ed to me by Jack."

He repeated Jack's narrative of the opening of the Pink-Room cupboard,
and the administration of the antidote to Mrs. Wagner.

"You will understand," he went on, "that I was too well aware of the
marked difference between Mr. Keller's illness and Mrs. Wagner's illness
to suppose for a moment that the same poison had been given to both of
them. I was, therefore, far from sharing Jack's blind confidence in the
efficacy of the blue-glass bottle, in the case of his mistress. But I
tell you, honestly, my mind was disturbed about it. Towards night, my
thoughts were again directed to the subject, under mysterious
circumstances. Mr. Keller and I accompanied the hearse to the Deadhouse.
On our way through the streets, I was followed and stopped by Madame
Fontaine. She had something to give me. Here it is."

He laid on the table a sheet of thick paper, closely covered with writing
in cipher.

V

"Whose writing is this?" I asked.

"The writing of Madame Fontaine's late husband."

"And she put it into your hands!"

"Yes--and asked me to interpret the cipher for her."

"It's simply incomprehensible."

"Not in the least. She knew the use to which Jack had put her antidote,
and (in her ignorance of chemistry) she was eager to be prepared for any
consequences which might follow. Can you guess on what chance I
calculated, when I consented to interpret the cipher?"

"On the chance that it might tell you what poison she had given to Mrs.
Wagner?"

"Well guessed, Mr. Glenney!"

"And you have actually discovered the meaning of these hieroglyphics?"

He laid a second sheet of paper on the table.

"There is but one cipher that defies interpretation," he said. "If you
and your correspondent privately arrange to consult the same edition of
the same book, and if your cipher, or his, refers to a given page and to
certain lines on that page, no ingenuity can discover you, unaided by a
previous discovery of the book. All other ciphers, so far as I know, are
at the mercy of skill and patience. In this case I began (to save time
and trouble) by trying the rule for interpreting the most simple, and
most elementary, of all ciphers--that is to say, the use of the ordinary
language of correspondence, concealed under arbitrary signs. The right
way to read these signs can be described in two words. On examination of
the cipher, you will find that some signs will be more often repeated
than others. Count the separate