"He's beyond killing anyone," answered McGrath. "But just the same, we've got to get out of here."

Her eyes flared with new terror.

"Yes! John De Albor! Ballville was afraid of him. That's why he locked me in here. He said he'd sent for you. I was afraid for you——"

"Ali!" McGrath called. "Come in here. We're getting out of here now, and we'd better take some water and food with us. We may have to hide in the swamps for——"

Abruptly Constance shrieked, tore herself from her lover's arms. And McGrath, frozen by the sudden, awful fear in her wide eyes, felt the dull jolting impact of a savage blow at the base of his skull. Consciousness did not leave him, but a strange paralysis gripped him. He dropped like an empty sack on the stone floor and lay there like a dead man, helplessly staring up at the scene which tinged his brain with madness—Constance struggling frenziedly in the grasp of the man he had known as Ali ibn Suleyman, now terribly transformed.

The man had thrown off his turban and glasses. And in the murky whites of his eyes, McGrath read the truth with its grisly implications—the man was not an Arab. He was a negroid mixed breed. Yet some of his blood must have been Arab, for there was a slightly Semitic cast to his countenance, and this cast, together with his oriental garb and his perfect acting of his part, had made him seem genuine. But now all this was discarded and the negroid strain was uppermost; even his voice, which had enunciated the sonorous Arabic, was now the throaty gutturals of the negro.

"You've killed him!" the girl sobbed hysterically, striving vainly to break away from the cruel fingers that prisoned her white wrists.

"He's not dead yet," laughed the octoroon. "The fool quaffed drugged brandy—a drug found only in the Zambebwei jungles. It lies inactive in the system until made effective by a sharp blow on a nerve center."

"Please do something for him!" she begged.

The fellow laughed brutally.