"Exactly!" said Calhoun. "This bug is comatose on Delhi, where there is no plague. It's wildly active on Lanke, where there has been, can be, and probably already is plague. We'll return these bugs to a Lanke environment."
He made it, distilled water and a nutrient substance for them to feed on. It was practically the environment of Lanke. He returned the just-made-comatose microbes to the sort of environment in which plague germs throve. These microbes regained all the enthusiasm of multiplication and dancing and—doubtless—the production of deadly toxins they'd shown before.
"Something on Delhi," said Calhoun, "slows down their activity and reduces their breeding rate as something on other worlds keeps the bigger predators from getting too numerous. Something here keeps their numbers down, and that something doesn't, on Lanke. What would you guess, Murgatroyd?"
Murgatroyd said, "Chee!" He moved about the lab table, with a very fine air of someone checking the various bits of equipment there. He picked up a culture slide. He sniffed at it and said, "Chee-chee!" in a very disapproving manner. He dropped it, and swamp water spilled. The odor was actively unpleasant. Murgatroyd sneezed, and retreated from it. He said, "Chee!" and rubbed his nose vigorously.
Calhoun shrugged. He mopped up the spilled half-spoonful. He had visions of living on a world where soil and swamp water stank when disturbed, and where even sea water might do the same. Where one boiled water before drinking it, not to make it germ-free but to drive out most of the taste. Elna had tasted normal water and had told Rob bitterly that she'd never taste water again without remembering how that pure water tasted.
He looked at the vision screens. There were fluffy white clouds in the bluest of blue skies. All oxygen atmosphere planets have blue skies, and those with habitability-one temperatures have winds and jet-streams and storm patterns of strictly standard types. On all the worlds with vegetation there were the equivalents of trees and brushwood and grass. The look of Delhi was not repellent, if one could only get used to the smell of the atmosphere, and not of the soil—if the reek of the swamp was simply an exaggeration of what everything smelled like and one could never fail to notice it . . . the passionate desire of its people to leave it could be understood.
The first log was almost at the Med Ship. A second was on the way. Smaller groups were bringing shorter logs. There were men coming with coils of rope.
Calhoun regarded them detachedly. He saw a man stumble and fall, and get up and be sick because of the stench of the mud he'd disturbed.
Calhoun went back to his work. He set out minute samples of swamp water, and added infinitesimal dosages of reagents to each, and then still more minute quantities of the Lanke environment, frantically active culture. Then a check to see what substance—or what substances made up a group—removed by a reagent would allow the spheres to thrive in swamp water.
It could almost have been predicted that the elaborate setup for research would be useless, and something insanely simple would give the answer. A strip of filter paper, wetted with the active culture and in a stoppered bottle with a trace of swamp fluid, that showed the active culture stopped dead. It did not touch swamp water. It was exposed only to the reekuotee stench, the effluvium of the swamp. Calhoun said, "The devil!" Painstakingly, he repeated the test. He wanted to talk about it, to explain it for his own hearing so that he'd know if his reasoning made sense. He said, "Murgatroyd!"
Murgatroyd said with an air of charmed interest, "Chee?"
"I've got it," said Calhoun. "There is something in the swamp water that slows up the plague germs in multiplying and producing toxin to kill us humans. It's an inhibitive factor like the factors that on different worlds make large carnivores breed slowly, because if they bred fast they'd wipe out their own food supply and die of starvation. In the micro-ecology of germs in Delhi, there's something that holds down plague germs so nobody can get the plague. But on Lanke that inhibitive factor's missing."
Murgatroyd said, "Chee!" and, beady-eyed, watched Calhoun's face.
"I'll bet you a hogshead of coffee to a cookie," said Calhoun exuberantly, "that it's nothing but the smell, the reek, the stink of that—Ha!" He referred to the Stellar Directory. He found Delhi. "Here it is! There's a methane derivative to point oh four percent in the planet's air, about the same as carbon dioxide. Maybe there's a bug in the ocean that produces it. Maybe—oh, anything! There are microbes that can't live where there's oxygen and others that can't live where it isn't. This is a microbe that can just barely live where there's point oh four percent of this stinking stuff. But it goes wild where there's . . . now! You see, Murgatroyd? A ship from here, with Delhi air, could go to Lanke and nobody'd have the plague. But a man from it would develop the plague when he got out into Lanke air which hasn't the methane that holds the plague-germ back. A ship from Lanke that left Delhi without Delhi air in its reserve tanks . . . everybody aboard would die of the plague on the way home. You see?"
Murgatroyd said, "Chee!"
The girl Elna said uneasily, "They're setting up some sort of—thing made out of the logs."
Calhoun looked. There was no battering ram support being erected. There were two short logs upright, and heavy logs crosswise, and a very long log with numerous cross-pieces fastened to it lying in the disturbed ground. Men were working with ropes. It couldn't make an effective battering ram. However, Calhoun was much too elated to give thought to the engineering feat in progress outside. He wanted to verify what was at once plausible and lacking proof. Proof would be finding a highly volatile liquid or a condensable gas in solution in the swamp water. He most definitely had the equipment for seeking it. He used his swamp-water sample recklessly. He did a reduced-pressure fractionating still-run, which could take a full tablespoon full of swamp water and by precise control of the temperature and pressure draw off dissolved air, dissolved carbon dioxide, dissolved . . .
He got enough of a condensable vapor to be visible under the microscope. With the beautifully exact temperature control he had, he found its boiling point by watching that infinitesimal droplet disappear as vapor, and recondense as a fluid as he sent the temperature up and down, watching through a microscope.
Elna said uneasily, "They're getting ready to do something . . .
Calhoun looked at the screen. Men swarmed about an area twenty or thirty feet from the Med Ship's outer plating. They had ropes fastened here and there. They were arranging themselves in long rows about the ropes. There were hundreds of them preparing to do something with the logs. Away over at the edge of the slanting ground, there was much smoke. Men worked at something involving fire. Men shook their fists at the Med Ship, ready to grasp and haul on the ropes they'd brought and placed.
Calhoun blinked. Then he said, "Clever! That's really a beautiful trick! They're sure we can't lift off, so they're going to take the ship with the minimum of damage . . . That's really brilliant!"
Rob said fiercely, "When are you going to start smashing the ship?"
"I've much more important things to do," said Calhoun. "Much more important!"
Almost hilariously, he threw the G.C. switch and began to calclass="underline" "General call! General call! To repaired lifeboat. Med Ship Aesclipus Twenty calling repaired lifeboat! Top emergency! Come in, repaired lifeboat!"
As he called, he regarded the work outside, which now approached a climax of activity. Men were making sure that ropes lying on the marshy ground were exactly laid to be pulled on. Other men were lining up to haul on those ropes. Leaders arranged them exactly to get the maximum of traction in exactly the proper directions-of-pull. A group of men were bringing something which gave off a thick white smoke. They kept out of the smoke.