"Arrested whom?" he asked, with a sharp look I didn't understand.

"My sister."

"Who is that?" This with a smile of indescribable meaning.

"You knew well enough when I was here this afternoon."

"On the contrary, I knew no more than I know now. I don't even know that you have a sister. Have you?"

Either the man was a lunatic, or he knew everything. Here was obviously the reason of the altered reception. But I would not betray myself by a single word or gesture.

"I am speaking of my sister, Olga Petrovitch, whom you rescued from the hands of Major Devinsky. Now, do you know what I mean?"

"No," he answered stolidly.

"Well, do you know whom I mean?"

"I know of Olga Petrovitch."