Her eyes snapped open.
She turned on the overflow fluoro and went to the computer. It was made no differently from the other portables. Donli had used it. But she could not look away from the unique scratches and bumps on that square case, as she could not escape his microscope, chemanalyzers, chromosome tracer, biological specimens… She seated herself. A drink would have been very welcome, except that she needed clarity. “Activate!” she ordered.
The On light glowed yellow. Evalyth tugged her chin, searching for words. “The objective,” she said at length, “is to trace a lowlander who has consumed several kilos of flesh and blood from one of this party, and afterward vanished into the jungle. The killing took place about sixty hours ago. How can he be found?”
The least hum answered her. She imagined the links; to the maser in the ferry, up past the sky to the nearest orbiting relay unit, to the next, to the next, around the bloated belly of the planet, by ogre sun and inhuman stars, until the pulses reached the mother ship; then down to an unliving brain that routed the question to the appropriate data bank; then to the scanners, whose resonating energies flew from molecule to distorted molecule, identifying more bits of information than it made sense to number, data garnered from hundreds or thousands of entire worlds, data preserved through the wreck of Empire and the dark ages that followed, data going back to an Old Earth that perhaps no longer existed. She shied from the thought and wished herself back on dear stem Kraken.
“Query,” said the artificial voice. “Of what origin was the victim of this assault?”
Evalyth had to wet her lips before she could reply: “Atheian. He was Donli Sairn, your master.”
“In that event, the possibility of tracking the desired local inhabitant may exist. The odds will now be computed. In the interim, do you wish to know the basis of the possibility?”
“Y-yes.”
“Native Atheian biochemistry developed in a manner quite parallel to Earth’s,” said the voice, “and the early colonists had no difficulty in introducing terrestrial species. Thus they enjoyed a friendly environment, where population soon grew sufficiently large to obviate the danger of racial change through mutation and/or genetic drift. In addition, no selection pressure tended to force change. Hence the modern Atheian human is little different from his ancestors of Earth, on which account his physiology and biochemistry are known in detail.
“This has been essentially the case on most colonized planets for which records are available. Where different breeds of men have arisen, it has generally been because the original settlers were highly selected groups. Randomness, and evolutionary adaptation to new conditions, have seldom produced radical changes in biotype. For example, the robustness of the average Krakener is a response to comparatively high gravity; his size aids him in resisting cold, his fair complexion is helpful beneath a sun poor in ultraviolet. But his ancestors were people who already had the natural endowments for such a world. His deviations from their norm are not extreme. They do not preclude his living on more Earth-like planets or interbreeding with the inhabitants of these.
“Occasionally, however, larger variations have occurred. They appear to be due to a small original population or to unterrestroid conditions or both. The population may have been small because the planet could not support more, or have become small as the result of hostile action when the Empire fell. In the former case, genetic accidents had a chance to be significant; in the latter, radiation produced a high rate of mutant births among survivors. The variations are less apt to be in gross anatomy than in subtle endocrine and enzymatic qualities, which affect the physiology and psychology. Well known cases include the reaction of the Gwydiona to nicotine and certain indoles, and the requirement of the Ifrians for trace amounts of lead. Sometimes the inhabitants of two planets are actually intersterile because of their differences.
“While this world has hitherto received the sketchiest of examinations—” Evalyth was yanked out of a reverie into which the lecture had led her. “—certain facts are clear. Few terrestrial species have flourished; no doubt others were introduced originally, but died off after the technology to maintain them was lost. Man has thus been forced to depend on autochthonous life for the major part of his food. This life is deficient in various elements of human nutrition. For example, the only Vitamin C appears to be in immigrant plants; Saim observed that the people consume large amounts of grass and leaves from those species, and that fluoroscopic pictures indicate this practice has measurably modified the digestive tract. No one would supply skin, blood, sputum, or similar samples, not even from corpses.”
“The calculations are now complete.” As the computer resumed, Evalyth gripped the arms of her chair and could not breathe. “While the answer is subject to fair probability of success. In effect, Atheian flesh is alien here. It can be metabolized, but the body of the local consumer will excrete certain compounds, and these will import a characteristic odor to skin and breath as well as to urine and feces. The chance is good that it will be detectable by neo-Freeholder technique at distances of several kilometers, after sixty or seventy hours. But since the molecules in question are steadily being degraded and dissipated, speed of action is recommended.”
I
“Shall the organisms be ordered for you and given the appropriate search program?” asked the voice. “They can be on hand in an estimated three hours.”
“Yes,” she stammered. “Oh, please—Have you any other… other… advice?”
“The man ought not to be killed out of hand, but brought here for examination, if for no other reason, that in order that the scientific ends of the expedition may be served.”
The single big moon rose nearly full, shortly after sundown. It drowned most stars; the jungle beneath was cobbled with silver and dappled with black; the snowcone of Mount Bums floated unreal at the unseen edge of the world. Wind slid around Evalyth where she crouched on her gravsled; it was full of wet acrid odors, and felt cold though it was not, and chuckled at her back. Somewhere something screeched, every few minutes, and something else cawed reply.
She scowled at her position indicators, aglow on the control panel. Curses and chaos, Moru had to be in this area! He could not have escaped from the valley on foot in the time available, and her search pattern had practically covered it. If she ran out of bugs before she found him, must she assume he was dead? They ought to be able to find his body regardless, ought they not? Unless it was buried deep. Here. She brought the sled to hover, took the next phial off the rack, and stood up to open it.
The bugs came out many and tiny, like smoke in the moonlight. Another failure?
No! Wait! Were not those motes dancing back together, into a streak barely visible under the moon, and vanishing downward? Heart thuttering, she turned to the indicator. Its neurodetector antenna was not aimlessly wobbling, but pointed straight west-northwest, declination thirty-two degrees below horizontal. Only a concentration of the bugs could make it behave like that. And only the particular mixture of molecules to which the bugs had been presensitized, in several parts per million or better, would make them converge on the source.
“Ya-a-ah!” She couldn’t help the one hawk-yell. But thereafter she bit her lips shut—blood trickled unnoticed down her chin—and drove the sled in silence.
The distance was a mere few kilometers. She came to a halt above an opening in the forest. Pools of scummy water gleamed in its rank growth. The trees made a solid-seeming wall around. Evalyth clapped her night goggles down off her helmet and over her eyes. A lean-to became visible. It was hastily woven from vines and withes, huddled against a pair of the largest trees to let their branches hide it from the sky. The bugs were entering.
Evalyth lowered her sled to a meter off the ground and got to her feet again. A stun pistol slid from its sheath into her right hand. Her left rested on the blaster.
Mom’s two sons groped from the shelter. The bugs whirled around them, a mist that blurred their outlines. Of