“I am not trying to mystify you,” he assured me.  “But the truth is so hard to believe sometimes that in the present case I hesitate to divulge it.  Did you ever meet Tcheriapin?”

This abrupt change of topic somewhat startled me, but nevertheless: 

“I once heard him play,” I replied.  “Why do you ask the question?”

“For this reason:  Tcheriapin possessed the only other example of this art which so far as I am aware ever left the laboratory of the inventor.  He occasionally wore it in his buttonhole.”

“It is then a manufactured product of some sort?”

“As I have said, in a sense it is; but”—­he drew the tiny exquisite ornament from his pocket again and held it up before me—­“it is a natural bloom.”

“What!”

“It is a natural bloom,” replied my acquaintance, fixing his penetrating gaze upon me.  “By a perfectly simple process invented by the cleverest chemist of his age it had been reduced to this gem-like state while retaining unimpaired every one of its natural beauties, every shade of its natural colour.  You are incredulous?”

“On the contrary,” I replied, “having examined it through a magnifying glass I had already assured myself that no human hand had fashioned it.  You arouse my curiosity intensely.  Such a process, with its endless possibilities, should be worth a fortune to the inventor.”

The stranger nodded grimly and again concealed the rose in his pocket.

“You are right,” he said; “and the secret died with the man who discovered it—­in the great explosion at the Vortex Works in 1917.  You recall it?  The T.N.T. factory?  It shook all London, and fragments were cast into three counties.”

“I recall it perfectly well.”

“You remember also the death of Dr. Kreener, the chief chemist?  He died in an endeavour to save some of the workpeople.”

“I remember.”

“He was the inventor of the process, but it was never put upon the market.  He was a singular man, sir; as was once said of him—­’A Don Juan of science.’  Dame Nature gave him her heart unwooed.  He trifled with science as some men trifle with love, tossing aside with a smile discoveries which would have made another famous.  This”—­tapping his breast pocket—­“was one of them.”

“You astound me.  Do I understand you to mean that Dr. Kreener had invented a process for reducing any form of plant life to this condition?”

“Almost any form,” was the guarded reply.  “And some forms of animal life.”

“What!”

“If you like”—­the stranger leaned forward and grasped my arm—­“I will tell you the story of Dr. Kreener’s last experiment.”

I was now intensely interested.  I had not forgotten the heroic death of the man concerning whose work this chance acquaintance of mine seemed to know so much.  And in the cadaverous face of the stranger as he sat there regarding me fixedly there was a promise and an allurement.  I stood on the verge of strange things; so that, looking into the deep-set eyes, once again I felt the cloak being drawn about me, and I resigned myself willingly to the illusion.