It was broad daylight when he'd finished the horribly tedious detail work the problem had required. In fact, it was close to sundown. He said tiredly to Murgatroyd, "Well, we've got it!"
Murgatroyd did not answer. Calhoun did not notice for a moment or so. Then he jerked his head about.
Murgatroyd lay on the Med Ship floor, his eyes half-closed. His breath came in quick, shallow pantings.
He'd eaten coffeebeans when they fell on the floor of the control-room. Calhoun picked him up, his lips angrily compressed. Murgatroyd neither resisted nor noticed. Calhoun examined him with a raging, painstaking care.
Murgatroyd was ill. He came of a tribe which was never sick of any infectious disease; they reacted with explosive promptness to any trace of contagion and produced antibodies which would destroy any invading pathogen. His digestive system was normally no less efficient, rejecting any substance which was unwholesome. But the toxic compound which caused the plague on Kryder II was not unwholesome in any direct sense. It did not kill anybody, by itself. It simply inhibited, it prevented, the formation of those antibodies which are a creature's defense against disease.
Murgatroyd had a fully developed case of pneumonia. It had developed faster in him than in a human being. It was horribly more severe. He'd developed it from some single diplococcus pneumonia upon his fur, or perhaps on Calhoun's garments, or possibly from the floor or wall of the Med Ship. Such microorganisms are everywhere. Humans and animals are normally immune to any but massive infection. But Murgatroyd was at the very point of death from a disease his tribe normally could not—could not!—contract.
Calhoun made the tests required to make him absolutely certain. Then he took his new solution and prepared to make use of it.
"Fortunately, Murgatroyd," he said grimly, "we've something to try for this situation. Hold still!"
VI
Murgatroyd sipped a cup of coffee with infinite relish. He finished it. He licked the last drop. He offered it to Calhoun and said inquiringly, "Chee?"
"It probably won't hurt you to have one more cup," said Calhoun. He added irrelevantly, "I'm very glad you're well, Murgatroyd!"
Murgatroyd said complacently, "Chee-chee!"
Then the space communicator said metallically, "Calling Med Ship! Calling Med Ship! Calling Med Ship Aesclipus Twenty! Ground calling Aesclipus Twenty!"
The Med Ship was then in orbit around Kryder II. It was a sound, high orbit, comfortably beyond atmosphere. Calhoun was officially waiting for word of how his communication and instruction to the authorities aground had turned out. He said, "Well?"
"I'm the Planetary Health Minister," said a voice. Somehow it sounded infinitely relieved. "I've just had reports from six of our hospitals. They check with what you told us. The paramecia test works. There were a number of different foods—ah—contaminated at their packaging points, so that even if someone had identified one food as the cause of the plague in one place, in another area it wouldn't be true. It was clever! It was damnably clever! And of course we've synthesized your reagent and tried it on laboratory animals we were able—by your instructions—to give the plague."
"I hope," said Calhoun politely, "that the results were satisfactory."
The other man's voice broke suddenly.
"One of my children . . . he will probably recover, now. He's weak. He's terribly weak! But he'll almost certainly live, now that we can protect him from reinfection. We've started planet-wide use of your reagent."
"Correction," said Calhoun. "It's not my reagent. It is a perfectly well-known chemical compound. It's not often used, and perhaps this is its first use medically, but it's been known for half a century. You'll find it mentioned . . ."
The voice at the other end of the communication link said fiercely, "You will excuse me if I say nonsense! I wanted to report that everything you've told us has proved true. We have very many desperately ill, but new patients have already responded to medication to counter the—contamination of food they'd taken. They've gotten thoroughly well of normal disease and haven't developed others. Our doctors are elated. They are convinced. You can't have any idea how relieved . . ."
Calhoun glanced at Murgatroyd and said dryly, "I've reason to be pleased myself. How about Doctor Kelo and his friends?"
"We'll get him! He can't get off the planet, and we'll find him! There's only one ship aground at the spaceport; it came in two days ago. It's stayed in port under self-quarantine at our request. We've instructed it not to take anyone aboard. We're chartering it to go to other planets and buy foodstuffs to replace the ones we're testing and destroying."
Calhoun, stroking Murgatroyd, said more dryly than before, "I wouldn't. You'd have to send currency to pay for the stuff you want to import. On two previous occasions very, very large sums gathered for that purpose have disappeared. I'm no policeman but that could be the reason for the plague. There are some people who might start a plague for the express purpose of being entrusted with some scores of millions of credits . . ."
There was silence at the other end of the conversation. Then a man's voice, raging, "If that's it!"
Calhoun broke in.
"In my orbit I'll be below your horizon in minutes. I'll call back. My orbit's very close to two hours duration."
"If that's it," repeated the voice, raging, "We'll . . ."
There was silence. Calhoun said very cheerfully, "Murgatroyd, I'm good at guessing the way a relatively honest man's mind works. If I'd told them earlier that the plague victims were murdered, they'd have discounted the rest of what I had to say. But I'm learning the way a criminal's mind works too! It takes a criminal to think of burning down a house to cover up the fact that he robbed it. It takes a criminal to think of killing a man for what he may carry in his pockets. It would take a criminal to start a plague so he can gather money to steal, under the pretense that he's going to use it to buy unpoisoned food to replace the food he's poisoned. I had trouble understanding that!"
Murgatroyd said, "Chee!"
He got up. He walked in a rather wobbly fashion as if testing his strength. He came back and nestled against Calhoun. Calhoun petted him. Murgatroyd yawned. He'd been weakened by his illness. He still didn't understand it. Tormals are not accustomed to being ill.
"Now," said Calhoun reflectively, "I make a guess at how certain criminal minds will work if they eavesdropped just then. We've spoiled their crime on Kryder II. They'd put a lot of time and trouble into committing it. Now they've had their trouble and committed their murders for nothing. I think, I think they'll be angry. With me."
He settled Murgatroyd comfortably. He went about the ship stowing things away. The samples of ditch water and of foodstuffs he placed so no shock or sudden acceleration could spill them. He made sure there were no loose objects about the control-room. He went down below and made especially sure that the extra plastic-sealed control-central unit was properly stowed, and that the spacesuit worn by one of the two men to board the Med Ship at breakout was suitably held fast. They'd be turned over to the laboratories at headquarters. If carefully disassembled the control-central unit would give positive proof that a certain man in the headquarters technical staff had installed it. Suitable measures would be taken. The spacesuit would identify the man now at the bottom of a rocky crevasse on an icy, uninhabited world.