“I am about to tell you, Mr. Holmes, all that actually occurred, for you already know so much that it is clearly to my interest that you should know all. I have already explained the relationship in which I stood to the Tregennis family. For the sake of the sister I was friendly with the brothers. There was a family quarrel about money which estranged this man Mortimer, but it was supposed to be made up, and I afterwards met him as I did the others. He was a sly, subtle, scheming man, and several things arose which gave me a suspicion of him, but I had no cause for any positive quarrel.

“One day, only a couple of weeks ago, he came down to my cottage and I showed him some of my African curiosities. Among other things I exhibited this powder, and I told him of its strange properties, how it stimulates those brain centres which control the emotion of fear, and how either madness or death is the fate of the unhappy native who is subjected to the ordeal by the priest of his tribe. I told him also how powerless European science would be to detect it. How he took it I cannot say, for I never left the room, but there is no doubt that it was then, while I was opening cabinets and stooping to boxes, that he managed to abstract some of the devil's-foot root. I well remember how he plied me with questions as to the amount and the time that was needed for its effect, but I little dreamed that he could have a personal reason for asking.