The Pak breeders were Homo habilis, and they were ancestors of the human race, which could eat things that would make a dog go blind. They could eat dogs, for that matter. Protectors weren't limited to eating tree-of-life, as Brennan called it; it was just what they needed to keep regenerating, and digesting disease germs, and so forth. Some of them must have lasted centuries.
When Brennan had been telling this fable, he had already made his plans to steal a Pak Protector's ramship and convince the UN ARM that he was doomed. They wouldn't interfere with his manipulation of human society if they didn't believe he existed. On the trip back to Brennan's ship, from which Phssthpok had kidnapped him before realizing he was family, Brennan had refused to allow one of his companions, Lucas Garner, to smoke, on the grounds that he, Brennan, had to act to keep the man healthy. This was well after the time of Pasteur, so it was known by then that a viral disease such as cancer could not be contracted by smelling burning leaves; Brennan had been ensuring that the 184-year-old paranoid would be too exasperated to think things through.
Peace deduced the rest.
The Protectors had gone out in fission-powered ion-drive ships, looking for planets where tree-of-life would grow properly. They had found none; there were few planets that were at all habitable. However, the original expedition would have been equipped for terraforming. Planets had water added, were seeded with algae, were even smashed with small moons to create high ground on the far side, above the thick atmosphere. Meanwhile, the few Protectors that remained on Earth were cultivating mutations, so that a species would eventually arise which would be able to use the terraformed planets.
And some explorers must have met the puppeteers.
Two and a half million years back, the puppeteers must have already had spaceflight-not manned, to be sure, but effective at searching for threats. The Protectors would have realized that their limited numbers could never exterminate the puppeteers before Earth's breeder population was found and slaughtered. The Protectors wouldn't have returned to Earth, and they would have killed themselves rather than risk giving away its location. At least one must have made sure of being undiscovered, though, and returned to Earth to warn the Protectors there; and they in turn would have methodically destroyed all signs of technological development. Except the plants they'd modified to produce a multipurpose raw material, unnecessary to the plants' survival, in their secretions; there were too many of those, intended for availability in all climates, to hunt them all down. The best-known was the rubber tree, so useful it was still cultivated on Earth.
The puppeteers had eventually found Earth, and Kzin, and a lot of less interesting inhabited planets. They had manipulated the two dangerous races' development. When Phssthpok, another Pak protector, had come from the Core, they'd let him through, to stimulate Earth's technology to catch up with Kzin's.
But, thanks to a couple of centuries of Brennan's interference, Earth developed wrong, becoming too peaceful to survive the discovery of the planet by the kzinti. So the puppeteers had arranged to let kzinti warcraft find human colony ships in interstellar space-something that had happened half a dozen times. Twice, human ships had survived long enough to send home messages about the contacts.
And humans and kzinti alike thought of it as coincidence!
Picture a globe six million miles across, full of air but unilluminated. Add hundreds of floating bonfires, each with a surface area of at least an acre, in all colors, well-scattered. Imagine air jets to push you from one bonfire to another, in straight lines. Now picture other people, all coming from one bonfire you haven't been to, traveling to various others you haven't been to, propelled by butane-jet cigarette lighters. You know nothing of cigarette lighters and do not use instruments designed to seek them out. How close do you have to get to one to notice it against the background of bonfires? The closest that two of these skew paths get to each other is in excess of a thousand miles. Now multiply the distances by 40 million, and the bonfire surfaces by 1.6 quadrillion, and ask yourself how the kzinti found human ships in interstellar space six times.
Once would be a miracle to stupefy an atheist. Twice is enemy action. Six times is policy.
The puppeteers had arranged beacons, not recognizable as such, to attract kzinti ships. (Possibly telepathic; the kzinti had the capability far more often than humans, which implied it was latent in the whole species-which would explain why they were so hostile: noise.) Once the First War began, the puppeteers had quickly realized that the human ability to kill anything had been all but bred out of the race, and the humans would lose; so they arranged for the Outsiders to go to We Made It, outside the war zone, and sell hyperdrive to the crashlanders. Probably without telling the Outsiders why. Conceivably without telling them at all-Outsiders followed starseeds, and it would be a simple matter to dump trace elements a starseed needed into a star's chromosphere.
And while the Outsiders were ambling along at sublight speeds, Wunderland's population was conquered, enslaved, and eaten.
The puppeteers were powerful and arrogant, which was understandable, but also shortsighted in their meddling, which was intolerable. It might be necessary to exterminate them. If so, it would first be necessary to get them far from human space, as they would doubtless panic and slaughter everything in sight once the procedure began. Doubtless they were aware of the possibility of higher levels of hyperdrive, the next of which was at (if the drive's manual of operation was based on the assumptions it seemed to be) 6! x4! x2!/10=3456 times the speed of the first level, or near enough to . 8 lightyears per minute. It was always profitable to go faster, so they would be doing research already, so she would only have to have a few algorithms published in technical journals to get them out of the blind alleys. A publicity trip to the Core would give them a look at whatever the Pak migration had been fleeing, and they'd run immediately. That would give Peace a few centuries to decide what to do with them.
The kzinti could be disposed of more promptly.
When Peace was too full to eat any more, she reprogrammed and partly rebuilt the autodoc, then got in for a full scan. Brennan had created a human-infecting form of the virus that changed the Pak (or their relatives) into Protectors, and he and his descendant Truesdale had brought it to Home, to prepare a surprise for the Pak Protector scouts they'd lured away from Earth. Peace needed to find out what it did. The results showed there were things Brennan hadn't mentioned, and that Truesdale most likely hadn't known.
Each lung had an extra lobe, now, so the right had four and the left three. The lobes were now separated by membranes, so that puncturing one wouldn't collapse the rest of the lung. Ribs had thickened and spread to accommodate the change. There was now a two-chamber iliac heart in the groin, drawing blood from the lower body. It pumped it directly into the new lung lobes, which oxygenated it and added it to the blood returning from the rest of the body. Running this mix through the original lungs produced blood supersaturated with oxygen, which the expanded brain needed desperately. The original heart developed thicker muscle and redundant feeder vessels, and the extra oxygen kept it from strain. The extra pass through the lungs would also allow her to function when the partial pressure of oxygen in local air was too low to keep an unchanged human conscious.
The lymphatic system had developed one-way valves, such as veins had, so that the fluid was kept circulating by changes in pressure as muscles were used. The spleen had developed into an organ much like the liver in texture, and its new function seemed to be scavenging trace minerals.
The end joint of each finger was now able to move independently of the rest of the finger, like the end of a human thumb.
There was a hard shell contained within each eyelid. The shell was resilient, and opaque. The eye itself had a second lens behind the original. The new lens was normally flat, but could be made concave enough for work as close as an inch from the pupil. The original lens was saturated with a substance which responded to chemical cues in milliseconds, to become tinted (the usual state), polarized, or clear. Without the Protector additives, this chemical turned the lens white, producing cataracts. (Brennan and Truesdale, products of Fertility Board selection, would have known nothing of this, and would sometimes have needed sunglasses.) The pupil could now open all the way to the edge of the iris, gathering far more light, and the retina had grown a tapetum, like a cat's eye, to give the receptors a second try at the photons. The progressive die-off of the retina's color-detecting rods was compensated by the trick of tinting the lenses different colors, providing strong contrast. It occurred to her that the instinctive attempt to see this degree of contrast, by unaltered elderly humans, finally explained gingham. The preprocessing layer of the retina was thicker, too; and as a huge amount of new brain growth had been in the optic center, image persistence was longer. A Protector could read a newspaper page held up twenty feet away if the light was good.
The olfactory region of the brain was now almost half as big as the optic center used to be. This, like the finger change, was implicit in Brennan's assertions; a Protector had to be able to distinguish one protein molecule from another when they differed by only one amino acid in one place. The processing involved was
