All the intense hatred that she had felt for that other woman in the days that she had vainly striven to equal her in beauty and win back her husband’s love broke forth.  She was wonderful, magnificent, in her fury.  She was passion personified; she was fate, retribution.

Collins looked at his wife, and even he felt the spell.  It was not crime that she had done; it was elemental justice.

For a moment she stood, silent, facing Kennedy.  Then the colour slowly faded from her cheeks.  She reeled.

Colling caught her and imprinted a kiss, the kiss that for years she had longed and striven for again.  She looked rather than spoke forgiveness as he held her and showered them on her.

“Before Heaven,” I heard him whisper into her ear, “with all my power as a lawyer I will free you from this.”

Gently Dr. Leslie pushed him aside and felt her pulse as she dropped limply into the only easy chair in the laboratory.

“O’Connor,” he said at length, “all the evidence that we really have hangs on an invisible thread of quartz a mile away.  If Professor Kennedy agrees, let us forget what has happened here to-night.  I will direct my jury to bring in a verdict of suicide.  Collins, take good care of her.”  He leaned over and whispered so she could not hear.  “I wouldn’t promise her six weeks otherwise.”

I could not help feeling deeply moved as the newly reunited Collinses left the laboratory together.  Even the bluff deputy, O’Connor, was touched by it and under the circumstances did what seemed to him his higher duty with a tact of which I had believed him scarcely capable.  Whatever the ethics of the case, he left it entirely to Dr. Leslie’s coroner’s jury to determine.

Burke Collins was already making hasty preparations for the care of his wife so that she might have the best medical attention to prolong her life for the few weeks or months before nature exacted the penalty which was denied the law.

“That’s a marvellous piece of apparatus,” I remarked, standing over the connections with the string galvanometer, after all had gone.  “Just suppose the case had fallen into the hands of some of these old-fashioned detectives—­”

“I hate post-mortems—­on my own cases,” interrupted Kennedy brusquely.  “To-morrow will be time enough to clear up this mess.  Meanwhile, let us get this thing out of our minds.”

He clapped his hat on his head decisively and deliberately walked out of the laboratory, starting off at a brisk pace in the moonlight across the campus to the avenue where now the only sound was the noisy rattle of an occasional trolley car.

How long we walked I do not know.  But I do know that for genuine relaxation after a long period of keen mental stress, there is nothing like physical exercise.  We turned into our apartment, roused the sleepy hall-boy, and rode up.