Now his practical Scotch intelligence brought him back with a
snap to the matter in hand.

"He can keep, anyhow," said he. "You've got us side-tracked with
your interesting anecdotes, Mr. Holmes. What really counts is
your remark that there is some connection between the professor
and the crime. That you get from the warning received through
the man Porlock. Can we for our present practical needs get any
further than that?"

"We may form some conception as to the motives of the crime. It
is, as I gather from your original remarks, an inexplicable, or
at least an unexplained, murder. Now, presuming that the source
of the crime is as we suspect it to be, there might be two
different motives. In the first place, I may tell you that
Moriarty rules with a rod of iron over his people. His
discipline is tremendous. There is only one punishment in his
code. It is death. Now we might suppose that this murdered
man--this Douglas whose approaching fate was known by one of the
arch-criminal's subordinates--had in some way betrayed the chief.
His punishment followed, and would be known to all--if only to
put the fear of death into them."

"Well, that is one suggestion, Mr. Holmes."

"The other is that it has been engineered by Moriarty in the
ordinary course of business. Was there any robbery?"

"I have not heard."