ly they wouldn't. Whatever it
is, it can strike as it likes and without being struck back."

But Dr. Mannering did not answer these questions. He was considering
a little book in his pocket, which he would hand over to the police in
London next morning.

"Poor chap--if he could have begun by taking the problem by the throat,
as he has written here. But, instead, it took him by the throat!"

He took Hardcastle's notebook from his pocket and read again the last
few pages.

"He was dreaming of his theories to the last, when he should surely
have been girt up in every limb to face facts," said Lennox. "He never
realized the horrible danger."

Perusal of the detective's data had revealed an interesting fact. It
was known by his colleagues that he designed a book on the theory and
practice of criminal investigations, and in many of his pocket-books,
subsequently examined, were found memoranda and jottings, doubtless
destined to be worked out at another time. It was clear that he had, for
a few moments, drifted away from the Grey Room in thought when his
death overtook him. Past events, not present problems, were apparently
responsible for the reflections that occupied his mind. He was not
concentrating on the material phenomena actually under his observation
when he died, but following some private meditations provoked by his
experiences.

"Elimination embraces the secret of success," he had written. "Exercise
the full force of your intelligence and spare no pains to eliminate from
every case all matter not bearing directly upon the actual problem. Nine
times out of ten the issue is direct, and once permit side issues to
draw their tracks across it, once admit metaphysical lines of reasoning,
the result will be confusion and a problem increasing in complexity
at every stage. Only in romances, where a plot is invented and then
complicated by deliberate art, shall we find the truth ultimately
permitted to appear in some subordinate incident, or individual,
studiously kept in the background--that is the craft of telling
detective stories. But, in truth, one needs to lay hold of the problem
by the throat at the outset. Deception is too much the province of the
criminal and too little the business of the investigator; and where it
may be possible to creep, like a snake, into a case, unknown for what
you truly are, then your opportunities and chances of success are
enormously increased. It is, however, the exception when one