“It’s Logan!” cried Inspector Weymouth; and I could tell that he was struggling to free himself of his bonds.  From his voice it was evident that he, too, was recovering from the effects of the narcotic which had been administered to us all.

“Logan!” he cried.  “Logan!  This way—­help!”

But the cry beat back upon us in that enclosed space and seemed to carry no farther than the invisible walls of our prison.

“The door fits well,” came Fu-Manchu’s mocking voice.  “It is fortunate for us all that it is so.  This is my observation window, Dr. Petrie, and you are about to enjoy an unique opportunity of studying fungology.  I have already drawn your attention to the anaesthetic properties of the lycoperdon, or common puff-ball.  You may have recognized the fumes?  The chamber into which you rashly precipitated yourselves was charged with them.  By a process of my own I have greatly enhanced the value of the puff-ball in this respect.  Your friend, Mr. Weymouth, proved the most obstinate subject; but he succumbed in fifteen seconds.”

“Logan!  Help!  Help!  This way, man!”

Something very like fear sounded in Weymouth’s voice now.  Indeed, the situation was so uncanny that it almost seemed unreal.  A group of men had entered the farthermost cellars, led by one who bore an electric pocket-lamp.  The hard, white ray danced from bloated gray fungi to others of nightmare shape, of dazzling, venomous brilliance.  The mocking, lecture-room voice continued: 

“Note the snowy growth upon the roof, Doctor.  Do not be deceived by its size.  It is a giant variety of my own culture and is of the order empusa.  You, in England, are familiar with the death of the common house-fly—­ which is found attached to the window-pane by a coating of white mold.  I have developed the spores of this mold and have produced a giant species.  Observe the interesting effect of the strong light upon my orange and blue amanita fungus!”

Hard beside me I heard Nayland Smith groan, Weymouth had become suddenly silent.  For my own part, I could have shrieked in pure horror.  For I knew what was coming.  I realized in one agonized instant the significance of the dim lantern, of the careful progress through the subterranean fungi grove, of the care with which Fu-Manchu and his servant had avoided touching any of the growths.  I knew, now, that Dr. Fu-Manchu was the greatest fungologist the world had ever known; was a poisoner to whom the Borgias were as children—­and I knew that the detectives blindly were walking into a valley of death.

Then it began—­the unnatural scene—­the saturnalia of murder.

Like so many bombs the brilliantly colored caps of the huge toadstool-like things alluded to by the Chinaman exploded, as the white ray sought them out in the darkness which alone preserved their existence.  A brownish cloud—­I could not determine whether liquid or powdery—­ arose in the cellar.