white mouse!

"Only one capture!" cried my companion, "showing how well-fed the
creatures were. Examine his tail!"

But already I had perceived that to which Smith would draw my attention,
and the mystery of the "astral bells" was a mystery no longer. Bound to
the little creature's tail, close to the root, with fine soft wire
such as is used for making up bouquets, were three tiny silver bells. I
looked across at my companion in speechless surprise.

"Almost childish, is it not?" he said; "yet by means of this simple
device the Gables has been emptied of occupant after occupant. There was
small chance of the trick being detected, for, as I have said, there was
absolutely no aperture from roof to basement by means of which one of
them could have escaped into the building."

"Then..."

"They were admitted into the wall cavities and the rafters, from some
cellar underneath, Petrie, to which, after a brief scamper under the
floors and over the ceilings, they instinctively returned for the
food they were accustomed to receive, and for which, even had it been
possible (which it was not) they had no occasion to forage."

I, too, stood up; for excitement was growing within me. I took up the
piece of silk from the table.

"Where did you find this?" I asked, my eyes upon Smith's keen face.

"In a sort of wine cellar, Petrie," he replied, "under the stair. There
is no cellar proper to the Gables--at least no such cellar appears in
the plans."

"But..."

"But there is one beyond doubt--yes! It must be part of some older
building which occupied the site before the Gables was built. One can
only surmise that it exists, although such a surmise is a fairly safe
one, and the entrance to the subterranean portion of the building is
situated beyond doubt in the wine cellar. Of this we have at least two
evidences:--the finding of the fragment of silk there, and the fact that
in one case at least--as I learned--the light was extinguished in the
library unaccountably. This could only have been done in one way: by
manipulating the main switch, which is also in the wine cellar."

"But Smith!" I cried, "do you mean that Fu-Manchu..."

Nayland Smith turned in his promenade of the floor, and stared into my
eyes.

"I mean that Dr. Fu-Manchu has had a hiding-place under the Gables for
an indefinite period!" he replied. "I always suspected that a man of his
genius would have a second retreat prepared for him, anticipating the
event o