e left side, just
visible in the stripe of the pyjama jacket, was the blow which had
caused death--a small orifice like a knife cut, just over the heart.

"It is a very small wound to have killed so strong a man," said Mr.
Cromering. "There is hardly any blood."

Sir Henry examined the wound closely. "The blow was struck with great
force, and penetrated the heart. The weapon used--a small, thin, steel
instrument--and internal bleeding, account for the small external flow."

"What do you mean by a thin, steel instrument?" asked Superintendent
Galloway. "Would an ordinary table-knife answer that description?"

"Certainly. In fact, the nature of the wound strongly suggests that it
was made by a round-headed, flat-bladed weapon, such as an ordinary
table or dinner knife. The thrust was made horizontally,--that is,
across the ribs and between them, instead of perpendicularly, which is
the usual method of stabbing. Apparently the murderer realised that his
knife was too broad for the purpose, and turned it the other way, so as
to make sure of penetrating the ribs and reaching the heart."

"Does not that suggest a rather unusual knowledge of human anatomy on
the murderer's part?" asked Mr. Cromering.

"I do not think so. Anybody can tell how far apart the human ribs are by
feeling them."

"It is easy to see, Sir Henry, that the wound was made by a thin-bladed
knife, but why do you think it was also round-headed?" asked
Superintendent Galloway. "Might it not have been a sharp-pointed one?"

"Or even a dagger?" suggested Mr. Cromering.

"Certainly not a dagger. The ordinary dagger would have made a wider
perforation with a corresponding increase in the blood-flow. My theory of
a round-headed knife is based on the circumstance of a portion of the
deceased's pyjama jacket having been carried into the wound. A
sharp-pointed knife would have made a clean cut through the jacket."

"I see," said Superintendent Galloway, with a sharp nod.

"Therefore, we may assume, in the case before us,"--Sir Henry Durwood
waved a fat white hand in the direction of the corpse as though he were
delivering an anatomical lecture before a class of medical
students--"that the victim was killed with a flat, round knife with a
round edge, held sideways. Furthermore, the position of the wound
reveals that the blow was too much on the left side to pierce the centre
of the heart directly, but was a slanting blow, delivered with such
force that it h