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 coordinates will be ..._" Calhoun wrote them down. He clicked off the communicator again and growled to Murgatroyd;