that the dead man was assumed to have
occupied at the moment of the murder, while the plate was exposed, and
then, before I moved, Thorndyke marked the position of my feet with a
blackboard chalk. He next set up the tripod over the chalk marks, and
took two photographs from that position, and finally photographed the
body itself.

The photographic operations being concluded, he next proceeded, with
remarkable skill and rapidity, to lay out on the sketch-block a
ground-plan of the room, showing the exact position of the various
objects, on a scale of a quarter of an inch to the foot--a process that
the inspector was inclined to view with some impatience.

"You don't spare trouble, Doctor," he remarked; "nor time either," he
added, with a significant glance at his watch.

"No," answered Thorndyke, as he detached the finished sketch from the
block; "I try to collect all the facts that may bear on a case. They may
prove worthless, or they may turn out of vital importance; one never
knows beforehand, so I collect them all. But here, I think, is Dr.
Egerton."

The police-surgeon greeted Thorndyke with respectful cordiality, and we
proceeded at once to the examination of the body. Drawing out the
thermometer, my colleague noted the reading, and passed the instrument
to Dr. Egerton.

"Dead about ten hours," remarked the latter, after a glance at it. "This
was a very determined and mysterious murder."

"Very," said Thorndyke. "Feel that dagger, Jervis."

I touched the hilt, and felt the characteristic grating of bone.

"It is through the edge of a rib!" I exclaimed.

"Yes; it must have been used with extraordinary force. And you notice
that the clothing is screwed up slightly, as if the blade had been
rotated as it was driven in. That is a very peculiar feature, especially
when taken together with the violence of the blow."

"It is singular, certainly," said Dr. Egerton, "though I don't know that
it helps us much. Shall we withdraw the dagger before moving the body?"

"Certainly," replied Thorndyke, "or the movement may produce fresh
injuries. But wait." He took a piece of string from his pocket, and,
having drawn the dagger out a couple of inches, stretched the string in
a line parallel to the flat of the blade. Then, giving me the ends to
hold, he drew the weapon out completely. As the blade emerged, the twist
in the clothing disappeared. "Observe," said he, "that the string gives
the direction of the wound, and