ng
a newspaper (I may mention that everything of value in the office was
securely locked up!) I was determined upon a certain course by this
time, and I went slowly upstairs, unlocked the door, and walked into the
darkened office. I turned up the light... the place was empty!"

"Empty!"

"The window was open, and the bird flown! Oh! it was not so simple a
flight--as you would realize if you knew the place. The street, which
the window overlooked, was bounded by a blank wall, on the opposite
side, for thirty or forty yards along; and as we had been having heavy
rains, it was full of glutinous mud. Furthermore, the boy whom I had
left in charge had been sitting in the doorway immediately below the
office window watching for my return ever since his last visit to the
room above..."

"She must have bribed him," I said bitterly--"or corrupted him with her
infernal blandishments."

"I'll swear she did not," rapped Smith decisively. "I know my man, and
I'll swear she did not. There were no marks in the mud of the road to
show that a ladder had been placed there; moreover, nothing of the kind
could have been attempted whilst the boy was sitting in the doorway;
that was evident. In short, she did not descend into the roadway and did
not come out by the door..."

"Was there a gallery outside the window?"

"No; it was impossible to climb to right or left of the window or up on
to the roof. I convinced myself of that."

"But, my dear man!" I cried, "you are eliminating every natural mode of
egress! Nothing remains but flight."

"I am aware, Petrie, that nothing remains but flight; in other words I
have never to this day understood how she quitted the room. I only know
that she did."

"And then?"

"I saw in this incredible escape the cunning hand of Dr. Fu-Manchu--saw
it at once. Peace was ended; and I set to work along certain channels
without delay. In this manner I got on the track at last, and learned,
beyond the possibility of doubt, that the Chinese doctor lived--nay! was
actually on his way to Europe again!"

There followed a short silence. Then:

"I suppose it's a mystery that will be cleared up some day," concluded
Smith; "but to date the riddle remains intact." He glanced at the clock.
"I have an appointment with Weymouth; therefore, leaving you to the task
of solving this problem which thus far has defied my own efforts, I will
get along."

He read a query in my glance.

"Oh! I shall not be late," he a