something new. Then try again with a fresh one. You remember what I told you of my methods when I began this branch of practice and had plenty of time on my hands?"
"I am not sure that I do."
"Well, I used to occupy my leisure in constructing imaginary cases, mostly criminal, for the purpose of study and for the acquirement of experience. For instance, I would devise an ingenious fraud and would plan it in detail, taking every precaution that I could think of against failure or detection, considering, and elaborately providing for, every imaginable contingency. For the time being, my entire attention was concentrated on it, making it as perfect and secure and undetectable as I could with the knowledge and ingenuity at my command. I behaved exactly as if I were proposing actually to carry it out, and my life or liberty depended on its success—excepting that I made full notes of every detail of the scheme. Then when my plans were as complete as I could make them, and I could think of no way in which to improve them, I changed sides and considered the case from the standpoint of detection. I analysed the case, I picked out its inherent and unavoidable weaknesses, and, especially, I noted the respects in which a fraudulent proceeding of a particular kind differed from the bona fide proceeding that it simulated. The exercise was invaluable to me. I acquired as much experience from those imaginary cases as I should from real ones, and in addition, I learned
