Suddenly grasping Karamaneh by the waist, he lifted her and set her aside; then in three bounds he was on to the model’s throne and had torn the Plush curtains bodily from their fastenings.

How it occurred I cannot hope to make dear, for here my recollections merge into a chaos.  I know that Smith seemed to topple forward amid the purple billows of velvet, and his muffled cry came to me: 

“Petrie!  My God, Petrie!” . . .

The pale face of Karamaneh looked up into mine and her hands were clutching me, but the glamour of her personality had lost its hold, for I knew—­heavens, how poignantly it struck home to me!—­that Nayland Smith was gone to his death.  What I hoped to achieve, I know not, but hurling the trembling girl aside, I snatched the Browning pistol from my coat pocket, and with the ray of the lamp directed upon the purple mound of velvet, I leaped forward.

I think I realized that the curtains had masked a collapsible trap, a sheer pit of blackness, an instant before I was precipitated into it, but certainly the knowlege came too late.  With the sound of a soft, shuddering cry in my ears, I fell, dropping lamp and pistol, and clutching at the fallen hangings.  But they offered me no support.  My head seemed to be bursting; I could utter only a hoarse groan, as I fell—­fell—­fell . . .

When my mind began to work again, in returning consciousness, I found it to be laden with reproach.  How often in the past had we blindly hurled ourselves into just such a trap as this?  Should we never learn that where Fu-Manchu was, impetuosity must prove fatal?  On two distinct occasions in the past we had been made the victims of this device, yet even although we had had practically conclusive evidence that this studio was used by Dr. Fu-Manchu, we had relied upon its floor being as secure as that of any other studio, we had failed to sound every foot of it ere trusting our weight to its support. . . .

“There is such a divine simplicity in the English mind that one may lay one’s plans with mathematical precision, and rely upon the Nayland Smiths and Dr. Petries to play their allotted parts.  Excepting two faithful followers, my friends are long since departed.  But here, in these vaults which time has overlooked and which are as secret and as serviceable to-day as they were two hundred years ago, I wait patiently, with my trap set, like the spider for the fly! . . .”

To the sound of that taunting voice, I opened my eyes.  As I did so I strove to spring upright—­only to realize that I was tied fast to a heavy ebony chair inlaid with ivory, and attached by means of two iron brackets to the floor.

“Even children learn from experience,” continued the unforgettable voice, alternately guttural and sibilant, but always as deliberate as though the speaker were choosing with care words which should perfectly clothe his thoughts.  “For ‘a burnt child fears the fire,’ says your English adage.  But Mr. Commissioner Nayland Smith, who enjoys the confidence of the India Office, and who is empowered to control the movements of the Criminal Investigation Department, learns nothing from experience.  He is less than a child, since he has twice rashly precipitated himself into a chamber charged with an anesthetic prepared, by a process of my own, from the lycoperdon or Common Puff-ball.”