"WE must arrange for the house to be raided without delay," said Smith. "This time we are sure of our ally—"  
"But we must keep our promise to her," I interrupted.
 
"You can look after that, Petrie," my friend said. "I will devote the whole of my attention to Dr. Fu-Manchu!" he added grimly.
 
Up and down the room he paced, gripping the blackened briar between his teeth, so that the muscles stood out squarely upon his lean jaws. The bronze which spoke of the Burmese sun enhanced the brightness of his gray eyes.
 
"What have I all along maintained?" he jerked, looking back at me across his shoulder—"that, although Karamaneh was one of the strongest weapons in the Doctor's armory, she was one which some day would be turned against him. That day has dawned."
 
"We must await word from her."
 
"Quite so."
 
He knocked out his pipe on the grate. Then:
 
"Have you any idea of the nature of the fluid in the phial?"
 
"Not the slightest. And I have none to spare for analytical purposes."
 
Nayland Smith began stuffing mixture into the hot pipe-bowl, and dropping an almost equal quantity on the floor.
 
"I cannot rest, Petrie," he said. "I am itching to get to work. Yet, a false move, and—" He lighted his pipe, and stood staring from the window.
 
"I shall, of course, take a needle-syringe with me," I explained.
 
Smith made no reply.
 
"If I but knew the composition of the drug which produced the semblance of death," I continued, "my fame would long survive my ashes."
 
My friend did not turn. But:
 
"She said it was something he put in the wine?" he jerked.
 
"In the wine, yes."
 
Silence fell. My thoughts reverted to Karamaneh, whom Dr. Fu-Manchu held in bonds stronger than any slave-chains. For, with Aziz, her brother, suspended between life and death, what could she do save obey the mandates of the cunning Chinaman? What perverted genius was his! If that treasury of obscure wisdom which he, perhaps alone of living men, had rifled, could but be thrown open to the sick and suffering, the name of Dr. Fu-Manchu would rank with the golden ones in the history of healing.
 
Nayland Smith suddenly turned, and the expression upon his face amazed me.
 
"Look up the next train to L—!" he rapped.
 
"To L—? What—?"
 
"There's the Bradshaw. We haven't a minute to waste."
 
In his voice was the imperative note I knew so well; in his eyes was the light which told of an urgent need for action—a portentous truth suddenly grasped.
 
"One in half-an-hour—the last."
 
"We must catch it."
 
No further word of ............