"That's what I was getting at," Liu said.

"I know; but you see, Liu, Chtexa doesn't know space flight. Oh, ordinary flight stresses are no secret to him — the Lithians fly jets; it was the Haertel overdrive that I was worried about. You'll remember the fantastic time effects that Garrard went through on that first successful Centaurus Sight. I couldn't explain the Haertel equations to Chtexa even if I'd had the time. They're classified against him; besides, he couldn't have understood them, because Lithian math doesn't include transfinites. And time is of the utmost importance in Lithian gestation."

"Why?" Liu said. She peered down into the amphora again, with an instinctive smile.

The question touched a nerve which had lain exposed in Ruiz-Sanchez for a long time. He said carefully: "Because they have physical recapitulation outside the body, Liu. That's why that creature in there is a fish; as an adult, it will be a reptile, though with a pteropsid circulatory system and a number of other unreptilian features. The Lithian females lay their eggs in the sea — "

"But it's fresh water in the jug."

"No, it's sea water; the Lithian seas are not so salt as ours. The egg hatches into a fishlike creature, such as you see in there; then the fish develops lungs and is beached by the tides. I used to hear them barking in Xoredeshch Sfath — they barked all night long, blowing the water out of their lungs and developing their diaphragm musculature."

Unexpectedly, he shuddered. The recollection of the sound was far more disturbing than the sound itself had been. Then, he had not known what it was — or, no, he had known that, but he had not known what it meant.

"Eventually the lungfish develop legs and lose their tails, like a tadpole, and go off into the Lithian forests as true amphibians. After a while, their respiratory system loses its dependence upon the skin as an auxiliary source, so they no longer need to stay near water. Eventually, they become true adults, a very advanced type of reptile, marsupial, bipedal, homeostatic — and highly intelligent. The new adults come out of the jungle and are ready for education in the cities."

Liu took a deep breath. "How marvelous," she whispered.

"It is just that," he said somberly. "Our own children go through nearly the same changes in the womb, but they're protected throughout; the Lithian children have to tun the gauntlet of every ecology their planet possesses. That's why I was afraid of the Haertel overdrive. We insulated the vase against the drive fields as best we could, but in a maturation process so keyed to the appearances of evolution, a time slowdown could have been crucial. In Garrard's case, he was slowed down to an hour a second, then whipped up to a second an hour, then back again, and so on along a sine wave. If there'd been the slightest break in the insulation, something like that might have happened to Chtexa's child, with unknowable results. Evidently, there was no leak, but I was worried."

The girl thought about it. In order to keep himself from thinking about it, for he had already pondered himself in dwindling spirals to a complete, central impasse, Ruiz-Sanchez watched her think. She was always restful to watch, and Ruiz-Sanchez needed rest. It now seemed to him that he had had no rest at all since the moment when he had fainted on the threshold of the house in Xoredeshch Sfath, directly into the astonished Agronski's arms.

Liu had been born and raised in the state of Greater New York. It was Ruiz-Sanchez' most heartfelt compliment that nobody would have guessed it; as a Peruvian he hated the nineteen-million-man megalopolis with an intensity he would have been the first to characterize as unchristian. There was nothing in the least hectic or harried about Liu. She was calm, slow, serene, gentle, her reserve unshakable without being in the least cold or compulsive, her responses to everything that impinged upon her as direct and uncomplicated as a kitten's; her attitude toward her fellow men virtually unsuspicious, not out of naivete, but out of her confidence that the essential Liu was so inviolable as to prevent anyone even from wanting to violate it. These were the abstract terms which first came to Ruiz-Sanchez' mind, but immediately he came to grief over a transitional thought. As nobody would take Liu for a New Yorker — even her speech betrayed not a one of the eight dialects, all becoming more and more mutually unintelligible, which were spoken in the city, and in particular one would never have guessed that her parents spoke nothing but Bronix — so nobody could have taken her for a female laboratory technician.

This was not a line of thought that Ruiz-Sanchez felt comfortable in following, but it was too obvious to ignore. Liu was as small-boned and intensely nubile as a geisha. She dressed with exquisite modesty, but it was not the modesty of concealment, but of quietness, of the desire to put around a firmly feminine body clothes that would be ashamed of nothing, but would also advertise nothing. Inside her soft colors, she was a Venus Callipygous with a slow, sleepy smile, inexplicably unaware that she — let alone anybody else — was expected by nature and legend to worship continually the firm dimpled slopes of her own back. There now, that was quite enough; more than enough. The little eel chasing fresh-water crustaceae in the ceramic womb presented problems enough, some of which were about to become Liu's. It would hardly be suitable to complicate Liu's task by so much as an unworthy speculation, though it be communicated by no more than a curious glance. Ruiz-Sanchez was confident enough of his own ability to keep himself in the path ordained for him, but it would not do to burden this grave sweet girl with a suspicion her training had never equipped her to meet.

He turned away hastily and walked to the vast glass west wall of the laboratory, which looked out over the city thirty-four storeys from the street — not a great height, but more than sufficient for Ruiz-Sanchez. The thundering, heat-hazed, nineteen-million-man megalopolis repelled him, as usual — or perhaps even more than usual, after his long stay in the quiet streets of Xoredeshch Sfath. But at least he had the consolation of knowing that he did not have to live here the rest of his life. In a way, the state of Manhattan was only a relic anyhow, not only politically, but physically. What could be seen of it from here was an enormous multi-headed ghost. The crumbling pinnacles were ninety per cent empty, and remained so right around the clock. At any given moment most of the population of the state (and of any other of the thousand-odd city-states around the globe) was underground. The underground area was self-sufficient. It had its own thermonuclear power sources; its own tank farms, and its thousands of miles — of illuminated plastic pipe througn which algae suspensions flowed richly, grew unceasingly; decades worth of food and medical supplies in cold storage; water-processing equipment which was a completely closed circuit, so that it could recover moisture even from the air and from the city's own sewage; and air intakes equipped to remove gas, virus, fall-out particles or all three at once. The city-states were equally independent of any central government; each was under the hegemony of a Target Area Authority modeled on the old, self-policing port authorities of the previous century — out of which, indeed, they had evolved inevitably.

This fragmentation of the Earth had come about as the end product of the international shelter race of 1960-85. The fission-bomb race, which had begun in 1945, was effectively over five years later; the fusion-bomb race and the race for the intercontinental ballistic missile had each taken five years more. The Shelter race had taken longer, not because any new physical knowledge or techniques had been needed to bring it to fruition — quite the contrary — but because of the vastness of the building program it involved.