Weymouth was palpably amazed, but Smith’s tone was imperative.  The Inspector departed hastily.

I stared at Smith, not comprehending what prompted this singular course.

“Now that you can think clearly, Mr. West,” he said, “of what does your experience remind you?  The errors of perception regarding time; the idea of seeing A sound; the illusion that the room alternately increased and diminished in size; your fit of laughter, and the recollection of the name Bayard Taylor.  Since evidently you are familiar with that author’s work—­ `The Land of the Saracen,’ is it not?—­these symptoms of the attack should be familiar, I think.”

Norris West pressed his hands to his evidently aching head.

“Bayard Taylor’s book,” he said dully.  “Yes! . . .  I know of what my brain sought to remind me—­Taylor’s account of his experience under hashish.  Mr. Smith, someone doped me with hashish!”

Smith nodded grimly.

“Cannabis indica,” I said—­“Indian hemp.  That is what you were drugged with.  I have no doubt that now you experience a feeling of nausea and intense thirst, with aching in the muscles, particularly the deltoid.  I think you must have taken at least fifteen grains.”

Smith stopped his perambulations immediately in front of West, looking into his dulled eyes.

“Someone visited your chambers last night,” he said slowly, “and for your chloral tabloids substituted some containing hashish, or perhaps not pure hashish.  Fu-Manchu is a profound chemist.”

Norris West started.

“Someone substituted—­” he began.

“Exactly,” said Smith, looking at him keenly; “someone who was here yesterday.  Have you any idea whom it could have been?”

West hesitated.  “I had a visitor in the afternoon,” he said, seemingly speaking the words unwillingly, “but—­”

“A lady?” jerked Smith.  “I suggest that it was a lady.”

West nodded.

“You’re quite right,” he admitted.  “I don’t know how you arrived at the conclusion, but a lady whose acquaintance I made recently—­ a foreign lady.”

“Karamaneh!” snapped Smith.

“I don’t know what you mean in the least, but she came here—­ knowing this to be my present address—­to ask me to protect her from a mysterious man who had followed her right from Charing Cross.  She said he was down in the lobby, and naturally, I asked her to wait here whilst I went and sent him about his business.”

He laughed shortly.

“I am over-old,” he said, “to be guyed by a woman.  You spoke just now of someone called Fu-Manchu.  Is that the crook I’m indebted to for the loss of my plans?  I’ve had attempts made by agents of two European governments, but a Chinaman is a novelty.”

“This Chinaman,” Smith assured him, “is the greatest novelty of his age.  You recognize your symptoms now from Bayard Taylor’s account?”