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 would 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."

Morrison watched a platelet that vanished, now and then, behind the numerous red corpuscles. He wanted to see if it would make contact with the ship and, if it did, what would happen. The platelet, however, did not oblige but remained at a distance.

It then occurred to Morrison that the platelet appeared to be as large as his hand. How could that be if they were half the diameter of the red corpuscles and the red corpuscles were themselves as large as his hand? His eyes sought out a red call and, sure enough, it seemed considerably larger than his hand.

He said, troubled, "The objects out there are getting larger."

"We're still miniaturizing, obviously," called out Konev, apparently annoyed at Morrison's seeming inability to draw the proper conclusion from an observed fact.

Boranova said, "That's right, Albert. The coronary is narrowing as we progress and we want to keep pace with it."

"We don't want to get stuck in the pipe," said Dezhnev genially, "by being too fat." Then, as another thought struck him, he added, "You know, Natasha, I've never been this thin in my life."

Boranova said, unmoved, "You are as fat as ever, Arkady, on the scale of Planck's constant."

Morrison was in no mood for airy banter. "But how far do we miniaturize, Natalya?"

"Down to molecular size, Albert."

And all of Morrison's apprehensions surged up again.

Morrison felt foolish at his failure to realize at once that they were still miniaturizing and, at the same time, bitterly resentful at Konev for making it plain he recognized that folly. The trouble was that all these others had been living and thinking miniaturization for years and he himself, a newcomer to the concept, was still trying to cram it into his reluctant brain. Couldn't they sympathize with his difficulties?

He studied the red corpuscles moodily. They were distinctly larger. They were wider across than his chest and their boundaries were becoming less sharp. Their surfaces quivered, as though they were canvas bags full of syrup.

He said in a low voice to Kaliinin, "Molecular size?"

Kaliinin looked quickly at him, then turned away and said, "Yes."

Morrison said, "I don't know why that should bother me, considering the small size to which we have already miniaturized, but there's something rather frightening about being as small as a molecule. How small a molecule, do you suppose?"

Kaliinin shrugged. "I don't know. That's up to Natalya. A virus molecule, perhaps."

"But this sort of thing has never been tried."

Kaliinin shook her head. "We're charting unknown territory."

There was a pause and then Morrison said uneasily, "Aren't you afraid?"

She looked at him furiously, but continued to whisper. "Of course I'm afraid. What do you think I am? It isn't sensible not to be afraid when you have rational reason for it. I was afraid when I was violated. I was afraid when I was pregnant and deserted. I've spent half my life being afraid. Everyone does. That's why people drink as much as they do, to wipe out the fear that grips them." She was virtually hissing through clenched teeth. "Do you want me to be sorry for you because you're afraid?"