He grunted. "Jake," I said, "I think I've got that dingus figured." He snuck a glance over at the desk so I knew he knew what I meant, but he was busy pretending that wasn't what he came to talk about.
"I think it's a gun that can read minds like a gypsy," I said. Jake still looked bored, so I took the umbrella handle out of the rolltop and waved it at him. He dove off the chair and started rolling for the door.
"You damn fool," I said, "it won't go off." I was reasonably certain it wouldn't, but I laid it back down by the disk gently anyhow and sat in the chair. I've only got the one chair, on the theory that anybody who isn't bad enough to lie on the table is well enough to stand. Jake edged over and stood like a short-legged bird on a bobwire fence. "It kin whut?" he said.
"It can read minds," I said. "You were going to bash those bones. The gun knew it and trained square on your head. You remember?"
He remembered. "And those Indians," I went on. "You remember them? The left side of the head on each of them was blown off."
I hauled down a roller chart of the human skeleton, first time I'd done that since I don't know when.
"This up here is the brain," I said. "We don't know a hell of a lot about it, but we do know it's like a whole roomful of telegraphers, sending messages to different parts of the body along the nerves. They're like the wires. This left hemisphere—right here—sends to the right side of the body. Don't fret about why, the nerves twist going into the spinal cord.
"Okay. We know, too, that the part of the brain that sends to the arm is right here, in the parietal lobe. Right under the chunk of skull that was shot off on those three Indians."
"Shaw," Jake said, perching on the table. The old billy-goat was beginning to get impressed, even if he didn't have any notion of what I was talking about.