The Ambulance Made Two Trips

He went to the slightly dusty, partly-plastic machine. On its shelf were some parts of metal, and some of transparent plastic, and some grayish, granular substance it was hard to identify. There was an elaborate diagram of something like an electronic circuit inside, but it might have been a molecular diagram from organic chemistry. Brink made an adjustment and pressed firmly on a special part of the machine, which did not yield at all. Then he took a slip of plastic out of a slot in the bottom.

"You can call this a good-luck charm," he said pleasantly, "or a talisman. Actually it's a psionic unit. One like it works very well, for me. Anyhow there's no harm in it. Just one thing. If your eyelids start to twitch, you'll be headed for danger or trouble or something unpleasant. So if they do twitch, stop and be very, very careful. Please!"

He handed the bit of plastic to Fitzgerald, who took i