Fu-Manchu was watching us, his discolored teeth faintly visible in the dim light, to which my eyes were becoming accustomed.

“Dr. Petrie,” he said, “you shall be my honored guest at my home in China.  You shall assist me to revolutionize chemistry.  Mr. Smith, I fear you know more of my plans than I had deemed it possible for you to have learned, and I am anxious to know if you have a confidant.  Where your memory fails you, and my files and wire jackets prove ineffectual, Inspector Weymouth’s recollections may prove more accurate.”

He turned to the cowering girl—­who shrank away from him in pitiful, abject terror.

“In my hands, Doctor,” he continued, “I hold a needle charged with a rare culture.  It is the link between the bacilli and the fungi.  You have seemed to display an undue interest in the peach and pearl which render my Karamaneh so delightful, In the supple grace of her movements and the sparkle of her eyes.  You can never devote your whole mind to those studies which I have planned for you whilst such distractions exist.  A touch of this keen point, and the laughing Karamaneh becomes the shrieking hag—­the maniacal, mowing—­”

Then, with an ox-like rush, Weymouth was upon him!

Karamaneh, wrought upon past endurance, with a sobbing cry, sank to the deck—­ and lay still.  I managed to writhe into a half-sitting posture, and Smith rolled aside as the detective and the Chinaman crashed down together.

Weymouth had one big hand at the Doctor’s yellow throat; with his left he grasped the Chinaman’s right.  It held the needle.

Now, I could look along the length of the little craft, and, so far as it was possible to make out in the fog, only one other was aboard—­ the half-clad brown man who navigated her—­and who had carried us through the cellars.  The murk had grown denser and now shut us in like a box.  The throb of the motor—­the hissing breath of the two who fought—­ with so much at issue—­these sounds and the wash of the water alone broke the eerie stillness.

By slow degrees, and with a reptilian agility horrible to watch, Fu-Manchu was neutralizing the advantage gained by Weymouth.  His clawish fingers were fast in the big man’s throat; the right hand with its deadly needle was forcing down the left of his opponent.  He had been underneath, but now he was gaining the upper place.  His powers of physical endurance must have been truly marvelous.  His breath was whistling through his nostrils significantly, but Weymouth was palpably tiring.

The latter suddenly changed his tactics.  By a supreme effort, to which he was spurred, I think, by the growing proximity of the needle, he raised Fu-Manchu—­by the throat and arm—­ and pitched him sideways.

The Chinaman’s grip did not relax, and the two wrestlers dropped, a writhing mass, upon the port cushions.  The launch heeled over, and my cry of horror was crushed back into my throat by the bandage.  For, as Fu-Manchu sought to extricate himself, he overbalanced—­ fell back—­and, bearing Weymouth with him—­slid into the river!