Then Rosa, with strange deliberation, put her hand to her hair and pulled out the jewelled dagger.

“Sir Cyril,” she said, “you seem fascinated by this little weapon.  Do you recognize it?”

He made no answer, nor moved, but I noticed that his hands were tightly clenched.

“You do recognize it, Sir Cyril?”

At last he nodded.

“Then take it.  The dagger shall be yours.  To-night, within the last minute, I think I have suddenly discovered that, next to myself, you have the best right to it.”

He opened his lips to speak, but made no sound.

“See,” she said.  “It is a real dagger, sharp and pointed.”

Throwing back her cloak with a quick gesture, she was about to prick the skin of her left arm between the top of her long glove and the sleeve of her low-cut dress.  But Sir Cyril, and I also, jumped to stop her.

“Don’t do that,” I said.  “You might hurt yourself.”

She glanced at me, angry for the instant; but her anger dissolved in an icy smile.

“Take it, Sir Cyril, to please me.”

Her intonation was decidedly peculiar.

And Sir Cyril took the dagger.

“Miss Rosa’s carriage,” a commissionaire shouted, and, beckoning to me, the girl moved imperiously down the steps to the courtyard.  There was no longer a smile on her face, which had a musing and withdrawn expression.  Sir Cyril stood stock-still, holding the dagger.  What the surrounding lackeys thought of this singular episode I will not guess.  Indeed, the longer I live, the less I care to meditate upon what lackeys do think.  But that the adventures of their employers provide them with ample food for thought there can be no doubt.

Rosa’s horses drew us swiftly away from the Grand Babylon Hotel, and it seemed that she wished to forget or to ignore the remarkable incident.  For some moments she sat silent, her head slightly bent, her cloak still thrown back, but showing no sign of agitation beyond a slightly hurried heaving of the bosom.

I was discreet enough not to break in upon her reflections by any attempt at conversation, for it seemed to me that what I had just witnessed had been a sudden and terrible crisis, not only in the life of Sir Cyril, but also in that of the girl whose loveliness was dimly revealed to me in the obscurity of the vehicle.

We had got no further than Trafalgar Square when she aroused herself, looked at me, and gave a short laugh.

“I suppose,” she remarked, “that a doctor can’t cure every disease?”

“Scarcely,” I replied.

“Not even a young doctor?” she said with comical gravity.

“Not even a young doctor,” I gravely answered.

Then we both laughed.

“You must excuse my fun,” she said.  “I can’t help it, especially when my mind is disturbed.”

“Why do you ask me?” I inquired.  “Was it just a general observation caused by the seriousness of my countenance, or were you thinking of something in particular?”