In the control room, the television receivers seemed to spring back into life.

"General Carter ... "

"Yes, what now?"

"They're moving again, sir. They're out of the ear and heading rapidly for the clot."

"Hah!" He looked at the Time Recorder, which read 12. "Twelve minutes." Vaguely, he looked about for the cigar and found it on the floor where he had dropped it and then stepped on it. He picked it up, looked at its flatly mangled shape and threw it away in disgust.

"Twelve minutes. Can they still make it, Reid?"

Reid was crumpled in his chair, looking miserable. "They can make it. They can even get rid of the clot, maybe.

"But..."

"But?"

"But I don't know if we can get them out in time. We can't probe into the brain to pull them out, you know. If we could do that, we would have been able to probe into it for the clot in the first place. That means they've got to get to the brain and then proceed to some point where they can be removed. If they don't ... "

Carter said, querulously. "I've been brought two cups of coffee and one cigar and I haven't had one sip or one puff ..."

"They're reaching the base of the brain, sir," came the word.

Michaels was back at his chart. Grant was at his shoulder, staring at the complexities before him.

"Is that the clot here?"

"Yes," said Michaels.

"It looks a long distance off. We only have twelve minutes."

"It's not as far away as it looks. We'll have clear sailing now. We'll be at the base of the brain in less than a minute and from there, in no time at all ... "

"There was a sudden flood of light pouring in all about the ship. Grant looked up in astonishment and saw, outside, a tremendous wall of milky light, its boundaries invisible.

"The ear-drum," said Michaels. "On the other side, the outside world."

An almost unbearably poignant homesickness pulled at Grant. He had almost forgotten that there was an outside world. It seemed to him at that moment that all his life he had been travelling endlessly through a nightmare world of tubes and monsters, a Flying Dutchman of the circulatory system ...

But there it was, the light of the outside world, filtering through the ear-drum.

Michaels said, bending over the chart, "You ordered me back into the ship from the hair cells, didn't you, Grant?"

"Yes, I did, Michaels. I wanted you on the ship, not at the hair cells."

"You tell that to Duval. His attitude ... "

"Why worry. His attitude is always unpleasant, isn't it?"

"This time, he was insulting. I don't pretend to be a hero . . ."

"I'll bear witness on your behalf."

"Thank you, Grant. And-and keep an eye on Duval."

Grant laughed. "Of course."

Duval approached, almost as though he realized he was being discussed and said, brusquely, "Where are we, Michaels?"

Michaels looked at him with a bitter expression and said, "We're about to enter the sub-arachnid cavity. -Right at the base of the brain," he added, in Grant's direction.

"Okay. Suppose we go in past the oculomotor nerve."

"All right," said Michaels. "If that will give you the most favorable shot at the clot, that's how we'll go in."

Grant backed away, and bent his head to get into the storage room where Cora was lying on a cot.

She made as though to get up, but he lifted his hand. "Don't. Stay there." And he sat on the floor beside her, knees up and enclosed in his arms. He smiled at her.

She said, "I'm all right now. I'm just malingering, lying here."

"Why not? You're the most beautiful malingerer I've ever seen. Let's malinger together for a minute, if you don't think that sounds too improper."

She smiled in her turn. "It would be difficult for me to complain that you were too forward. After all, you seem to make a career of saving my life."

"All part of a shrewd and extraordinarily subtle campaign to place you under an obligation to me."

"I am! Most decidedly!"

"I'll remind you of that at the proper time."

"Please do. -But Grant, really, thank you."

"I like your thanking me, but it's my job. That's why I was sent along. Remember. I make decisions on policy and I take care of emergencies."

"But that's not all, is it?"

"It's quite enough," protested Grant. "I plug snorkels into lungs, pull seaweed out of intakes and most of all I hold on to beautiful women."

"But that's not all, is it? You're here to keep an eye on Dr. Duval, aren't you?"

"Why do you say that?"

"Because it's true. The higher echelons at the CMDF don't trust Dr. Duval. They never have."

"Why is that?"

"Because he is a dedicated man; completely innocent and completely involved. He offends others not because he wants to, but because he honestly doesn't know he's offensive. He doesn't know that anything exists beside his work..."

"Not even beautiful assistants?"

Cora flushed. "I suppose-not even assistants. But he values my work; he really does."

"He'd keep right on valuing your work, wouldn't he, if someone else valued you?"

Cora looked away, then went on firmly, "But he's not disloyal. One trouble is he favors free exchange of information with the Other Side and says so because he doesn't know how to keep his views unobtrusive. Then, when others disagree with him he tells them how foolish he thinks they are."

Grant nodded. "Yes, I can imagine. And that makes everybody love him because people just adore being told how foolish they are."

"Well, that's the way he is."

"Look. Don't sit there and worry. I don't mistrust Duval, any more than I do anyone else."

"Michaels does."

"I know that. Michaels has moments where he mistrusts everyone, both in this ship and outside. He even mistrusts me. But I assure-you I give that only the weight I think it deserves."

Cora looked anxious. "You mean Michaels thinks I deliberately damaged the laser? That Dr. Duval and I together . . ."

"I think he thinks of that as a possibility."

"And you, Grant?"

"I think of it as a possibility, too."

"But do you believe it?"

"It is a possibility, Cora. Among many possibilities. Some possibilities are better than others. Let me worry about that end of it."

Before she could answer, both heard Duval's voice raised anger: "No, no, no. It's out of the question, Michaels. won't have a jackass tell me what to do."

"Jackass! Shall I tell you what you are, you ..."

Grant was out front, Cora directly behind him. Grant said, "Hold it, both of you. What's up?"

Duval turned and said, fuming. "I have the laser back in order. The wire is shaved to the proper size; its joined to the transistor; and it's back in place. I've just told that to this jackass here . . ." He turned his face toward Michaels and snapped out, "Jackass, I said," then went on, "because he asked me about it."

"Well, good," said Grant. "What's wrong with that?"

Michaels said, heatedly, "Because the mere fact of his saying so doesn't make it so. He's put some things together. I can do that much. Anyone can. How does he know it will work?"

"Because I know. I've worked with lasers for twelve ears. I know when they work."

"Well, then, show us, doctor. Let us share your knowledge. Use it."

"No! Either it works or it doesn't work. If it doesn't work, I can't fix it under any circumstances because I've done all I can and nothing further can be done. That means we'll be worse off if I wait till we get to the clot to find out that 'it doesn't work. But if it works, and it will work, it remains jerry-rigged. I don't know how long it will last; a dozen blasts or so at most. I want to save every one of those blasts or the clot. I won't waste a single one of them here. I won't have the mission fail because I tested the laser even once."

"I tell you, you've got to test the laser," said Michaels. "If you don't, then I swear, Duval, that when we get back, I will have you thrown out of the CMDF so far and have you broken into so many small pieces ..."

"I'll worry about that when we get back. Meanwhile this is my laser and I do as I please with it. You can't order me to do anything I don't wish to do, and neither can Grant."

Grant shook his head. "I'm not ordering you to do anything, Dr. Duval."

Duval nodded briefly and turned away.

Michaels looked after him. "I'll get him."

"He makes sense in this case, Michaels," said Grant. "Are you sure you're not annoyed with him for personal reasons?"

"Because he calls me coward and jackass? Am I supposed to love him for that? But whether I have personal animosity against him or not doesn't matter. I think he's a traitor."

Cora said, angrily, "That's quite untrue."

"I doubt," said Michaels freezingly, "that you're a reliable witness in this case. -But never mind. We're getting to the clot and we'll see about Duval then."

"He'll clear that clot," said Cora, "if the laser works."

"If it works," said Michaels. "And if it does, I wouldn't be surprised if he kills Benes. And not by accident."

Carter had his jacket off and his sleeves rolled up. He was slumped in his chair on the base of his spine and a second cigar, freshly-lit, was in his mouth. He wasn't puffing.

"In the brain?" he said.

Reid's mustache seemed bedraggled at last. He rubbed his eyes. "Practically at the clot. They've stopped."

Carter looked at the Time Recorder, which read 9.

He felt used up, out of juice, out of adrenalin, out of tension, out of life. He said, "Think they'll make it?"

Reid shook his head. "No, I don't."

In nine minutes, maybe ten, the men, ship and all, would be standing full-size before them-exploding Benes' body, if they hadn't gotten out in time.

Carter thought of what the newspapers would make of CMDF if this project failed. He heard the speeches from every politician in the land, and from those on the Other Side. How far would CMDF be set back? How many months-years-would it take it to recover?

Wearily, he began to write his letter of resignation in his mind.

"We've entered the brain itself," announced Owens, with controlled excitement.

He doused ship's lights again and all of them looked forward in a moment of wonder that put everything else, even the climax of the mission, out of their minds for a moment.

Duval murmured, "How wonderful. The supreme peak of Creation."

Grant, for the moment, felt that. Surely the human brain was the most intensely complicated object crowded into the smallest possible volume in all the universe.

There was a silence about their surroundings. The cells they could see were jagged, uneven, with fibrous dendrites jutting out here and there, like a bramble-bush.

As they drifted through the interstitial fluid along passageways between the cells, they could see the dendrites tangling overhead and for a moment they were passing under what seemed the twisted limbs of a row of ancient forest tress.

Duval said, "See, they don't touch. You can see the synapses clearly; always that gap which must be jumped across chemically."

Cora said, "They seem to be full of lights."

Michaels said, an edge of anger still in his voice, "A mere illusion. The reflection of miniaturized light plays tricks. It bears no relation to reality."

"How do you know?" demanded Duval, at once. "This is an important field for study. The reflection of miniaturized light is bound to vary subtly with the structure of the molecular contents of the cell. This sort of reflection, I predict, will become a more powerful instrument for studying the micro-details of the cell than any now existing. It may well be that the techniques arising out of this mission of ours will be far more important than what happens to Benes."

"Is that how you're excusing yourself, doctor?" asked Michaels.

Duval reddened. "Explain that!"

"Not now!" said Grant, imperiously. "Not one more word, gentlemen."

Duval drew a deep breath and turned back to the window.

Cora said, "But anyway, do you see the lights? Watch up above. Watch that dendrite as it comes close."

"I see it," said Grant. The usual glittering reflections did not, as had been generally true elsewhere in the body, sparkle from this point and that randomly, making the whole look like a dense cloud of fire-flies. Instead, the sparkle chased itself along the dendrite, a new one beginning before the old one had completed its path.

Owens said, "You know what it looks like. Anyone ever see films of old-fashioned advertising signs with electric lights? With waves of light and dark moving along?"

"Yes," said Cora. "That's exactly what it's like. But why?"

Duval said, "A wave of depolarization sweeps along a nerve fiber when it is stimulated. The ion concentrations change; sodium ion enters the cell. This changes the charge intensity inside and out and lowers the electric potential. Somehow that must affect the reflection of miniaturized light-which is exactly the point I was making-and what we see is the wave of depolarization."

Now that Cora had pointed out the fact-or perhaps because they were moving ever deeper into the brain, the moving wave of sparkles could be seen everywhere; moving along the cells, climbing and descending fibers, twisting into an unimaginably complex system which seemed, at first glance, without any form of order, and yet which gave the sense of order, anyway.

"What we see," said Duval, "is the essence of humanity. The cells are the physical brain, but those moving sparkles represent thought, the human mind."

"Is that the essence," said Michaels, harshly. "I would have thought it was the soul. Where is the human soul, Duval?"

"Because I can't point it out, do you think it doesn't exist?" demanded Duval. "Where is Benes', genius? You are in his brain. Point to his genius."

"Enough!" said Grant.

Michaels called up to Owens. "We're almost there. Cross over into the capillary at the indicated point. Just push through."

Duval said thoughtfully, "That's the awesome thing of it. We're not just in the mind of a man. This, all about us, is the mind of a scientific genius; someone I would put almost on a par with Newton."

He was silent for a moment and then quoted:

"... Where the statue stood Of Newton with his prism and silent face. The marble index of a mind . . ."

Grant cut in, with an awed whisper:

"... forever Voyaging through strange seas of thought, alone."

Both were silent for an instant, and Grant said, "Do you think Wordsworth ever thought of this, or could have, when he spoke of `strange seas of thought.' This is the literal sea of thought, isn't it? And strange it is, too."

Cora said, "I didn't think of you as the poetic type, Grant."

Grant nodded. "All muscle, no mind. That's me."

"Don't be offended."

Michaels said, "When you are done with mumbling poetry, gentlemen, look ahead."

He pointed. They were in the blood-stream again, but the red corpuscles (bluish in color) drifted without any definite motion, shuddering slightly in response to Brownian motion, no more. Up ahead was a shadow.

A forest of dendrites could be seen through the transparent walls of the capillary; each strand, each twig with its line of sparkle moving along itself-but more slowly now, and still more slowly. And after a certain point, there were no more sparkles.

The Proteus came to a halt. For an instant or two, there was silence, then Owens, said quietly, "That's our destination, I think."

Duval nodded. "Yes. The clot."