“Because the truth is very unbelievable,” said Elizabeth.

David lifted his head and looked at her.

“Oh, you’ll not lie,” he said.

“Thank you,” said Elizabeth. After a moment’s pause, she went on.

“Will you sit down, David? I don’t think I can speak if you walk up and down like that. It’s not very easy to speak.”

He sat down in a big chair, that stood with its back to the window.

“David,” she said, “when we were in Switzerland, you asked me how I had put you to sleep. You asked me if I had hypnotised you. I said, No. I want to know if you believed me?”

“I don’t know what I believed,” said David wearily. The question appeared to him to be entirely irrelevant and unimportant.

“When you hypnotise a person, you are producing an illusion,” said Elizabeth. “The effect of what I did was to destroy one. But whatever I did, when you asked me to stop doing it, I stopped. You do believe that?”

“Yes—I believe that.”