olution by my learned friend," he
replied with an exasperating smile, and then added: "I don't say that
you and Polton are wrong; only that I don't agree with you. Perhaps you
had better make a note of the properties of this object, and consider it
at your leisure when you are ruminating on the other data referring to
the Blackmore case."

"My ruminations," I said, "always lead me back to the same point."

"But you mustn't let them," he replied. "Shuffle your data about. Invent
hypotheses. Never mind if they seem rather wild. Don't put them aside on
that account. Take the first hypothesis that you can invent and test it
thoroughly with your facts. You will probably have to reject it, but you
will be certain to have learned 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 <i>bona fide</i> 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 a method which is the one that I practise to this
day."

"Do you mean that you still invent imaginary cases as mental exercises?"

"No; I mean that, when I have a problem of any intricacy, I invent a
case which fits the facts and the assu