I was somewhat taken aback, for Harley’s argument was strictly logical, and:
“It is certainly very puzzling,” I admitted.
“Puzzling!” he exclaimed; “it is maddening. This case is like a Syrian village-mound. Stratum lies under stratum, and in each we meet with evidence of more refined activity than in the last. It seems we have yet to go deeper.”
He took out his pipe and began to fill it.
“Tell me about the interview with Madame de Stämer,” he directed.
I took a seat facing him, and he did not once interrupt me throughout my account of Inspector Aylesbury’s examination of Madame.
“Good,” he commented, when I had told how the Inspector was dismissed. “But at least, Knox, he has a working theory, to which he sticks like an express to the main line, whereas I find myself constantly called upon to readjust my perspective. Directly I can enjoy freedom of movement, however, I shall know whether my hypothesis is a house of cards or a serviceable structure.”
“Your hypothesis?” I said. “Then you really have a theory which is entirely different from mine?”
“Not entirely different, Knox, merely not so comprehensive. I have contented myself thus far with a negative theory, if I may so express it.”
“Negative theory?”