do we know of Ferrara's activities? His record is
damnable. To our certain knowledge his victims are many. If the murder
of his adoptive father, Sir Michael, was actually the first of his
crimes, we know of three other poor souls who beyond any shadow of
doubt were launched into eternity by the Black Arts of this ghastly
villain--"

"We do, Rob," replied Dr. Cairn sternly.

"He has made attempts upon you; he has made attempts upon me. We owe
our survival"--he pointed to a row of books upon a corner shelf--"to
the knowledge which you have accumulated in half a life-time of
research. In the face of science, in the face of modern scepticism, in
the face of our belief in a benign God, this creature, Antony Ferrara,
has proved himself conclusively to be--"

"He is what the benighted ancients called a magician," interrupted Dr.
Cairn quietly. "He is what was known in the Middle Ages as a wizard.
What that means, exactly, few modern thinkers know; but I know, and
one day others will know. Meanwhile his shadow lies upon a certain
house."

Robert Cairn shook his clenched fists in the air. In some men the
gesture had seemed melodramatic; in him it was the expression of a
soul's agony.

"But, sir!" he cried--"are we to wait, inert, helpless? Whatever he
is, he has a human body and there are bullets, there are knives, there
are a hundred drugs in the British Pharmacopoeia!"

"Quite so," answered Dr. Cairn, watching his son closely, and, by his
own collected manner, endeavouring to check the other's growing
excitement. "I am prepared at any personal risk to crush Antony
Ferrara as I would crush a scorpion; but where is he?"

Robert Cairn groaned, dropping into the big red-leathern armchair, and
burying his face in his hands.

"Our position is maddening," continued the elder man. "We know that
Antony Ferrara visits Mr. Saunderson's house; we know that he is
laughing at our vain attempts to trap him. Crowning comedy of all,
Saunderson does not know the truth; he is not the type of man who
could ever understand; in fact we dare not tell him--and we dare not
tell Myra. The result is that those whom we would protect, unwittingly
are working against us, and against themselves."

"That perfume!" burst out Robert Cairn; "that hell's incense which
loads the atmosphere of Saunderson's house! To think that we know what
it means--that we know what it means!"

"Perhaps _I_ know even better than you do, Rob. The occult uses of
perf