"But there is a question in this last case. Madame died of diphtheria, and since you admit that you can produce it by inoculation, what am I to believe?"
"I care not what you believe," said the Doctor, sharply, "so long as you can prove nothing."
"Well, then, since you do not care," said the detective, nettled, "let me tell you that I believe you deliberately planned to kill your last wife. What is more, I do not doubt that a jury would adopt my views."
"In that you are utterly mistaken. Were I considering myself alone, I would permit you to accuse me, feeling perfectly confident that I would be in no danger."
"You are a bold man!"
"Not at all! Where there is no danger, there can be no special bravery. Why, my dear Mr. Barnes, you have no case at all against me. In your own mind you think that there is ample proof, but much of what you know could not be offered to a jury. You are aware of the fact that the diphtheria bacillus was known to me prior to my first wife's death, and so you trace a connection between the two cases. But my lawyer would merely show that the discovery was made ten years after Mabel died, and any further allusion to my first trial would be ruled out. I know enough about law, to know that previous crimes, or accusations of crime, cannot be cited unless they form a part of a system, and as your idea of induced diphtheria could not be substantiated, all of that part of your evidence would be irrelevant."
"That would be a question for the presiding judge to decide."
"If he decide other than as I have stated, we would get a new trial on appeal. The law is specific, and the point is covered by endless precedents. Now then, obliged to confine yourself to positive evidence in the present case, what could you do? You think you could show a motive, but a motive may exist and not be followed by a crime, and your motive is weak besides. Next, you declare that I had the knowledge and the opportunity. I might have both, and still refrain from a murder. But you say that the tube containing the bacillus was missing from my laboratory on that very night, and that my son, Leon, saw me take it. I think that you have formed a rash conclusion on this point, because I doubt that Leon has told you any such thing. However, granting that it is true, and even that the boy would so testify, I am sure that he would admit under cross-examination that it is a common habit for me to take such tubes to my room to make slides for the microscope." The detective recalled that Leon had made this same explanation, and he realized that the Doctor had made a valuable point in his own defence. Dr. Medjora continued: "We would produce the slides which I did actually make, and, being warned by you so early, it would be easy for me to remain in your company until I could send for an expert to examine the slides, so that at the trial he would be able to testify, that from the condition of the balsam he could swear that they had been very recently made. Thus, by admitting all of the damaging parts of your evidence, and then explaining them so that they become consistent with the hypothesis of innocence, we would feel safe. You would still be at the very beginning of your case. It would devolve upon you to show that I not only made the slides, but that I likewise used a part of the contents of that tube to inoculate my wife. You would need to show how such an act were possible. You have no witness who saw me commit the deed which you charge, have you?"
"No," said Mr. Barnes, reluctantly. "But I still think that the circumstantial evidence is sufficient." Mr. Barnes felt sure that this man was guilty, and however skilfully his defence was planned he was reluctant to yield.
"It is sufficient!" said Dr. Medjora, "Not to convict me at a trial by jury, but to raise a doubt of my innocence in the minds of those, whose good will I am determined not to forfeit. Therefore I will not submit to a trial."