Explanation of the Charts
Chart A shows the fluctuations in the illness of Stella Keene during the year preceding her death in October. Divided into intervals of five days.
Chart B shows the distribution of the arsenical bands in Stella Keene’s hair. The steep sides of the curves, towards the tips of the hairs, show the sudden appearance of the deposit, and the sloping sides, towards the roots of the hairs, represent its more gradual fading. Each of the narrow divisions represents five days’ growth.
Chart C shows the periods during which Barbara was absent from home, each absence being represented by a black column. Divided into intervals of five days.
I gazed at the three charts and was profoundly impressed by the convincing way in which they demonstrated the connection between Barbara’s movements and the results of her diabolical activities. But what impressed me still more was the amazing ingenuity with which Thorndyke had contrived to build up a case of the most deadly precision and completeness out of what seemed, even to my trained intelligence, no more than a few chance facts, apparently quite trivial and irrelevant.
“It seems,” I said, “that, so far as you were concerned, the exhumation was really unnecessary.”
“Quite,” he replied. “It proved nothing that was not already certain. Still, the Commissioner was quite right. For the purposes of a trial, evidence obtained from the actual body of the victim is of immeasurably more weight than indirect scientific evidence, no matter how complete. An ordinary juryman might have difficulty in realizing that the hair is part of the body and that proof of arsenical deposit in the hair is proof of arsenic in the body. But the mistake that he made, as events turned out, was in refusing to make the arrest until my statements had been confirmed by the autopsy and the analysis. That delay allowed the criminal to escape. Not that I complain. To me, personally, her suicide came as a blessed release from an almost intolerable position. But if I had been in his place, I would have taken no chances. She would have gone to trial and to the gallows.”
“Yes,” I admitted; “that was what justice demanded. But I cannot be thankful enough for the delay that let her escape. Fiend as she was, it would have been a frightful thing to have had to give the evidence that would have hanged her.”
“It would,” he agreed; “and the thought of it was a nightmare to me. However, we have escaped that; and after all, justice has been done.”