Fantastic Voyage II: Destination Brain fv-2

by Isaac Asimov

  Morrison said, "But since you've never miniaturized anything as large as this ship through so many orders of magnitude, you are depending on the extrapolation of data obtained for a much different size range."

  (They're not speaking to an infant, he thought indignantly. I am their equal.)

  "Yes," said Boranova. "We are taking the chance that the extrapolation will hold, that something new and unexpected will not surprise us. Still, we live in a Universe that faces us with uncertainties now and then. That can't be helped."

  "But we all face death if something goes wrong."

  "Didn't you know that?" said Boranova calmly. "Have you been uneasy about this fantastic voyage of ours simply for the pleasure of being uneasy? But we are not alone in this. If things go wrong and the stored energy of miniaturization is released, it will not only destroy us, but it may damage the Grotto to some extent. I'm sure that many an unminiaturized person out there is holding his or her breath and wondering if he or she will survive an explosion. You see, Albert, even those who are not undergoing the risks of miniaturization are not altogether safe."

  Dezhnev turned and grinned widely. Morrison noted that one of his upper molars was capped and did not match the rather yellowish tint of his other teeth.

  Dezhnev said, "Concentrate on the thought, my friend, that if something goes wrong, you will never know. My father used to say, 'Since we all must die, what better can we ask for than a quick and sudden death?'"

  Morrison said, "Julius Caesar said the same thing."

  Dezhnev said, "Yes, but we won't even have time to say, 'Et tu, Brute.'"

  "There will be no death," said Konev sharply, "and it is foolish to speak of it. The equations are correct."

  "Ah," said Dezhnev. "There was a time of superstition when people relied on the protection of God. Thank Equations we now have Equations to rely on."

  "Not funny," said Konev.

  "I didn't mean to be funny, Yuri. - Natasha, they're ready out there for us to proceed."

  Boranova said, "Then there will be no further need to speculate. Here we go."

  Morrison gripped his seat tightly, preparing himself, but he felt nothing happen. Up front, though, the round circle he had made out expanded and grew dimmer and dimmer as it moved very slowly backward until it could no longer be made out.

  "Are we moving?" he asked automatically. It was the kind of question one was unable to refrain from asking, even though the answer was obvious.

  "Yes," said Kaliinin, "and we are expending no energy in doing so. We are not battling the water molecules. We are being carried along by the water flow in the needle as the cylinder presses in slowly."

  Morrison was counting to himself. It kept his mind more efficiently occupied than studying the second hand of his watch would have done.

  When he reached a hundred, he said, "How long will it take?"

  "How long will what take?" asked Kaliinin.

  "When do we reach the bloodstream?"

  Dezhnev said, "A few minutes. They are going very slowly, just in case there is some kind of microturbulence. As my father once said, 'It is slower, but better, to creep along the downward path than to leap over the cliff.'"

  Morrison grunted, then said, "Are we still miniaturizing?"

  Boranova answered from behind him. "No. We are down in the cellular range and that is far enough for our needs now."

  Morrison was surprised to find that he was trembling. After all, so much was happening and so many new things existed to think about that he had somehow lacked the room to remain in terror. He was not terrified, at least not to an acute stage - yet for some reason he continued to tremble.

  He attempted to will himself to relax. He tried to let himself droop, but that required more than an effort of will. It needed gravitational pull and there was none to speak of. He closed his eyes and slowed his breathing. He even tried humming, under his breath, the choral singing from Beethoven's Ninth Symphony.

  Finally he felt himself forced into comment on the matter. "I'm sorry," he said. "I seem to be shaking."

  Dezhnev snickered. "Aha! I wondered who would be the first to mention it."

  Boranova said, "It's not you, Albert. We are all shaking slightly. It's the ship."

  Morrison was at once elevated into fright. "Is something wrong with it?"

  "No. It's just a matter of size. It's small enough to feel the effect of Brownian motion. You know what that is, don't you?"

  It was a purely rhetorical question. Boranova would surely expect a high school student of physics to know what Brownian motion was, let alone Morrison, and yet Morrison found himself explaining it in his own mind - not in words, but as a flash of concept.

  Every object suspended in a liquid is bombarded on all sides by the atoms or molecules of the liquid. These particles strike randomly and therefore unevenly, but the unevenness is so small compared to the total that it is unnoticeable and has no measurable effect. As an object grows smaller, however, the unevenness becomes greater among the smaller and smaller number of particles striking the object in a given time. The ship was small enough now to respond to the slight excesses of coillisions - first in one direction, then in another - randomly. It moved slightly in consequence, a random trembling.

  Morrison said, "Yes, I should have thought of that. It will get worse if we continue to become smaller."

  "Actually, it won't," said Boranova. "There will be other counteracting effects."

  "I don't know of any," said Morrison, frowning.

  "Nevertheless, there will be such effects."

  "Leave it to the Equations," said Dezhnev in an affectedly pious tone. "The Equations know."

  Morrison said, "I think this could make us seasick."

  "It certainly would," said Boranova, "but there is a chemical treatment for that. We have been dosed with the same chemical that cosmonauts use against space sickness."

  "Not I," said Morrison indignantly. "Not only haven't I been treated, I haven't even been forewarned."

  "We told you as little as possible of the discomforts and dangers out of concern for your comfort, Albert. As for treatment, you consumed your dose with your breakfast. - How do you feel?"

  Morrison, who had begun to feel a bit squeamish with all this talk about sickness, decided that he felt fine. Astonishing, he thought, the tyranny exerted over the body by the mind.

  He said in a low voice, "Tolerable."

  "Good," said Boranova, "because we are now in Academician Shapirov's bloodstream."

  38.

  Morrison stared through the transparent wall of the ship.

  Blood?

  His first impulse was to expect redness. What else?

  He peered out, squinting his eyes slightly, but could see nothing, even in the gleaming light of the ship. He might as well have been in a rowboat, drifting down the calm surface of a pond on a dark and cloudy night.

  Morrison's thoughts suddenly veered. In the absolute sense, the light within the ship had the wavelength of gamma rays - and very hard gamma rays at that. Yet the wavelengths were the result of miniaturizing ordinary visible light and to the equally miniaturized retinas and optic lobes of the people within the ship they were still light rays and had the property of light rays.

  Outside, just beyond the hull of the ship, where the miniaturization field ended, the miniaturized photons enlarged to ordinary light-wave photons and those that were reflected back to the ship were miniaturized again when the field boundary was crossed. The others might be accustomed to this paradox-ridden situation, but to Morrison the attempt to grasp the effect of a miniaturized bubble within a sea of normality was dizzying. Was the boundary visible, marking off the miniaturized from the normal? Was there a discontinuity somewhere?

  Following his line of thought, he whispered to Kaliinin, who was bent over her instrument, "Sophia, when our light leaves the miniaturization field and expands, it must give off heat energy, and when it's reflected back into the ship it must absorb energy in order t
o be miniaturized and the energy must come from us. Am I right?"

  "Perfectly, Albert," said Kaliinin without looking up. "Our use of light results in a small but steady loss of energy, but our motors can supply that. It is not a significant drain."

  "And are we really in the bloodstream?"

  "Never fear. We are. Natalya will probably dim the internal lights in a while and you'll see the outside more clearly then."

  Almost as though that were a signal, Boranova said, "There! Now we can relax for a few moments." The lights dimmed.

  At once, objects outside the ship came dimly into view. He could not make them out clearly yet, but they were immersed in something heterogeneous, something with objects floating in it, as would be true of blood.

  Morrison stirred uneasily, straining at the constraint of his seat belt. He said, "But if we are in the bloodstream, which is at a temperature of thirty-seven degrees Celsius, we'll -"

  "Our temperature is conditioned. We'll be quite comfortable," said Kaliinin. "Really, Albert, we've thought of these things."

  "Perhaps you have," said Morrison, slightly offended, "but I haven't been privy to those thoughts, have I? How can you condition the temperature when you don't have a cold sink?"

  "We don't have one here, but there's outer space, isn't there? The microfusion motors give off a thin drizzle of subatomic particles which, under miniaturized conditions, have a mass of very nearly zero. They therefore travel at virtually the speed of light, penetrating matter as easily as neutrinos do and carrying off energy with them. In less than a second they are in outer space, so that the effect is of transferring heat from within the ship into outer space and we keep cool. Do you see?"

  "I see," muttered Morrison. It was ingenious - but perhaps obvious, after all, to those used to thinking in terms of miniaturization.

  Morrison noticed that the controls of the ship, immediately under Dezhnev's hands, were luminous, as were the instruments before Kaliinin. He struggled to raise himself in his seat and managed to see a corner of the computer screen in front of Konev. It contained what Morrison thought might be a map of the circulatory system of the neck. For a moment, before his body ceased its fight against the webbing of the belt and he sank down into his seat again, he saw a small red dot on the screen, which, he deduced, was a device to mark the position of the ship in the left internal carotid artery.

  He was panting a little from his effort and had to wait a few moments to regain control of his breath. The recess in which his own computer rested was illuminated and he shielded that bit of light from his face by raising his left hand. Then he looked out.

  Far in the distance, Morrison could see something that looked like a wall, a barrier of some sort. It receded, then approached, then receded again, over and over, rhythmically. Automatically, he looked at his watch for a few seconds. It was clearly the pulsation of the arterial wall.

  He said to Kaliinin in a low voice, "Obviously the passage of time is not affected by miniaturization. At least the pulsation of the heart is - just what it ought to be, even though I view it with miniaturized eyes and time it with a miniaturized watch."

  It was Konev who answered. "Time isn't quantized apparently, or at least it isn't affected oy the miniaturization field, which may be the same thing. That's convenient. If we had to take a shifting time flow into account, things might become unbearably complicated."

  Morrison silently agreed and turned his thoughts in other directions.

  If they were inside an artery, and if the ship were merely being swept forward by the current, the forward movement would have to be in spurts, one spurt for each contraction of the distant heart (the very distant heart - on the scale of their present size). And if that were so, he ought to feel those spurts of motion.

  He closed his eyes and tried to hold as still as possible, to move not at all except for the trembling of the Brownian motion - which, after all, he could in no way control.

  Ah, he could feel it. A slight but distinct push backward as the spurt started, a slight push forward as it came to an end.

  But why was the spurt not more energetic? Why was he not yanked backward and forward in a sickening fashion?

  And then he thought of the mass he no longer possessed. With his remaining mass so tiny, his inertia was similarly tiny. The viscosity of the normal fluid of the bloodstream exerted an enormous cushioning effect, so that the spurts were all but lost in the Brownian motion.

  And, ever so slightly, Morrison felt himself relax. He felt something inside himself untighten a bit. The miniaturized environment was unexpectedly benign.

  He looked through the ship's transparent hull again, his eyes focusing on the volume between himself and the arterial wall. He could see bubbles, faintly outlined. No, not bubbles, but things of substance - many of them. Some turned slowly and changed apparent shape as they did so, so they were not spheres. They were disks, he now realized.

  The truth burst in on him and shamed him. Why was he so slow in identifying them, since he knew he was in a bloodstream? - But then he knew the answer to that, too. He could not really conceive of himself as being in a bloodstream; it was too easy to suppose he was in a submarine making its way through an ocean. He would naturally expect to see the familiar sights of an ocean and would be foolishly puzzled at anything he saw that did not fit his assumption.

  He would see the red corpuscles of the blood - the erythrocytes - and fail to recognize them.

  Of course, they weren't red but faintly yellowish. Each one absorbed some shortwave light to produce that color. Get them in bulk, though, millions and billions of them, and they would absorb enough such light to appear red - in arterial blood, anyway, and they were in an artery now. Once the cells withdrew the oxygen carried by the red corpuscles, the individual corpuscle would seem faintly bluish, and, in bulk, blue-purple.

  He watched the erythrocytes with interest and saw them quite clearly now that he had recognized them for what they were.

  They were biconcave discs, the centers depressed on each side. To Morrison, they were enormous, considering that, under normal conditions, they were microscopic, perhaps seven and a half micrometers in diameter and a little over two micrometers thick. Now here they were, swollen objects the size of his hand.

  There were many of them in sight and they had a tendency to pile together in roulettes. These weren't static, however. Some corpuscles would peel off the roulettes and others would add on and there were always some single corpuscles in view. Those that were in sight tended to stay in sight; they weren't moving relative to the ship.

  "I take it," said Morrison, "that we're simply going with the flow."

  "That's right," said Kaliinin. "It saves energy."

  But, at that, the red corpuscles weren't entirely stationary relative to the ship. Morrison noticed one corpuscle drifting slowly toward the ship, carried perhaps by a bit of microturbulence or by a random push of Brownian motion. The corpuscle flattened slightly and momentarily against the plastic of the ship and then rebounded.

  Morrison turned to Kaliinin. "Did you see that, Sophia?"

  "The red corpuscle nudging us? Yes."

  "Why didn't it miniaturize? Surely it entered the field."

  "Not quite, Albert. It bounced off the field, which extends a small distance beyond any miniaturized object, such as our ship, in every direction. There's a certain repulsion between normal matter and miniaturized matter, and the greater the extent of miniaturization, the stronger the repulsion. That's why very tiny objects such as miniaturized atoms or subatomic particles go through matter without interacting with it. It's also that which keeps the miniaturized state metastable."

  "How do you mean?"

  "Any miniaturized object is always surrounded by normal matter, unless it is in deep space. If nothing served to keep normal matter out of the field, such matter would forever be miniaturizing and, in the process, absorbing energy from the miniaturized object. The drain would be significant and the miniaturized object wou
ld quickly deminiaturize. In fact, it would be impossible to induce miniaturization in the first place, since the energy crammed into the miniaturizing object would leak away at once. What we would then be trying to do, in effect, would be to miniaturize the entire Universe. - Of course, the repulsion isn't extremely strong at our size. If a red corpuscle collided with sufficient force, the colliding surface might undergo some miniaturization."

  Morrison turned back to the view and, almost at once, something that was obviously a shredded red corpuscle drifted into view.

  "Ah," said Morrison, "is that an example of one that approached us too forcefully?"

  Kaliinin bent toward Morrison to get a better view in the direction he was pointing. She shook her head. "I don't think so, Albert. Red corpuscles have a limited life of about a hundred and twenty days. The poor things wear out and break down. In the volume of blood we can see, several dozen would break down every minute, so that torn and damaged red corpuscles would be a common sight. - And that is a good thing, too, for it means that if we were to use our power and rush through the bloodstream, breaking up a few red corpuscles, or even a few million, it would make no difference to Shapirov. We couldn't possibly break down red corpuscles at a rate even approaching that of natural breakdown."

  Morrison said, "What about platelets?"

  "Why do you ask?"

  "That must be a platelet I see there." He pointed. "It's lentil-shaped and only half the size of the red corpuscles."

  A pause and then Kaliinin nodded. "Ah yes, I see it now. That's a platelet. There should be one of them to every twenty red corpuscles."

  That was about right, Morrison thought. If he were on a carousel, reaching out for rings as he passed, and reach red corpuscle were an ordinary iron ring, the occasional platelet would represent the coveted brass ring.

  Morrison said, "My point, Sophia, is that platelets are more fragile than red corpuscles and when they break they start the clotting process. If we break a few, we'll start a clot forming in the artery. Shapirov will then have another stroke and surely die."

  Boranova, who had been listening to the exchange between Morrison and Kaliinin, interposed at this point. "In the first place," she said, "platelets are not as fragile as all that. They can strike us lightly and rebound without harm. The danger of another stroke lies at the arterial wall. The platelets are moving much faster relative to the inner wall of the carotid artery than they are relative to us. And the inner wall of the artery may be layered with cholesterol and lipid plaques of all kinds. That surface is therefore much rougher and uneven than the smooth plastic hull of our ship. It's at the arterial wall that the clots might form - not here. And even that isn't too enormous a danger. A single platelet - or even a few hundred of them - might be broken and still be insufficient to start the clotting process in a way that doesn't damp out. Massive quantities of platelets must break to turn the trick."