Miss Fellowes said, "Couldn't you get him back? The way you got the rock in the first place?"

"No, because once an object is returned, the origirtal fix will be lost unless we take steps ahead of rime to retain it-and we wouldn't have done that in this case. As a matter of fact, we never take such steps in any case. There's no reason for it. Finding the professor again would mean relocating a specific fix across five million years or thereabouts and that would be like dropping a line into the oceanic abyss for the purpose of dredging up one particular fish. -My God, when I think of the precautions we take to prevent accidents, it makes me furious. We have every individual Stasis unit set up with its own puncturing device-we have to, since each unit has its own separate fix and needs to be independently collapsible. The point is, though, none of the puncturing devices is ever activated until the last minute. And then we deliberately make activation impossible except by- you saw me do it, didn't you?-by the pull of a lever whose handle is carefully placed outside Stasis. The pull is gross mechanical motion that requires a strong effort, not something that's likely to be done accidentally."

"So you'd simply have to leave Professor Adamewski back there in-what did you say?-the Pliocene?"

"There'd be no alternative."

"And the Pliocene was five million years ago?"

"It began about ten million years ago, as a matter of fact. And lasted for something like eight million years. But that particular rock came from five million years back."

"Would the professor have been able to survive there very long, do you think?"

Hoskins turned his hands upward in a gesture of uncertainty. "Well, the climate probably wouldn't be as rough as it would get later on in the glacial period your Timmie comes from, and the atmosphere he'd find himself in would be more or less identical to the stuff we breathe today-minus a lot of the garbage that we've pumped into it in the past couple of hundred years, of course. So if Adamewski knew anything about hunting and finding edible plants, which I would say is highly doubtful, he'd have been able to cope for a while. Anywhere between two weeks and two months, is my guess." "Well, what if he met some Pliocene woman during that rime, and she took a liking to him and taught him how to gather food?" Then an even wilder idea occurred to Miss Fellowes. -"And he might even mate with her back there and they would have children, a whole new genetic line, a modern man's genes combining with those of a prehistoric woman. Wouldn't that change all of history to come? That would be the biggest risk of having the professor go back in time, wouldn't it?"

Hoskins was trying to smother an attack of giggles. Miss Fellowes felt her face turning a hot red. "Have I said something very stupid, doctor?"

It was another moment before he was able to reply. "Stupid? Well, that's too harsh a word. -Naive, is what I'd prefer to say. Miss Fellowes, there weren't any women conveniently waiting back there in the Pliocene for our Dr. Adamewski to set up housekeeping with. Not anybody that he'd regard as an eligible mate, anyway." "I see."

"I forget most of the details of what I once knew about hominid ancestry, but I can tell you quite confidently that Adamewski wouldn't have found anything that looked like Homo sapiens back there. The best he could hope for would be some primitive form of australo-pithecine, maybe four feet tall and covered with hair from head to toe. The human race as we understand it simply hadn't evolved at such an early date. And I doubt that even a passionate man like Dr. Adamewski"-Hoskins smothered another burst of giggles-"would find himself so enamored of your average Pliocene hominid ferrtale that he'd want to have sexual relations with her. Of course, if he ran into the Pliocene equivalent of Helen of Troy-the ape that launched a thousand ships, so to speak-"

"I think I get the point," Miss Fellowes said primly, regretting now that she had led the discussion in this direction in the first place. "But I asked you before, when you showed me the dinosaur, why it was that moving something in and out of time doesn't change history. I understand now that the professor wouldn't have been able to start a family in the Pliocene, but if you sent someone back in time to an era when there were actual human beings-say, twenty thousand years ago-"

Hoskins looked thoughtful. "Well, then, there'd be some minor disruption of the time-line, I suppose. But I don't think there'd be anything big."

"So you simply can't change history using Stasis?"

"Theoretically, yes, you can, I suppose. Actually, except in really unusual cases, no. We move objects out of Stasis all the time. Air molecules. Bacteria. Dust. About ten per cent of our energy consumption goes to make up micro-losses of that sort. But even moving large objects in time sets up changes that damp out. Consider Adamew-ski's chunk of chalcopyrite from the Pliocene. During the two weeks it was up here in our time, let's say, some insect that might have taken shelter under it couldn't find it, and was killed. That could initiate a whole series of changes along the time-line, I imagine. But the mathematics of Stasis indicates that it would be a converging series. The amount of change tends to diminish with time and eventually things return to the track they would have followed all along."

"You mean, reality heals itself?"

"In a manner of speaking. Yank a human being out of the past, or send one back, and you make a larger wound. If the individual is an ordinary one, that wound would still heal itself-that's what the calculations show. Naturally there are a great many people who write to us every day and want us to bring Abraham Lincoln into the present, or Mohammed, or Alexander the Great. Well, we don't have the technical ability to do that just yet, not that we'd be likely to if we could. But even if we could cast our net such a short distance into the past, and were able to locate a specific human being such as the three 1 named, the change in reality involved in moving one of the great molders of history would be too huge to be healed. There are ways of calculating when a change is likely to be too great, and we make sure that we don't come anywhere near that limit."

Miss Fellowes said, "Then Timmie-" "No, he doesn't present any problems of that sort. One small boy who belonged to a human subspecies that was destined to die out in another five or ten thousand years is hardly going to be a history-changer because we've brought him forward to our era. Reality is safe." Hoskins gave her a quick, sharp glance. "You don't need to worry about it."

"I'm not. I'm just trying to understand how things work around here." "Which I applaud."

Miss Fellowes took a long deep sip of her buttermilk. "If there wasn't any historical risk in bringing one Neanderthal child into our time, then it would be possible to bring another one eventually, wouldn't it?"

"Of course. But one is all we'll need, I imagine. If Timmie helps us learn everything that we want to-"

"I don't mean to bring another one here for purposes of research. I mean as a playmate for Timmie." "What?"

It was a concept diat had burst into her mind as suddenly and unexpectedly as the name "Timmie" itself had-an impulse, a spontaneous thing. Miss Fellowes was astonished at herself for having brought it up.

But she pursued it, now that it was here.

"He's a normal, healthy child in every way, so far as I can see. A child of his time, of course. But in his own way I think he's outstanding."

"I certainly think so too, Miss Fellowes."

"His development from here on, though, may not continue normally."

"Why not?" Hoskins asked.

"Any child needs stimulation and this one lives a life of solitary confinement. I intend to do what I can, but I can't replace an entire cultural matrix. What I'm saying, Dr. Hoskins, is that he needs another boy to play with."

Hoskins nodded slowly. "Unfortunately, there's only one of him, isn't there? Poor child."

Miss Fellowes watched him shrewdly, hoping that she had picked the right moment for this.

"If you could bring a second Neanderthal forward to share his quarters with him-"

"Yes. That would be ideal, Miss Fellowes. -But of course it can't be done."

"It can't?" said Miss Fellowes, with sudden dismay.

"Not with the best will in the world, which I like to think is what we have. We couldn't possibly expect to find another Neanderthal close to his age without incredible luck-it was a very sparsely populated era, Miss Fellowes; we can't just dip casually into the Neanderthal equivalent of a big city and snatch a child-and even if we could, it wouldn't be fair to multiply risks by having another human being in Stasis."

Miss Fellowes put down her spoon. Heady new ideas were flooding into her mind. She said energetically, "In that case, Dr. Hoskins, let me take a different tack. If it's impossible to bring another Neanderthal child into the present, so be it. I'm not even sure I could cope with a second one, anyway. But what if- a little later, once Timmie is better adapted to modern life - what if we were to bring another child in from the outside to play with him?"

Hoskins stared at her in concern. "A human child?"

"Another child," said Miss Fellowes, with an angry glare. "Timmie is human."

"Of course. You know what I meant. - But I couldn't dream of such a thing."

"Why not? Why couldn't you? I don't see anything wrong with the idea. You pulled that child out of time and made him an eternal prisoner. Don't you owe hint something? Dr. Hoskins, if there is any man who, in this present-day world, can be considered that child's father - in every sense but the biological - it's you. Why can't you do this litde thing for him?"

Hoskins said, "His father?" He rose, somewhat unsteadily, to his feet. "Miss Fellowes, I think I'll take you back now, if you don't mind."

They returned to the dollhouse that was Stasis Section One in a bleak silence that neither broke.

As he had promised, Mclntyre sent over a stack of reference works that dealt with Neanderthals. Miss Fellowes plunged into them as if she were back at nursing school and a critical exam was coming up in a couple of days.