But after a long, long time there were scratching sounds. Still later, pantings. Then Calhoun's head came up, snow-covered, over the edge of the crevasse into which he'd tumbled. He rested, panting. Then, desperately, he managed to crawl to where snow was waist-deep but the ground proven solid by his previous footprints. He staggered upright. He stumbled to the ship. Very, very wearily, he climbed to the lock door. Murgatroyd embraced his legs, making a clamor of reproachful rejoicing that after going away he had come back.
"Quit it, Murgatroyd," said Calhoun wearily. "I'm back, and I'm all right. He's not. He was underneath when we landed, thirty feet down. I heard his skull crack when we hit. He's dead. If he hadn't been, how I'd have gotten him up again I don't know, but he was dead. No question."
Murgatroyd said agitatedly, "Chee! Chee-chee!"
Calhoun closed the lock doors. There was a nasty rock scrape across his forehead. He looked like a man of snow. Then he said heavily, "He could have told me what I need to know! He could have told me how they make the plagues work! He could have helped me finish the whole business in a hurry, when there are men dying of it. But he didn't believe I'd actually do anything to him. Stupid! It's insane!"
He began to brush snow off of himself, with an expression of such sickish bitterness on his face as was normal for a Med Ship man—whose business it is to keep people from dying—when he realized that he had killed a man.
Murgatroyd went padding across the control-room. He swarmed up to where Calhoun kept the crockery. He jumped down to the floor again. He pressed his private, tiny coffee cup upon Calhoun.
"Chee!" said Murgatroyd agitatedly. "Chee-chee! Chee!"
He seemed to feel that if Calhoun made coffee, that all matters would be returned to normal and distressing memories could be cast aside. Calhoun grimaced.
"If I died you'd have no coffee, eh? All right, as soon as we're on course for Kryder II I'll make you some. But I think I've blundered. I tried to act like a detective instead of a medical man because it should have been quicker. I'll make some coffee in a little while."
He seated himself in the pilot's chair, glanced over the instrument readings, and presently pressed a button.
The Aesclipus Twenty lifted from her landing place, her rockets lighting the icy stone spires of the island with an unearthly blue-white flame. The speed of her rising increased. A little later, there was only a dwindling streak of rocket fire ascending to the stars.
IV
The crescent which was the planet Kryder II enlarged gradually, with the sun many millions of miles beyond it. The Aesclipus Twenty swung in its course, pointing at a right angle to the line along which it had been moving. Its drive-baffles glowed faintly as the Lawlor interplanetary drive gave it a new impetus, changing its line of motion by adding velocity in a new direction to the sum of all the other velocities it had acquired. Then the ship swung back, not quite to its former bearing but along the line of its new course.
Inside the ship, Calhoun again aimed the ship. He used the sighting circle at the very center of the dead-ahead vision screen. He centered a moderately bright star in that glowing circle. The star was a certain number of seconds of arc from the planet's sunlit edge. Calhoun watched. All about, in every direction, multitudes of shining specks—actually suns—floated in space. Many or most of them warmed their families of planets with the solicitude of brooding hens. Some circled each other in stately, solemn sarabands. There were some, the Cepheids, which seemed to do neither but merely to lie in emptiness, thin and gaseous, pulsating slowly as if breathing.
Calhoun relaxed, satisfied. The guide star remained at exactly the same distance from the crescent planet, while the Med Ship hurtled toward it. This arrangement was a standard astrogational process. If the moving planet and the sighting star remained relatively motionless, the total motion of the Med Ship was exactly adjusted for approach. Of course, when close enough the relationship would change, but if the ship's original line was accurate, the process remained a sound rule-of-thumb method for approaching a planet.
The Med Ship sped on. Calhoun, watching, said over his shoulder to Murgatroyd, "We're pretty much in the dark about what's going on, Murgatroyd, not in the matter of the plague, of course. That's set up to be ended by somebody arriving in a Med Ship, as in two cases before this one. But if they can end it, they needn't have started it. I don't like the idea of anything like this being unpunished."
Murgatroyd scratched reflectively. He could see the vision screens. He could have recognized buildings as such, though probably not as individual ones. On the screens, save for the sun and one crescent planet, there were only dots of brightness of innumerable colorings. To Murgatroyd, who spent so much of his life in space travel, the stars had no meaning whatever.
"Technically," observed Calhoun, "since medicine has become a science, people no longer believe in plague-spreaders. Which makes spreading plagues a possible profession." *
Murgatroyd began to clean his whiskers, elaborately licking first the right-hand and then the left-hand ones.
Calhoun again checked the relative position of the sighting star and Kryder II. He brought up a file on the computer. It was a resume of the history of toxicology. He hunted busily for items having to do with the simulation of bacterial toxins by inorganic compounds. He made notes, not many. He consulted another file. It dealt with antigens and antibodies. He made more notes and consulted a third file.
He worked carefully with pencil and paper and then, with his memos at hand, Calhoun set the computer to find the known compounds with such-and-such properties, a boiling point above so-and-so, with an inhibitive effect upon the formation of certain other compounds.
He went back to the pilot's chair. The crescent world was noticeably nearer and larger. Calhoun became absorbed in the delicate task of putting the Med Ship in suitable orbit around Kryder II. The ship obeyed him. It swung around to the green world's sunlit hemisphere. He addressed the communicator microphone:
"Med Ship Aesclipus Twenty calling ground to report arrival and ask coordinates for landing. Our mass is fifty standard tons. Repeat, five-oh tons. Purpose of landing . . . response to planetary health department request for service."
Calhoun watched as more of the surface of the nearing planet came into view with the Med Ship's swing around it. There were bright green continents, showing irregular streaks of white glaciation where mountain ranges rose. There were seas and oceans and cloud masses and that filmy blue haze at the horizon which so much surprised the first explorers of space.
"Med Ship Aesclipus—" Calhoun's recorded voice repeated the call. Murgatroyd popped his head out of his personal cubbyhole. When Calhoun talked, but not to him, it meant that presently there would be other people around. And people did not long remain strangers to Murgatroyd. He made friends with ease and zest. Except for Calhoun, Murgatroyd defined friends as people who gave him sweet cakes and coffee.
The communicator speaker said, "Calling Med Ship! Ground calling Med Ship! Coordinates are . . ." the voice named them. It sounded warm and even rejoicing through the speaker, as if the landing-grid operator had a personal interest in the arrival of a man sent by the Interstellar Medical Service. "We're plenty glad you've come, sir! Plenty glad! Did you get the coordinates? They're . . ."