“Forgive me, mademoiselle, for my brusquerie.  It is true I forgot myself for a moment.  But you were in danger, and——­”

“In danger!” I exclaimed incredulously.

“Yes, mademoiselle.  This,” and he held up the Venetian decanter to the light, “is not water simply.  If you will observe it now with the sunshine beating full against it, I think you will perceive peculiarities in it that will assure you of my veracity.”

I looked as he bade me, and saw, to my surprise, that the fluid was never actually still for a second.  A sort of internal bubbling seemed to work in its centre, and curious specks and lines of crimson and gold flashed through it from time to time.

“What is it?” I asked; adding with a half-smile, “Are you the possessor of a specimen of the far-famed Aqua Tofana?”

Cellini placed the decanter carefully on a shelf, and I noticed that he chose a particular spot for it, where the rays of the sun could fall perpendicularly upon the vessel containing it.  Then turning to me, he replied: 

“Aqua Tofana, mademoiselle, is a deadly poison, known to the ancients and also to many learned chemists of our day.  It is a clear and colourless liquid, but it is absolutely still—­as still as a stagnant pool.  What I have just shown you is not poison, but quite the reverse.  I will prove this to you at once.”  And taking a tiny liqueur glass from a side table, he filled it with the strange fluid and drank it off, carefully replacing the stopper in the decanter.

“But, Signor Cellini,” I urged, “if it is so harmless, why did you forbid my tasting it?  Why did you say there was danger for me when I was about to drink it?”

“Because, mademoiselle, for you it would be dangerous.  Your health is weak, your nerves unstrung.  That elixir is a powerful vivifying tonic, acting with great rapidity on the entire system, and rushing through the veins with the swiftness of electricity.  I am accustomed to it; it is my daily medicine.  But I was brought to it by slow, and almost imperceptible degrees.  A single teaspoonful of that fluid, mademoiselle, administered to anyone not prepared to receive it, would be instant death, though its actual use is to vivify and strengthen human life.  You understand now why I said you were in danger?”

“I understand,” I replied, though in sober truth I was mystified and puzzled.

“And you forgive my seeming rudeness?”

“Oh, certainly!  But you have aroused my curiosity.  I should like to know more about this strange medicine of yours.”

“You shall know more if you wish,” said Cellini, his usual equable humour and good spirits now quite restored.  “You shall know everything; but not to-day.  We have too little time.  I have not yet commenced your picture.  And I forgot—­you were thirsty, and I was, as you said, inhospitable.  You must permit me to repair my fault.”

And with a courteous salute he left the room, to return almost immediately with a tumbler full of some fragrant, golden-coloured liquid, in which lumps of ice glittered refreshingly.  A few loose rose-leaves were scattered on the top of this dainty-looking beverage.