“I am quite well, thank you,” she said.

“You are certain?  Let me walk with you until you feel quite sure of yourself.”

She shook her head, flashed a rapid glance at me with her beautiful eyes, and looked away in a sort of sorrowful embarrassment, for which I was entirely at a loss to account.  Suddenly she resumed: 

“I cannot let my name be mentioned in this dreadful matter, but—­I think I have some information—­for the police.  Will you give this to—­ whomever you think proper?”

She handed me a sealed envelope, again met my eyes with one of her dazzling glances, and hurried away.  She had gone no more than ten or twelve yards, and I still was standing bewildered, watching her graceful, retreating figure, when she turned abruptly and came back.

Without looking directly at me, but alternately glancing towards a distant corner of the square and towards the house of Major-General Platt-Houston, she made the following extraordinary request: 

“If you would do me a very great service, for which I always would be grateful,”—­she glanced at me with passionate intentness—­“when you have given my message to the proper person, leave him and do not go near him any more to-night!”

Before I could find words to reply she gathered up her cloak and ran.  Before I could determine whether or not to follow her (for her words had aroused anew all my worst suspicions) she had disappeared!  I heard the whir of a restarted motor at no great distance, and, in the instant that Nayland Smith came running down the steps, I knew that I had nodded at my post.

“Smith!” I cried as he joined me, “tell me what we must do!” And rapidly I acquainted him with the incident.

My friend looked very grave; then a grim smile crept round his lips.

“She was a big card to play,” he said; “but he did not know that I held one to beat it.”

“What!  You know this girl!  Who is she?”

“She is one of the finest weapons in the enemy’s armory, Petrie.  But a woman is a two-edged sword, and treacherous.  To our great good fortune, she has formed a sudden predilection, characteristically Oriental, for yourself.  Oh, you may scoff, but it is evident.  She was employed to get this letter placed in my hands.  Give it to me.”

I did so.

“She has succeeded.  Smell.”

He held the envelope under my nose, and, with a sudden sense of nausea, I recognized the strange perfume.

“You know what this presaged in Sir Crichton’s case? 
Can you doubt any longer?  She did not want you to share
my fate, Petrie.”

“Smith,” I said unsteadily, “I have followed your lead blindly in this horrible business and have not pressed for an explanation, but I must insist before I go one step farther upon knowing what it all means.”

“Just a few steps farther,” he rejoined; “as far as a cab. 
We are hardly safe here.  Oh, you need not fear shots or knives. 
The man whose servants are watching us now scorns to employ
such clumsy, tell-tale weapons.”