Very well, then. He had passed from desperately not wanting to attempt the project to a definite reluctance to abort it.

Dezhnev's voice broke in on his thoughts. "I don't think this little animal likes what's happening."

Morrison was conscious of a biting chill, and shivered as he became aware that the thin cotton uniform he wore was a totally inadequate shield against this sudden onset of winter.

And perhaps the white cell "thought" this, too, for the fog thinned and a rift appeared in it. Then, in another moment or two, the surroundings were clear and the white cell was a ball of fog to their rear, drifting away - or perhaps crawling away - amoebalike, from an unpleasant experience.

Boranova said (sounding a little dumbfounded), "Well, it's gone."

Dezhnev waved both hands high in the air. "A toast - if we had a small swallow of vodka with us - to our American hero. It was an excellent suggestion."

Kaliinin nodded at Morrison and smiled. "It was a good idea."

"As good as mine was bad," said Boranova, "but at least we know that your technique can do what it should, Sophia - as long as we know enough. And as for you, Arkady, ease the air-conditioning intensity before we all catch pneumonia. - So you see, Albert, we have already done well to take you with us."

"Perhaps," said Konev tightly, "but in the meanwhile, I think the white cell took us on an excursion. We are not where we were and I do not know exactly where we are."

Boranova's lips tightened and she asked with some difficulty, "How can you not know where we are? We were inside the white cell only a few minutes. It couldn't have moved us into the liver, could it?"

Konev seemed at least equally upset. "No, we're not in the liver, Madame." (He came down heavily on the honorific, giving it the French pronunciation.) "But I suspect the white cell, dragging us with it, has turned into a branching capillary so that we are now out of the mainstream of the arteriole - which was not yet quite a capillary - that we were carefully following."

"Which capillary did it turn into?" asked Boranova.

"That is what I don't know. There are a dozen capillaries it might have turned into and I don't know which one it was."

"Doesn't your red marker -" began Morrison.

"My red marker," said Konev at once, "works by dead reckoning. If I know where we are and the speed at which we're progressing, it will move along with us, turning when I tell it to turn."

"You mean," said Morrison incredulously, "it only marks your position insofar as you know your position - no more than that?"

"It is not a magical marker, no," said Konev freezingly. "It acts to mark our place and keep track of it, lest we lose it in the confusion of the three-dimensional complexity of the bloodstream and the neuronic networks, but we have to guide it. At this stage, it's not complex enough to guide itself. In an emergency, we can be located from outside, but that's a time-consuming process."

It seemed to be time for someone to ask a classically foolish question and that someone turned out to be Dezhnev. He said, "Why should the white cell have turned off into a capillary?"

Konev turned red. Speaking so rapidly that Morrison could hardly make out the Russian, he said, "And how should I know that? Am I privy to the thought processes of a white cell?"

"That's enough," said Morrison sharply. "We're not here to fight with each other." (He noted the quick look that Boranova had shot toward him and he chose to interpret it as representing gratitude.)

"Actually," he went on, "the solution is simple. We're in a capillary. Very well. The current is at a creeping pace in capillaries, so where is the difficulty in making use of the famous microfusion engines? If you put them into reverse, we will just back out of this capillary and eventually - not a very long eventually, either - we will be back at the junction point and in the arteriole again. Then we continue onward until we get to the proper turnoff and into the proper capillary. We'll have lost a little time and spent a little power, that's all."

Morrison's statement was greeted with solemn stares. Even Konev, who generally spoke - when he did - with his face steadfastly forward, turned now, his angry frown concentrated on Morrison.

Morrison said uneasily, "Why are you all looking at me like that? It's a perfectly natural course of procedure. If you had been driving a car and accidentally turned into a narrow alley and found it the wrong one, wouldn't you back out?"

Boranova was shaking her head. "Albert, I'm sorry. We have no reverse."

"What?" Morrison stared at her blankly.

"We have no reverse. We have only a forward drive. Nothing more."

Morrison said, "How is it possible to - No reverse gear at all?"

"None."

Morrison looked around at the other four faces and then burst out, "Of all the stupid, incompetent, maddening situations. It's only in the Sov-"

He stopped.

Boranova said, "Finish the thought. You were going to say that it's only in the Soviet Union that such a situation would be allowed to arise."

Morrison swallowed, then said grumpily, "I was going to say that, yes. It might be an ill-tempered statement, but I'm angry - and the statement may be true, at that."

"And do you think we're not angry, Albert?" said Boranova with her glance level upon him. "Do you know how long we've been working on a ship like this? Years! Many years! Since miniaturization first seemed to become a practical possibility, we have been thinking of entering a bloodstream someday and exploring the working mammalian body - if not the human body - from within.

"But the more we planned and the more we designed, the more expensive the project grew, and the more stubborn the budgeteers in Moscow became in response. I can't blame them; they had to balance the expense of this project against other expenses in areas that were far less problematical than miniaturization was. So, as a result, the ship grew simpler and simpler in concept, as we cut out first this, then that, then the other thing. Do you remember when you Americans were building your first shuttles? What you planned and what you got?

"In any case, we ended up with an unpowered craft, fit for observation only. We planned to enter the bloodstream and let the current carry us where it would. When we had all the information we could get, we would slowly deminiaturize. This would kill the animal which we had been studying - it would only be an animal, of course, but even so some of us agonized over that. That was all this ship was planned for. Nothing more. We had no way of knowing that we would suddenly be faced with a situation in which we had to invade a human body, in which we had to get to a specific spot in the brain, in which we would have to emerge without killing the body. In which we had to - and all we had was this ship, which was not meant for the job at all."

The anger and contempt on Morrison's face had vanished into a frown of concern. "What did you do?"

"We worked as fast as we could. We improved the microfusion motors and a few other things, frightened that at any moment Shapirov would die, and equally frightened - or more so - that our hurry would cause us to make some fatal mistake. Well, I don't think we made any fatal mistakes, but still the microfusion motors we ended up with were to be used for acceleration only when absolutely necessary - they had originally been designed only for lighting, air-conditioning, and other low-energy uses. Of course, we lacked the time to do a complete job, so - no reverse gear."

"Didn't anyone point out that there might just be a chance you would want to go into reverse?"

"That would mean more money and there was none to be had. After all, we had to compete with space, which was a going concern, with the realistic needs of agriculture, commerce, industry, crime control, and half a hundred other departments of government all clutching at the national purse. Of course we never had enough."