“Perhaps we are the criminals,” he replied, laughing.  I shivered slightly at this audacity.  He laughed as he spoke, but there was a hard, metallic, and almost defiant tone in his voice which exasperated me.

“Perhaps we are,” I answered, quietly.  He looked full at me; but I was prepared, and my face told nothing.  I added, as in explanation, “The crime being apparently contagious, we may have brought the infection from Nuremberg.”

“Do you believe in that hypothesis of imitation?”

“I don’t know what to believe.  Do you believe in there being only one murderer?  It seems such a preposterous idea.  We must suppose him, at any rate, to be a maniac.”

“Not necessarily.  Indeed there seems to have been too much artful contrivance in both affairs, not only in the selection of the victims, but in the execution of the schemes.  Cunning as maniacs often are they are still maniacs, and betray themselves.”

“If not a maniac,” said I, hoping to pique him, “he must be a man of stupendous and pitiable vanity,—­perhaps one of your constant-minded friends, whom you refuse to call bloodthirsty.”

“Constant-minded, perhaps; but why pitiably vain?”

“Why?  Because only a diseased atrocity of imagination, stimulating a nature essentially base and weak in its desire to make itself conspicuous, would or could suggest such things.  The silly youth who ‘fired the Ephesian dome,’ the vain idiot who set fire to York Minster, the miserable Frenchmen who have committed murder and suicide with a view of making their exit striking from a world in which their appearance had been contemptible, would all sink into insignificance beside the towering infamy of baseness which—­for the mere love of producing an effect on the minds of men, and thus drawing their attention upon him, which otherwise would never have marked him at all—­could scheme and execute crimes so horrible and inexcusable.  In common charity to human nature, let us suppose the wretch is mad; because otherwise his miserable vanity would be too loathsome.”  I spoke with warmth and bitterness, which increased as I perceived him wincing under the degradation of my contempt.

“If his motive were vanity,” he said, “no doubt it would be horrible; but may it not have been revenge?”

“Revenge!” I exclaimed; “what! on innocent women?”

“You assume their innocence.”

“Good God! do you know anything to the contrary?”

“Not I. But as we are conjecturing, I may as well conjecture it to have been the desire to produce a startling effect.”

“How do you justify your conjecture?”

“Simply enough.  We have to suppose a motive; let us say it was revenge, and see whether that will furnish a clue.”

“But it can’t.  The two victims were wholly unconnected with each other by any intermediate acquaintances, consequently there can have been no common wrong or common enmity in existence to furnish food for vengeance.”