"But they oughtn't to look like us!" Joe Buckner continued.
"There are chemical differences," Susan Sidwell said. "Once, in the laboratory, we analyzed their blood. The color was different for one thing. They also have a much different metabolism."
"But suppose one of them escaped from the museum and got into our part of the world. How would we know he wasn't one of us, if he put on our clothes?" Joe Buckner sounded outraged.
"That is one purpose our bracelets serve," the instructor answered. "A very good question, Joe. As you know, each of us receives a bracelet at birth, which is slipped over the hand and onto the wrist. Made of plasticum, which cannot be cut by any method, the bracelet has the unique property of expanding in size as the wearer grows. It cannot be removed except by cutting off the arm of the wearer." He laughed as if he had made a good joke. "But I am sure no one would ever think of doing that. The bracelet carries the serial number assigned to each of us."
He held up his arm, exhibiting the gleaming circle of plasticum on his wrist. To him—to all of them—it was a badge of honor, a mark that proved one belonged to a superior race. "If one of the natives escaped, the absence of a bracelet would disclose his identity at once. We would take measures to have him eliminated."
"I see," Joe Buckner said. He sounded mollified. "How would we eliminate him?"
"I believe it is customary to use a Thor gun in such cases—a large caliber which will disintegrate him instantly. The model I have will only blast a hole a few inches in diameter."
"I'm going to be a Thorgunman," Joe Buckner said with sudden enthusiasm.
"Good!" the instructor said. "That is a very fine calling. If I had my life to live over again—" He sighed for lost opportunities.
At the announcement of his ambition, Joe Buckner rose higher in the opinion of the class.