He smiled gently. “It is of the first importance,” he said, “not to allow your judgment to be biased by personal qualities. A client is to me a mere unit, — a factor in a problem. The emotional qualities are antagonistic to clear reasoning. I assure you that the most winning woman I ever knew was hanged for poisoning three little children for their insurance-money, and the most repellant man of my acquaintance is a philanthropist who has spent nearly a quarter of a million upon the London poor.

No, no: I never guess. It is a shocking habit, — destructive to the logical faculty.

Detection is, or ought to be, an exact science, and should be treated in the same cold and unemotional manner. You have attempted to tinge it with romanticism, which produces much the same effect as if you worked a love-story or an elopement into the fifth proposition of Euclid.