MED SERVICE BY MURRAY LEINSTER Illustrated by van Dongen [Transcriber's Note: This etext was produced from Astounding Science Fiction August 1957. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] I "The probability of unfavorable consequences cannot be zero in any action of common life, but the probability increases by a very high power as a series of actions is lengthened. The effect of moral considerations, in conduct, may be stated to be a mathematically verifiable reduction in the number of unfavorable possible chance happenings. Of course, whether this process is termed the intelligent use of probability, or ethics, or piety, makes no difference in the fact. It is the method by which unfavorable chance happenings are made least probable. Arbitrary actions such as we call criminal cannot ever be justified by mathematics. For example ..." _Probability and Human Conduct_ Fitzgerald Calhoun lay in his bunk and read Fitzgerald on "Probability and Human Conduct" as the little Med Ship floated in overdrive. In overdrive travel there is nothing to do but pass the time away. Murgatroyd, the _tormal_, slept curled up in a ball in one corner of the small ship's cabin. His tail was meticulously curled about his nose. The ship's lights burned steadily. There were those small random noises which have to be provided to keep a man sane in the dead stillness of a ship traveling at thirty times the speed of light. Calhoun turned a page and yawned. Something stirred somewhere. There was a click, and a taped voice said: "_When the tone sounds, break-out will be five seconds off._" A metronomic ticking, grave and deliberate, resounded in the stillness. Calhoun heaved himself up from the bunk and marked his place in the book. He moved to and seated himself in the control chair and fastened the safety belt. He said: "Murgatroyd! Hark, hark the lark in Heaven's something-or-other doth sing. Wake up and comb your whiskers. We're getting there." Murgatroyd opened one eye and saw Calhoun in the pilot's chair. He uncurled himself and padded to a place where there was something to grab hold of. He regarded Calhoun with bright eyes. "_BONG!_" said the tape. It counted down. "Five--four--three--two--one--" It stopped. The ship popped out of overdrive. The sensation was unmistakable. Calhoun's stomach seemed to turn over twice, and he had a sickish feeling of spiraling dizzily in what was somehow a cone. He swallowed. Murgatroyd made gulping noises. Outside, everything changed.