'"And now, messieurs et mesdames," said Poirot rapidly, "I will continue with what I was about to say. Understand this, I mean to arrive at the truth. The truth, however ugly in itself, is always curious and beautiful to seeker after it. I am much aged, my powers may not be what they were." Here he clearly expected a contradiction. "In all probability this is the last case I shall ever investigate. But Hercule Poirot does not end with a failure. Messieurs at mesdames, I tell you, I mean to know. And I shall know - in spite of you all."' (from The Murder of Roger Ackroyd, 1926)