"If she died? Exactly."
Robert Cairn began to stride up and down the room, clenching and unclenching his fists. He was a shadow of his former self, but now his cheeks were flushed and his eyes feverishly bright.
"Before Heaven!" he cried suddenly, "the situation is becoming unbearable. A thing more deadly than the Plague is abroad here in London. Apart from the personal aspect of the matter—of which I dare not think!—what 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 Pharmacopœia!"
"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.