastic object. She dangled -head downward, afraid to struggle lest whatever projection had stopped her would give way and let her fall the rest of the way.

She spun first this way, then that, as the column against which she clung, a microscopic, cilium on one hair cell of the organ of Corti, continued to sway majestically.

She was managing to breathe now and heard her own name. Someone was calling. Carefully, she made a pleading sound. Encouraged by the sound of her voice, she screamed as shrilly as she could. "Help! Everybody! Help!"

The first devastating shock had passed and Owens was bringing the Proteus under control in a still-turbulent sea. The sound, whatever it was, might have been intense but it had been sharp and quick-dying. That alone saved them. Had it continued for even a short time ...

Duval, cradling the laser under one arm and seated with his back against the wall and his legs pressing desperately against a bench support, shouted, "All clear?"

"I think we pulled through," gasped Owens. "The controls respond."

"We had better leave."

"We've got to pick up the others."

Duval said, "Oh, yes. I had forgotten." Carefully, he rolled over, got one hand beneath to steady himself and then carefully made it to his feet. He still clutched the laser. "Get them in."

Owens called, "Michaels! Grant! Miss Peterson!"

"Coming in," responded Michaels. "I think I'm in one piece."

"Wait," called Grant. "I don't see Cora."

The Proteus was steady now and Grant, breathing heavily, and feeling more than a little shaken, was swimming strongly toward its headlight. He called, "Cora!"

She answered shrilly, "Help! Everybody! Help!"

Grant looked about in every direction. He shouted, desperately, "Coral Where are you?"

Her voice in his ear said, "I can't tell you exactly. I'm caught among the hair cells."

"Where are they? Michaels, where are the hair cells?"

Grant could make out Michaels approaching the ship from another direction, his body a dim shadow in the lymph, his small headlight cutting a thin swath ahead of him.

Michaels said, "Wait, let me get my bearings." He flipped quickly, then shouted, "Owens, turn on ship's headlight wide-angle."

Light spread in response and Michaels said, "This way! Owens, follow me! We'll need the light."

Grant followed Michaels' quickly-moving figure and saw the precipice and columns ahead.

"In there?" he asked uncertainly.

"Must be," returned Michaels.

They were at the edge now, with the ship behind them and its headlight spilling into the cavernous file of columns, still swaying gently.

"I don't see her," said Michaels.

"I do," said Grant, pointing. "Isn't that she? Cora! I see you. Move your arm so I can be certain."

She waved.

"All right. I'm coming to get you."

Cora waited and felt a touch at her knee; the faintest and gentlest sensation, like that of a fly's wing brushing against her. She looked toward her knee but saw nothing.

There was another touch near her shoulder, then still another.

Quite suddenly, she made them out, just a few-the little balls of wool, with their quivering out-thrusting filaments. The protein molecules of the antibodies ...

It was almost as though they were exploring her surface, testing her, tasting her, deciding whether she were harmless or not. There were only a few, but more were drifting toward her from along the columns.

With the headlights from the Proteus shining down, she could make them out clearly, in the glittering reflection of miniaturized light. Each filament shone like a questing sunbeam.

She screamed, "Come quickly. There are antibodies all about." In her thoughts she could see, all too clearly, the antibodies coating the bacterial cell, fuzzing it completely, then crushing it as inter-molecular forces drew the antibodies together.

An antibody had touched her elbow and was clinging there. She shook her arm in revulsion and horror, so that her whole body writhed and went slamming into the column. The antibody did not shake loose. Another joined it, the two fitting together neatly, filaments interlaced.

"Antibodies," muttered Grant.

Michaels said, "She must have done enough damage to surrounding tissue to spark their appearance."

"Can they do anything to her?"

"Not immediately. They're not sensitized to her. No antibodies are deliberately designed for her form. But some will fit somewhere on a sheerly random basis and she will stimulate the formation of more like those that do fit. Then they'll come swarming."

Grant could see them now, swarming already, settling about her like a cloud of tiny fruit-flies.

He said, "Michaels, get back to the sub. One person is enough to risk. I'll get her out of here somehow. If I don't, it will be up to the three of you to get whatever's left of us back into the ship. We can't be allowed to de-miniaturize here-whatever happens."

Michaels hesitated, then said, "Take care," and turned, hastening back to the Proteus.

Grant continued to plunge toward Cora. The turbulence caused by his approach sent the antibodies spinning and dancing rapidly.

"Let's get you out of here, Cora," he panted.

"Oh, Grant. Quickly."

He was pulling desperately at her oxygen cylinders, where they had cut into a column and stuck. Thick strands of viscous material were still oozing outward from the break and it was that, perhaps, which had triggered the arrival of the antibodies.

"Don't move, Cora. Let me . . . Ah!" Cora's ankle was caught between two fibers and he strained them apart. "Now, come with me."

Both executed a half-somersault and started moving away. Cora's body was fuzzed with clinging antibodies but the bulk were left behind. Then, following who knew what kind of equivalent of "scent" on the microscopic scale, they began to follow; first a few, then many, then the entire growing swarm.

"We'll never make it," gasped Cora.

"Yes, we will," said Grant. "Just put every muscle you have into it."

"But they're still attaching themselves. I'm scared, Grant." -

Grant looked over his shoulder at her, then fell back slightly. Her back was half-covered by a mosaic of the wool-balls. They had gauged the nature of her surface well, that part of it at least.

He brushed her back hurriedly, but the antibodies clung, flattening out at the touch of his hand and springing back into shape afterward. A few were now beginning to probe and "taste" Grant's body.

"Faster, Cora!"

"But I can't. .. "

"But you can. Hang on to me, will you?"

They shot upward, over the lip of the precipice, to the waiting Proteus.

Duval helped Michaels up through the hatch. "What's happening out there?"

Michaels pulled off his helmet, gasping. "Miss Peterson was trapped in the Cells of Hensen. Grant is trying to get her loose but antibodies are swarming over her."

Duval's eyes widened. "What can we do?"

"I don't know. Maybe he can get her back. Otherwise, we've got to go on."

Owens said, "But we can't leave them there."

"Of course not," said Duval. "We've got to go out there, all three of us and . . ." Then, harshly, "Why are you back here, Michaels? Why aren't you out there?"

Michaels looked at Duval hostilely, "Because I wouldn't have done any good. I haven't got Grant's muscles or his reflexes. I'd have been in the way. If you want to help, get out there yourself."

Owens said, "We've got to get them back, alive or - or - otherwise. They'll be de-miniaturizing in about a quarter of an hour."

"All right, then," shouted Duval. "Get into your swimsuit and let's get out there."

"Wait," said Owens. "They're coming. I'll get the hatch ready."

Grant's hand was clutching firmly at the wheel of the hatch, while the signal light flashed redly above it. He picked at the antibodies on Cora's -back, pinching the wool-like fibers of one between thumb and forefinger, feeling its soft springiness give and then become a wiry core that gave no further.

He thought: This is a peptide chain.

Dim memories of college courses came back. He had once been able to write the chemical formula of a portion of a peptide chain and here was the real thing. If he had a microscope could he see the individual atoms? No, Michaels had said those would fuzz into nothing no matter what he could do.

He lifted the antibody molecule. It clung tightly at first then gave, sucking free. Neighboring molecules, clinging to it, pulled loose, too. An entire patch came free and Grant swung it away, batting at it. They remained together and came back, seeking a place to cling to again.

They had no brains, not even the most primitive, and it was wrong to think of them as monsters, or predators, or even fruit-flies. They were merely molecules with atoms so arranged as to make them cling to the surfaces that fit theirs through the blind action of inter-atomic forces. A phrase came back to Grant from the recesses of memory - "Van der Waals forces." Nothing more.

He kept pulling at the fuzz on Cora's back. She cried out, "They're coming, Grant. Let's get into the hatch."

Grant looked back. They were finding their way, sensing their presence. Links and chains of them were swooping high above the lip of the precipice and coming down in the general direction like blinded cobras.

Grant said, "We've got to wait . . ." The light turned green. `.'All right. Now." He whirled at the wheel, desperately.

The antibodies were all about them, but making chiefly for Cora. For her they had already been sensitized and there was far less hesitation now. They clung and joined, spanning her shoulders and making their woolly pattern across her abdomen. They hesitated over the uneven three-dimensional curve of her breasts as though they had not figured that out yet.

Grant had no time to aid Cora in her ineffectual clutchings at the antibodies. He pulled the hatch door open, thrust Cora into it, antibodies and all, and followed after her.

He pushed forcefully against the hatch door while antibodies continued to pour in. The door closed upon their elasticity but the basic wiriness of hundreds of them clogged the door at the end. He bent his back against the pressure of that wiriness and managed to turn the wheel that locked the door in place. A dozen little balls of wool, so soft and almost cuddly when viewed separately and in themselves, wriggled feebly in the crack where the hatch door met the wall. But hundreds of others, untrapped, filled the fluid about them. Air pressure was pushing the fluid out and the hissing filled their ears but at the moment, Grant was concerned only to pull the antibodies loose. Some were settling on his own chest, but that didn't matter. Cora's midriff was buried in them, as was her back. They -had formed a solid band about her body from breast to thigh.

She said, "They're tightening, Grant."

Through her mask he could see the agony in her face, and he could hear the effort it took her to speak.

The water was sinking rapidly, but they couldn't wait. Grant hammered at the inner door.

"I - I - can't brea-" gasped Cora.

The door opened, the fluid it "still held pouring into the main body of the ship. Duval's hand thrusting through, seized Cora's arm and pulled her in. Grant followed.

Owens said, "Lord help us, look at them." With an expression of distaste and nausea, he started plucking at the antibodies as Grant had been doing.

A strand tore, then another, then still another. Half-laughing, Grant said, "It's easy, now. Just brush them off."

All were doing so now. They fell into the inch or so of fluid on the floor of the ship and moved feebly.

Duval said, "They're designed to work in body fluid, of course. Once they're surrounded by, air, the molecular attractions alter in nature."

"As long as they're off Cora..."

Cora was breathing in deep, shuddering gasps. Gently, Duval removed her head-piece, but it was to Grant's arm she clung as she suddenly burst into tears.

"I was so scared," she sobbed.

"Both of us were," Grant assured her. "Will you stop thinking it's a disgrace to be frightened. There's a purpose to fear, you know." He was stroking her hair slowly. "It makes the adrenalin flow so that you can swim that much faster and longer and endure that much more. An efficient fear-mechanism is good basic material for heroism."

Duval pushed Grant impatiently to one side, "Are you all right, Miss Peterson?"

Cora took a deep breath and said-with an effort-but in a steady voice, "Quite all right, doctor."

Owens said, "We've got to get out of here." He was in the bubble. "We have practically no time left."