Doctor McMurray obeyed. He went into the pantry, and there on a shelf stood two wide-mouthed bottles, very much alike save that one had never been opened. He looked at them in silent wonderment, not knowing for the instant what message they conveyed. He picked them up and read the labels; then he had an inkling of what they meant, for one was marked "Arsenic," the other "Epsom Salts." He went back to Mrs. Trent.
"You think there has been a mistake?" he said softly.
Mrs. Trent raised her head from her hands. Her voice was strained and unnatural as she answered:
"I know there has been a mistake, and I know that I made it."
"Tell me why."
"It is very simple. They sent up from Mr. Withey's that last night for some Epsom salts in a great hurry. I knew there must be some great need, so I rushed to the pantry. Jacob wasn't at home. I reached to the top shelf and pulled down a bottle, one of those bottles. In my hurry I didn't look at the label, but poured the little white crystals out in a paper, and they took them away. Then I put the bottle back in its place and went on with my work. In the morning I heard Mr. Withey was dead."
"But the arsenic—the arsenic," interposed the doctor. "How did it get there?"
"Heaven knows; you remember Jacob used to get it once in a while to keep his horses in condition. I presume he got a fresh bottle of it about the same time I got some more Epsom salts, and they were both put up there on the top shelf together. It is all too plain. I got the bottles mixed and opened the wrong one."
"And so Jacob was innocent?"
"Yes, and I could have saved him if I had known in time. Oh, Jacob,
Jacob," she moaned, compressing a world of remorse into the words.
"And it was my mistake—my mistake!"