d letters a single word--

RACHE.

"What do you think of that?" cried the detective, with the air of a
showman exhibiting his show. "This was overlooked because it was in the
darkest corner of the room, and no one thought of looking there. The
murderer has written it with his or her own blood. See this smear where
it has trickled down the wall! That disposes of the idea of suicide
anyhow. Why was that corner chosen to write it on? I will tell you. See
that candle on the mantelpiece. It was lit at the time, and if it was
lit this corner would be the brightest instead of the darkest portion of
the wall."

"And what does it mean now that you _have_ found it?" asked Gregson in a
depreciatory voice.

"Mean? Why, it means that the writer was going to put the female name
Rachel, but was disturbed before he or she had time to finish. You mark
my words, when this case comes to be cleared up you will find that a
woman named Rachel has something to do with it. It's all very well for
you to laugh, Mr. Sherlock Holmes. You may be very smart and clever, but
the old hound is the best, when all is said and done."

"I really beg your pardon!" said my companion, who had ruffled the
little man's temper by bursting into an explosion of laughter. "You
certainly have the credit of being the first of us to find this out,
and, as you say, it bears every mark of having been written by the other
participant in last night's mystery. I have not had time to examine this
room yet, but with your permission I shall do so now."

As he spoke, he whipped a tape measure and a large round magnifying
glass from his pocket. With these two implements he trotted noiselessly
about the room, sometimes stopping, occasionally kneeling, and once
lying flat upon his face. So engrossed was he with his occupation that
he appeared to have forgotten our presence, for he chattered away to
himself under his breath the whole time, keeping up a running fire
of exclamations, groans, whistles, and little cries suggestive of
encouragement and of hope. As I watched him I was irresistibly reminded
of a pure-blooded well-trained foxhound as it dashes backwards and
forwards through the covert, whining in its eagerness, until it comes
across the lost scent. For twenty minutes or more he continued his
researches, measuring with the most exact care the distance between
marks which were entirely invisible to me, and occasionally applying his
tape to t