"But I found nothing in her things, nor did I discover anything in the library. It seems to me, therefore, that we must look for a direct human agency."

A thought struck me and I hastened to suggest it. "Could some device have been arranged in her clothes, Craig; something like the poison rings of the Middle Ages, a tiny metal thing to spring open and expose its point when pressed against her in the action of the scenes?"

"That occurred to me at the time. That's why I asked Mackay to send all her clothes down here, every stitch and rag of them. I've gone over everything already this morning. Not only have I examined the various materials for stains, but I've tested each hook and eye and button and pin. I've been very careful to cover that possibility."

"You think, then, she was scratched deliberately by some one during the taking of the scenes?"

"If you've followed my line of reasoning you will see that we are driven to that assumption. Perhaps later I will make tests on a given number of girls of Stella's general age and type and temperament to show that they will cry out at the unexpected prick of a fine needle. It's illogical to expect that a cry from Miss Lamar, even an exclamation, would have passed unnoticed except during the excitement of actual picture taking."

Another inspiration came to me, but I was almost afraid to voice it. It seemed a daring theory. "Could death have resulted from poison administered in some other fashion, by something she had eaten, for instance?" I ventured. "Couldn't the scratch be coincidental?"

Kennedy shook his head. "There's the value of our chemical analysis and scientific tests. Her stomach contents showed nothing except as they might have been affected by her weakened condition. From Doctor Blake's report—and he found no ordinary symptoms, remember—and from my own observation, too, I can easily prove in court that she was killed by the mark which was so small that it escaped the physician altogether."

I turned away. Once more Kennedy's reasoning seemed to be leading into a maze of considerations beyond me. How could the deductive method produce results in a case as mysterious as this?

"Having determined that Miss Lamar received the inoculation during the making of one of the scenes, as nearly as we can do so," Kennedy went on, "suppose we take the scenes in order, one at a time, from the last photographed to the first, analyzing each in turn. Remember that we seek a situation where there is not only an opportunity to jab her with a needle, but one in which an outcry would be muffled or inaudible."

I now saw that Kennedy had brought in the bound script of the story, "The Black Terror," and I wondered again, as I had often before, at his marvelous capacity for attention to detail.