fact that not a drawer had been opened or a lock forced, while the money
in his pocket was still intact. The doctors had certified that the wound
could not have been self-inflicted, while there was plenty of evidence
to show that there had not been a struggle. From the fact that the
front-door was locked, and that the key was in the murdered man's
pocket, it was certain that the assassin must have left the house by the
back. There was one question, however, so trivial in itself that one
might have been excused for not taking note of it, that attracted my
attention. As I have said, the old man had been stabbed from behind, and
when he was discovered by the police next day, his overturned chair was
lying beside him. This, to my mind, showed that he had been seated with
his back to the door when the crime had been perpetrated. When I had
examined everything else, I turned my attention to the chair. I did not
expect it to tell me anything, yet it was from it that I obtained the
clue that was ultimately to lead to the solution of the whole mystery.
The chair was a cheap one, made of white wood, and had the usual smooth
strip of wood at the top. On the back of this piece of wood, a quarter
of an inch or so from the bottom, on the left-hand side, was a faint
smear of blood. The presence of the blood set me thinking. When found,
the chair had been exactly eighteen inches from the body. The mere fact
that the man had been stabbed from behind and to the heart, precluded
any possibility of his having jumped up and caught at the back of the
chair afterwards. Placing my left hand upon the back, I clasped my
fingers under the piece of wood above-mentioned, to discover that a
portion of the second finger fell exactly upon the stain.

"Now I think I understand the situation," I said to myself. "The old man
was seated at the table, about to commence his meal, when the murderer
entered very quietly by the door behind him. He rested his left hand
upon the chair to steady himself while he aimed the fatal blow with