to no avail. My duty, I felt, was to leave no
stone unturned until I had discovered whether Gabrielle Engledue had
died from natural causes, or as a result of foul play.

The pale, tragic face of the girl I had encountered in the Duomo
haunted me. Towards the narrow-eyed Doctor Moroni I felt an
instinctive dislike, even though I had no cause to distrust him.

I think it was the strange intuition I experienced at that moment
which caused me to decide to act with discretion and caution, and to
discover all that I could concerning the doctor and his tragic-faced
companion.

With a fixed plan I returned to my hotel, ate my luncheon in the big
_salle a manger_, which was crowded with foreigners wintering in
Florence. Then, after lunch, I complained to the manager of feeling
unwell, and asked him to telephone to Doctor Moroni, in the Via
Cavezzo.

"Ah! a most excellent doctor!" remarked the hotel manager. "He has a
very large practice among the English and Americans. And he is quite
popular. I suppose you know him?"

"No. I have only heard of him, and of his cleverness," I said with
affected carelessness.

Ten minutes later the manager sent me a message by a page that the
doctor would call at three o'clock. So, in my pretended illness, I
went to my room and feigned the symptoms of acute indigestion.

Punctually the doctor arrived, and greeted me in his most professional
manner. I at once explained that an American lady of my acquaintance
had recommended him, whereupon he bowed, smiled, and seating himself
before me inquired my symptoms.

His looks were certainly not an index to his character, for though he
appeared so stern and taciturn yet at heart he was, I saw, a very
humorous, easy-going man, a true Tuscan who showed his white teeth
when he laughed, gesticulated violently, and spoke English with a
refined accent that was particularly charming.

"It is probably the change of diet," he declared at last, after
diagnosing my symptoms. "I see many such cases among foreigners who
are unused to some of our rather indigestible dishes. The latter are
very toothsome, and they eat heartily--with dire results," and he
smiled.

So well indeed did I describe my supposed ailment that before he left
he wrote me out a prescription. Afterwards I made pretence of being a
perfect stranger in Florence. I longed to speak of Oswald De Gex, but
feared to do so because his suspicions might by that become aroused.
If so, then all hop