was conspiring, or the grace and kindliness with which she waited upon the
injured man. And yet it would be the blackest treachery to Holmes to draw
back now from the part which he had intrusted to me. I hardened my heart,
and took the smoke-rocket from under my ulster. After all, I thought, we
are not injuring her. We are but preventing her from injuring another.

Holmes had sat upon the couch, and I saw him motion like a man who is in
need of air. A maid rushed across and threw open the window. At the same
instant I saw him raise his hand, and at the signal I tossed my rocket
into the room with a cry of "Fire!" The word was no sooner out of my mouth
than the whole crowd of spectators, well dressed and ill--gentlemen,
hostlers, and servant maids--joined in a general shriek of "Fire!" Thick
clouds of smoke curled through the room, and out at the open window. I
caught a glimpse of rushing figures, and a moment later the voice of
Holmes from within assuring them that it was a false alarm. Slipping
through the shouting crowd, I made my way to the corner of the street, and
in ten minutes was rejoiced to find my friend's arm in mine, and to get
away from the scene of uproar. He walked swiftly and in silence for some
few minutes, until we had turned down one of the quiet streets which led
toward the Edgeware Road.

"You did it very nicely, doctor," he remarked. "Nothing could have been
better. It is all right."

"You have the photograph?"

"I know where it is."

"And how did you find out?"