or I saw two couples walking there as I
approached.

Beneath a tree I took cover and waited--waited to establish the
identity of the person whom he had marked down as his next victim.

That night I had gained much knowledge of intense interest, yet it all
served to puzzle me the more.

That Tito Moroni was his accomplice I had established beyond doubt,
and equally that there had been a grave and deep-laid conspiracy
against me. And further, it seemed to be intended that I should again
meet the mysterious pale-faced girl in black, and that the meeting was
meant to be fatal to me.

Fortune had certainly been upon my side that night, otherwise I might
have acted in good faith and fallen into some cleverly-baited trap.
That the doctor of the Via Cavezzo was a dangerous malefactor was
proved by the airy manner in which he had brought to his rich client
that little glass tube which I, of course, had not seen, but which he
had no doubt put into the hands of his wealthy and unscrupulous host.

The more I reflected as I stood beneath the great oleander, the more
puzzled did I become. What was it that De Gex had shown the doctor
beneath the pale light of the moon? It was evidently something which
greatly surprised Moroni, and yet he had made but little comment
concerning it.

But the chief mystery of all was the whereabouts of that poor inert
girl Gabrielle Engledue. I waited, eager for the return of the tall,
well-set-up man in evening clothes, the man who so much in the public
eye was engaged in such a strange career of wickedness and crime.

It seemed incredible that the immensely rich man whose name was so
constantly in the papers as a generous patron of the arts, and a pious
philanthropist, should be implicated in such devil's doings as those
of which I had already proved him to be the author.

The discordant clanging of that convent-bell again aroused me to a
sense of my surroundings. I saw upon the terrace before me several men
strolling, smoking cigarettes, and with them their fair partners
wrapped in rich cloaks and furs. They had come out after supper to
admire the wonderful moonlit scene, for before them rose the
snow-tipped mountains in a long serrated range, the high Apennines
which divide the Adriatic from the Mediterranean.

Suddenly, almost before I was aware of it, a man and a woman passed
close to me. The figure revealed by the cold bright moon was that of
De Gex, who had now put on a light coat, whil