e of
justice. Take it! You will deliver it at the Russian Embassy. Now I have
done my duty, and----"

"Stop her!" cried Holmes. He had bounded across the room and had
wrenched a small phial from her hand.

"Too late!" she said, sinking back on the bed. "Too late! I took the
poison before I left my hiding-place. My head swims! I am going! I
charge you, sir, to remember the packet."

"A simple case, and yet in some ways an instructive one," Holmes
remarked, as we travelled back to town. "It hinged from the outset upon
the pince-nez. But for the fortunate chance of the dying man having
seized these I am not sure that we could ever have reached our solution.
It was clear to me from the strength of the glasses that the wearer must
have been very blind and helpless when deprived of them. When you asked
me to believe that she walked along a narrow strip of grass without
once making a false step I remarked, as you may remember, that it was
a noteworthy performance. In my mind I set it down as an impossible
performance, save in the unlikely case that she had a second pair of
glasses. I was forced, therefore, to seriously consider the hypothesis
that she had remained within the house. On perceiving the similarity of
the two corridors it became clear that she might very easily have made
such a mistake, and in that case it was evident that she must have
entered the Professor's room. I was keenly on the alert, therefore,
for whatever would bear out this supposition, and I examined the room
narrowly for anything in the shape of a hiding-place. The carpet seemed
continuous and firmly nailed, so I dismissed the idea of a trap-door.
There might well be a recess behind the books. As you are aware, such
devices are common in old libraries. I observed that books were piled
on the floor at all other points, but that one bookcase was left clear.
This, then, might be the door. I could see no marks to guide me, but the
carpet was of a dun colour, which lends itself very well to examination.
I therefore smoked a great number of those excellent cigarettes, and I
dropped the ash all over the space in front of the suspected bookcase.
It was a simple trick, but exceedingly effective. I then went downstairs
and I ascertained, in your presence, Watson, without your perceiving
the drift of my remarks, that Professor Coram's consumption of food had
increased--as one would expect when he is supplying a second person. We
then ascended to the room ag