"So, Mr. Barnes," said the Doctor, opening the conversation, "you have attained your ambition, and are now a full-fledged detective. I have read something of your achievements, and have watched your progress with some interest. I congratulate you upon your success."
"Dr. Medjora," said the detective, with much dignity, "the object of my visit is so serious that I cannot accept flattery. We will proceed to business, if you please."
"As you choose! Let me see! From your card, I judge that you fancy that there is some suspicious circumstance about my late wife's death. You speak of a coincidence which connects hers with that of my first wife. What is it?"
"Both died of diphtheria," said Mr. Barnes, impressively.
"You are entirely mistaken, sir," said the Doctor, with a touch of anger. "My first wife, Mabel, died of morphine, self-administered, and fatal because of other organic disease from which she suffered. She did not die of diphtheria."
"A physician so testified, and signed a death certificate to that effect."
"He did, but he was mistaken. Physicians are mortal as other men are, and as liable to errors of judgment. I repeat, Mabel died of poison."
"Well, we will pass that for a moment. Your last wife died of diphtheria, and she did not contract that disease legitimately."
"No? You interest me. Pray then how did she contract it?"
"By inoculation with the bacillus of diphtheria, Dr. Medjora, and you administered this new form of poison, which an autopsy does not disclose."