"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 explanation he vouchsafed, but darted off to dress; for he had spent the afternoon pacing the room in his dressing-gown and smoking without intermission.

out and to the corner we hurried, and leaped into the first taxi upon the rank. smith enjoined the man to hasten, and we were off—all in that whirl of feverish activity which characterized my friend's movements in times of important action.

he sat glancing impatiently from the window and twitching at the lobe of his ear.

"i know you will forgive me, old man," he said, "but there is a little problem which i am trying to work out in my mind. did you bring the things i mentioned?"

"yes."

conversation lapsed, until, just as the cab turned into the station, smith said: "should you consider lord southery to have been the first constructive engineer of his time, petrie?"

"undoubtedly," i replied.

"greater than von homber, of berlin?"

"possibly not. but von homber has been dead for three years."

"three years, is it?"

"roughly."

"ah!"

we reached the station in time to secure a non-corridor compartment to ourselves, and to allow smith leisure carefully to inspect the occupants of all the others, from the engine to the guard's van. he was muffled up to the eyes, and he warned me to keep out of sight in the corner of the compartment. in fact, his behavior had me bursting with curiosity. the train having started:

"don't imagine, petrie," said smith "that i am trying to lead you blindfolded in order later to dazzle you with my perspicacity. i am simply afraid that this may be a wild-goose chase. the idea upon which i am acting does not seem to have struck you. i wish it had. the fact would argue in favor of its being sound."

"at present i am hopelessly mystified."

"well, then, i will not bias you towards my view. but just study the situation, and see if you can arrive at the reason for this sudden journey. i shall be distinctly encouraged if you succeed."

but i did not succeed, and since smith obviously was unwilling to enlighten me, i pressed him no more. the train stopped at rugby, where he was engaged with the stationmaster in making some mysterious arrangements. at l—, however, their object became plain, for a high-power car was awaiting us, and into this we hurried and ere the greater number of passengers had reached the platform were being driven off at headlong speed along the moon-bathed roads.

twenty minutes' rapid traveling, and a white mansion leaped into the line of sight, standing out vividly against its woody backing.

"stradwick hall," said smith. "the home of lord southery. we are first—but dr. fu-manchu was on the train."

then the truth dawned upon the gloom of my perplexity.