was deluded by my anxiety to save the man's life, I cannot
say. This at least is certain, I gave the doses too copiously and at too
short intervals.

"The patient recovered--but it was after sustaining some incomprehensibly
deteriorating change in the blood, which destroyed his complexion, and
turned his hair gray. I have since modified the doses; and in dread of
losing the memorandum, I have attached a piece of notched paper to the
bottle, so as to render any future error of judgment impossible. At the
same time, I have facilitated the future administration of the antidote
by adding a label to the bottle, stating the exact quantity of the poison
taken by my servant, as calculated by myself.

"I ought, by the way, to have mentioned in the cipher that experience has
shown me the necessity, if the antidote is to be preserved for any length
of time, of protecting it in blue glass from the influence of light.

"Let me also tell you that I found a vegetable diet of use in perfecting
the effect of the treatment. That mean dread of discovery, which I have
already acknowledged, induced me to avail myself of my wife's help in
nursing the man. When he began to talk of what had happened to him, I
could trust Madame Fontaine to keep the secret. When he was well enough
to get up, the poor harmless creature disappeared. He was probably
terrified at the prospect of entering the laboratory again. In any case,
I have never seen him or heard of him since.

"If you have had patience to read as far as this, you will understand
that I am not sure enough yet of my own discoveries to risk communicating
them to any other person than yourself. Favor me with any chemical
suggestions which may strike you--and then, in case of accidents, destroy
the cipher. For the present farewell."

_Note to Doctor Fontaine's Letter_

"Alexander's Wine" refers to the infamous Roderic Borgia, historically
celebrated as Pope Alexander the Sixth. He was accidentally, and most
deservedly, killed by drinking one of the Borgia poisons, in a bowl of
wine which he had prepared for another person.

The formula for "The Looking-Glass Drops" is supposed to have been found
hidden on removing the wooden lining at the back of a looking-glass,
which had been used by Lucrezia Borgia. Hence the name.

III

The third and last letter which I present is written by me, and was
addressed to Mrs. Wagner during her stay at Frankfort:--

"I exaggerate nothing, my dear aunt,