and added one of the powders. The mixture, which was at first
of a reddish hue, began, in proportion as the crystals melted, to
brighten in colour, to effervesce audibly, and to throw off small fumes
of vapour. Suddenly and at the same moment, the ebullition ceased and
the compound changed to a dark purple, which faded again more slowly to
a watery green. My visitor, who had watched these metamorphoses with a
keen eye, smiled, set down the glass upon the table, and then turned and
looked upon me with an air of scrutiny.

"And now," said he, "to settle what remains. Will you be wise? will you
be guided? will you suffer me to take this glass in my hand and to go
forth from your house without further parley? or has the greed of
curiosity too much command of you? Think before you answer, for it shall
be done as you decide. As you decide, you shall be left as you were
before, and neither richer nor wiser, unless the sense of service
rendered to a man in mortal distress may be counted as a kind of riches
of the soul. Or, if you shall so prefer to choose, a new province of
knowledge and new avenues to fame and power shall be laid open to you,
here, in this room, upon the instant; and your sight shall be blasted by
a prodigy to stagger the unbelief of Satan."

"Sir," said I, affecting a coolness that I was far from truly
possessing, "you speak enigmas, and you will perhaps not wonder that I
hear you with no very strong impression of belief. But I have gone too
far in the way of inexplicable services to pause before I see the end."

"It is well," replied my visitor. "Lanyon, you remember your vows: what
follows is under the seal of our profession. And now, you who have so
long been bound to the most narrow and material views, you who have
denied the virtue of transcendental medicine, you who have derided your
superiors--behold!"

He put the glass to his lips and drank at one gulp. A cry followed; he
reeled, staggered, clutched at the table and held on, staring with
injected eyes, gasping with open mouth; and as I looked there came, I
thought, a change--he seemed to swell--his face became suddenly black
and the features seemed to melt and alter--and the next moment I had
sprung to my feet and leaped back against the wall, my arm raised to
shield me from that prodigy, my mind submerged in terror.

"O God!" I screamed, and "O God!" again and again; for there before my
eyes--pale and shaken, and half fainting, and groping before