After five minutes of inspection he grunted and hauled out his antibiotic stores. He added infinitesimal traces of cillin to the culture-media. In the microscope, he watched the active microscopic creatures die. He checked with the other samples. He went out to the listless, enfeebled animal. He made a wry guess at its body-weight. He used the injector. He went back to the Med Ship. He called on the spacephone. "I think," he said politely, "that your beast will be all right in thirty hours or so. Now, how about telling me the name of this sun?" The voice said sharply: "_There's a matter of weapons, too! Wait till we see how the cow does! Sunset will come in an hour. When day comes again, if the cow is better--we'll see!_" There was a click. The spacephone cut off. * * * * * Calhoun pulled out the log-mike. There was already an audio record of all ship-operations and communications. Now he added comments--a description of the ribbon in the sky, the appearance of the planet, and such conclusions as he'd come to. He ended: "... The samples from the cow were full of a single coccus, which seemed to have no resistance to standard antibiotics. I pumped the beast full of cillin and called it a day. I'm concerned, though, because of the clear signs of an isolation syndrome here. They're idiotically suspicious of me and won't even promise a bargain, as if I could somehow overreach them because I'm a stranger. They've sentries out--they said somebody sneaked past them--against what I imagine must be Two City and Three City. I've an impression that the sentries are to enforce a quarantine rather than to put up a fight. It is probable that the other communities practice the same tactics--plus biological cold war if somebody did bring a sick cow here to infect and destroy the local herd. These people may have a landing grid, but they've an isolation syndrome and I'm afraid there's a classic Crusoe health problem in being. If that's so, it's going to be nasty!" He cut off the log. The classic Crusoe problem would be extremely awkward if he'd run into it. There was a legend about an individual back on old Earth who'd been left isolated on an island by shipwreck for half a lifetime. His name was given to the public-health difficulties which occurred when accidental isolations occurred during the chaotic first centuries of galactic migration. There was one shipwreck to which the name was first applied. The ship was missing, and the descendants of the crew and passengers were not contacted until three generations had passed. Larger-scale and worse cases occurred later, when colonies were established by entrepreneurs who grew rich in the establishment of the new settlements, and had no interest in maintaining them. Such events could hardly happen now, of course, but even a Crusoe condition was still possible in theory. It might exist here. Calhoun hoped not.