Within was a sulidor not yet asleep, standing over three of the sluggish serpents of the tropics, which moved in gentle coils about him. The sulidor was huge, age-grizzled, a being of unusual presence and dignity.

“Na-sinisul?” Gundersen asked.

“We knew that in time you must come here, Edmundgundersen.”

“I never imagined — I didn’t understand—” Gundersen paused, struggling to regain control. More quietly he said, “Forgive me if I have intruded. Have I interrupted your rebirth’s beginning?”

“I have several days yet,” the sulidor said. “I merely prepare the chamber now.”

“And you’ll come forth from it as a nildor.”

“Yes. Over and over, rebirth after rebirth.”

“Life goes in a cycle here, then? Sulidor to nildor to sulidor to nildor to—”

“Yes. Over and over, rebirth after rebirth.”

“All nildoror spend part of their lives as sulidoror? All sulidoror spend part of their lives as nildoror?”

“Yes. All.”

How had it begun, Gundersen wondered? How had the destinies of these two so different races become entangled? How had an entire species consented to undergo such a metamorphosis? He could not begin to understand it. But he knew now why he had never seen an infant nildor or sulidor. He said, “Are young ones of either race ever born on this world?”

“Only when needed as replacements for those who can be reborn no more. It is not often. Our population is stable.”

“Stable, yet constantly changing.”

“Through a predictable pattern of change,” said Na-sinisul. “When I emerge, I will be Fi’gontor of the ninth birth. My people have waited for thirty turnings for me to rejoin them; but circumstances required me to remain this long in the forest of the mists.”

“Is nine rebirths unusual?”

“There are those among us who have been here fifteen times. There are some who wait a hundred turnings to be called once. The summons comes when the summons comes: And for those who merit it, life will have no end.”

“No — end—”

“Why should it?” Na-sinisul asked. “In this mountain we are purged of the poisons of age, and elsewhere we purge ourselves of the poisons of sin.”

“On the central plateau, that is.”

“I see you have spoken with the man Cullen.”

“Yes,” Gundersen said. “Just before his — death.”

“I knew also that his life was over,” said Na-sinisul. “We learn things swiftly here.”

Gundersen said, “Where are Srin’gahar and Luu’khamin and the others I traveled with?”

“They are here, in cells not far away.”

“Already in rebirth?”

“For some days now. They will be sulidoror soon, and will live in the north until they are summoned to assume the nildor form again. Thus we refresh our souls by undertaking new lives.”

“During the sulidor phase, you keep a memory of your past life as a nildor?”

“Certainly. How can experience be valuable if it is not retained? We accumulate wisdom. Our grasp of truth is heightened by seeing the universe now through a nildor’s eyes, now through a sulidor’s. Not in body alone are the two forms different. To undergo rebirth is to enter a new world, not merely a new life.”

Hesitantly Gundersen said, “And when someone who is not of this planet undergoes rebirth? What effect is there? What kind of changes happen?”

“You saw Kurtz?”

“I saw Kurtz,” said Gundersen. “But I have no idea what Kurtz has become.”

“Kurtz has become Kurtz,” the sulidor said. “For your kind there can be no true transformation, because you have no complementary species. You change, yes, but you become only what you have the potential to become. You liberate such forces as already exist within you. While he slept, Kurtz chose his new form himself. No one else designed it for him. It is not easy to explain this with words, Edmundgundersen.”

“If I underwent rebirth, then, I wouldn’t necessarily turn into something like Kurtz?”

“Not unless your soul is as Kurtz’s soul, and that is not possible.”

“What would I become?”

“No one may know these things before the fact. If you wish to discover what rebirth will do to you, you must accept rebirth.”

“If I asked for rebirth, would I be permitted to have it?”

“I told you when we first met,” said Na-sinisul, “that no one on this world will prevent you from doing anything. You were not stopped as you ascended the mountain of rebirth. You were not stopped when you explored these chambers. Rebirth will not be denied you if you feel you need to experience it.”

Easily, serenely, instantly, Gundersen said, “Then I ask for rebirth.”

SILENTLY, UNSURPRISED, Na-sinisul leads him to a vacant cell and gestures to him to remove his clothing. Gundersen strips. His fingers fumble only slightly with the snaps and catches. At the sulidor’s direction, Gundersen lies on the floor, as all other candidates for rebirth have done. The stone is so cold that he hisses when his bare skin touches it. Na-sinisul goes out. Gundersen looks up at the glowing fungoids in the distant vault of the ceiling. The chamber is large enough to hold a nildor comfortably; to Gundersen, on the floor, it seems immense.

Na-sinisul returns, bearing a bowl made from a hollow log. He offers it to Gundersen. The bowl contains a pale blue fluid. “Drink,” says the sulidor softly.

Gundersen drinks.

The taste is sweet, like sugar-water. This is something he has tasted before, and he knows when it was: at the serpent station, years ago. It is the forbidden venom. He drains the bowl, and Na-sinisul leaves him.

Two sulidoror whom Gundersen does not know enter the cell. They kneel on either side of him and begin a low mumbling chant, some sort of ritual. He cannot understand any of it. They knead and stroke his body; their hands, with the fearful claws retracted, are strangely soft, like the pads of a cat. He is tense, but the tension ebbs. He feels the drug taking effect now: a thickness at the back of his head, a tightness in his chest, a blurring of his vision. Na-sinisul is in the room again, although Gundersen did not see him enter. He carries a bowl.

“Drink,” he says, and Gundersen drinks.

It is another fluid entirely, or perhaps a different distillate of the venom. Its flavor is bitter, with undertastes of smoke and ash. He has to force himself to get to the bottom of the bowl, but Na-sinisul waits, silently insistent, for him to finish it. Again the old sulidor leaves. At the mouth of the cell he turns and says something to Gundersen, but the words are overgrown with heavy blue fur, and will not enter Gundersen’s ears. “What did you say?” the Earthman asks. “What? What?” His own words sprout leaden weights, teardrop-shaped, somber. They fall at once to the floor and shatter. One of the chanting sulidoror sweeps the broken words into a corner with a quick motion of his tail.

Gundersen hears a trickling sound, a glittering spiral of noise, as of water running into his cell. His eyes are closed, but he feels the wetness swirling about him. It is not water, though. It has a more solid texture. A sort of gelatin, perhaps. Lying on his back, he is several centimeters deep in it, and the level is rising. It is cool but not cold, and it insulates him nicely from the chill rock of the floor. He is aware of the faint pink odor of the inflowing gelatin, and of its firm consistency, like the tones of a bassoon in its deepest register. The sulidoror continue to chant. He feels a tube sliding into his mouth, a sleek piccolo-shriek of a tube, and through its narrow core there drips yet another substance, thick, oily, emitting the sound of muted kettledrums as it hits his palate. Now the gelatin has reached the lower curve of his jaw. He welcomes its advance. It laps gently at his chin. The tube is withdrawn from his mouth just as the flow of gelatin covers his lips. “Will I be able to breathe?” he asks. A sulidor answers him in cryptic Sumerian phrases, and Gundersen is reassured.