a different voice came from the speaker.

"Med Ship Aesclipus! Med Ship Aesclipus!"

Calhoun answered and the voice said anxiously;

"'Sorry about the challenge, but we have the blueskin problem always with us. We have to be extremely careful! Will you come in, please?"

"I'm on my way," said Calhoun.

"The planetary health authorities," said the voice, more anxiously still, "are very anxious to be coöperative. We need Med Service help! We lose a lot of sleep over the blueskins! Could you tell us the name of the last Med Ship to land here, and its inspector, and when that inspection was made? We want to look up the record of the event to be able to assist you in every possible way."

"He's lying," Calhoun told Murgatroyd, "but he's more scared than hostile."

He picked up the order-folio on Weald Three. He gave the information about the last Med Ship visit. He clicked off.

"What?" he asked, "is a blueskin?"

He'd read the folio on Weald, of course, but as the ship swam onward through emptiness he went through it again. The last medical inspection had been only perfunctory. Twelve years earlier—instead of three—a Med Ship had landed on Weald. There had been official conferences with health officials. There was a report on the birth-rate, the death-rate, the anomaly-rate, and a breakdown of all reported communicable diseases. But that was all. There were no special comments and no overall picture.

Presently Calhoun found the word in a Sector dictionary, where words of only local usage were to be found.

"Blueskin; Colloquial term for a person recovered from a plague which left large patches of blue pigment irregularly distributed over the body. Especially, inhabitants of Dara. The condition is said to be caused by a chronic, non-fatal form of Dara plague and has been said to be non-infectious, though this is not certain. The etiology of Dara plague has not fully been worked out. The blueskin condition is hereditary but not a genetic modification, as markings appear in non-Mendellian distributions...."

Calhoun puzzled over it. Nobody could have read the entire Sector directory, even with unlimited leisure during travel between solar systems. Calhoun hadn't tried. But now he went laboriously through indices and cross-references while the ship continued travel onward. He found no other reference to blueskins. He looked up Dara. It was listed as an inhabited planet, some four hundred years colonized, with a landing-grid and at the time the main notice was written out, a flourishing interstellar commerce. But there was a memo, evidently added to the entry in some change of editions.

"Since plague, special license from Med Service is required for landing."

That was all. Absolutely all.

The communicator said suavely;

"Med Ship Aesclipus Twenty! Come in on vision, please!"

Calhoun went to the control-board and threw on vision.

"Well, what now?" he demanded.

His screen lighted. A bland face looked out at him.

"We have—ah—verified your statements," said the third voice from Weald. "Just one more item. Are you alone in your ship?"

"Of course," said Calhoun, frowning.

"Quite alone?" insisted the voice.

"Obviously!" said Calhoun.

"No other living creature?" insisted the voice again.

"Of—Oh!" said Calhoun annoyedly. He called over his shoulder. "Murgatroyd! Come here!"

Murgatroyd hopped to his lap and gazed interestedly at the screen. The bland face changed remarkably. The voice changed even more.

"Very good!" it said. "Very, very good! Blueskins do not have tormals! You are Med Service! By all means come in. Your coördinates will be ..."

Calhoun wrote them down. He clicked off the communicator again and growled to Murgatroyd;

"So I might have been a blueskin, eh? And you're my passport, because only Med Ships have members of your tribe aboard! What the hell's the matter, Murgatroyd? They act like they think somebody's trying to get down on their planet with a load of plague-germs!"

He grumbled to himself for minutes. The life of a Med Ship man is not exactly a sinecure, at best. It means long periods in empty space in overdrive, which is absolute and deadly tedium. Then two or three days aground, checking official documents and statistics, and asking questions to see how many of the newest medical techniques have reached this planet or that, and the supplying of information about such as have not arrived. Then lifting out to space for long periods of tedium, to repeat the process somewhere else. Med Ships carry only one man because two could not stand the close contact without quarreling with each other. But Med Ships do carry tormals, like Murgatroyd, and a tormal and a man can get along indefinitely, like a man and a dog. It is a highly unequal friendship, but it seems to be satisfactory to both.

Calhoun was very much annoyed with the way the Med Service had been operated in Sector Twelve. He was one of many men at work to correct the results of incompetence in directing Med Service in the twelfth sector. But it is always disheartening to have to labor at making up for somebody else's blundering, when there is so much new work that needs to be done.

The condition shown by the landing-grid suspicions was a case in point. Blueskins were people who inherited a splotchy skin-pigmentation from other people who'd survived a plague. Weald plainly maintained a one-planet quarantine against them. But a quarantine is normally an emergency measure. The Med Service should have taken over, wiped out the need for a quarantine, and then lifted it. It hadn't been done.

Calhoun fumed to himself.

The world of Weald Three grew brighter and brighter and became a disk. The disk had ice-caps and a reasonable proportion of land and water surface. The Med Ship decelerated, and voices notified observation from the surface, and the little craft came to a stop some five planetary diameters out from solidity. The landing-field force-field locked on to it, and its descent began.

The business of landing was all very familiar, from the blue rim which appeared at the limb of the planet from one diameter out, to the singular flowing-apart of the surface features as the ship sank still lower. There was the circular landing-grid, rearing skyward for nearly a mile. It could let down interstellar liners from emptiness and lift them out to emptiness again, with great convenience and economy for everyone.

It landed the Med Ship in its center, and there were officials to greet Calhoun, and he knew in advance the routine part of his visit. There would be an interview with the planet's chief executive, by whatever title he was called. There would be a banquet. Murgatroyd would be petted by everybody. There would be painful efforts to impress Calhoun with the splendid conduct of public health matters on Weald. He would be told much scandal. He might find one man, somewhere, who passionately labored to advance the welfare of his fellow humans by finding out how to keep them well, or failing that how to make them well when they got sick. And in two days, or three, Calhoun would be escorted back to the landing-grid, and lifted out to space, and he'd spend long empty days in overdrive and land somewhere else to do the whole thing all over again.

It all happened exactly as he expected, with one exception. Every human being he met on Weald wanted to talk about blueskins. Blueskins and the idea of blueskins obsessed everyone. Calhoun listened without asking questions until he had the picture of what blueskins meant to the people who talked of them. Then he knew there would be no use asking questions at random. Nobody mentioned ever having seen a