Down posted Hilda from Scotland, where she had taken up her abode. She came in March, alone, driving herself in a nimble two–seater. Up the drive she came, tooting up the incline, then sweeping round the oval of grass, where the two great wild beech–trees stood, on the flat in front of the house.

Connie had run out to the steps. Hilda pulled up her car, got out, and kissed her sister.

‘But Connie!’ she cried. ‘Whatever is the matter?’

‘Nothing!’ said Connie, rather shamefacedly; but she knew how she had suffered in contrast to Hilda. Both sisters had the same rather golden, glowing skin, and soft brown hair, and naturally strong, warm physique. But now Connie was thin and earthy–looking, with a scraggy, yellowish neck, that stuck out of her jumper.

‘But you’re ill, child!’ said Hilda, in the soft, rather breathless voice that both sisters had alike. Hilda was nearly, but not quite, two years older than Connie.

‘No, not ill. Perhaps I’m bored,’ said Connie a little pathetically.

The light of battle glowed in Hilda’s face; she was a woman, soft and still as she seemed, of the old amazon sort, not made to fit with men.

‘This wretched place!’ she said softly, looking at poor, old, lumbering Wragby with real hate. She looked soft and warm herself, as a ripe pear, and she was an amazon of the real old breed.

She went quietly in to Clifford. He He thought how handsome she looked, but also he shrank from her. His wife’s family did not have his sort of manners, or his sort of etiquette. He considered them rather outsiders, but once they got inside they made him jump through the hoop.

He sat square and well–groomed in his chair, his hair sleek and blond, and his face fresh, his blue eyes pale, and a little prominent, his expression inscrutable, but well–bred. Hilda thought it sulky and stupid, and he waited. He had an air of aplomb, but Hilda didn’t care what he had an air of; she was up in arms, and if he’d been Pope or Emperor it would have been just the same.

‘Connie’s looking awfully unwell,’ she said in her soft voice, fixing him with her beautiful, glowering grey eyes. She looked so maidenly, so did Connie; but he well knew the tone of Scottish obstinacy underneath.

‘She’s a little thinner,’ he said.

‘Haven’t you done anything about it?’

‘Do you think it necessary?’ he asked, with his suavest English stiffness, for the two things often go together.

Hilda only glowered at him without replying; repartee was not her forte, nor Connie’s; so she glowered, and he was much more uncomfortable than if she had said things.

‘I’ll take her to a doctor,’ said Hilda at length. ‘Can you suggest a good one round here?’

‘I’m afraid I can’t.’

‘Then I’ll take her to London, where we have a doctor we trust.’

Though boiling with rage, Clifford said nothing.

“The vicar knew. He was in our confidence. He would tell you that she was an angel upon earth. That was why he telegraphed to me and I returned. What was my baggage or Africa to me when I learned that such a fate had come upon my darling? There you have the missing clue to my action, Mr. Holmes.”

“Proceed,” said my friend.

Dr. Sterndale drew from his pocket a paper packet and laid it upon the table. On the outside was written “Radix pedis diaboli” with a red poison label beneath it. He pushed it towards me. “I understand that you are a doctor, sir. Have you ever heard of this preparation?”

“Devil’s-foot root! No, I have never heard of it.”

“It is no reflection upon your professional knowledge,” said he, “for I believe that, save for one sample in a laboratory at Buda, there is no other specimen in Europe. It has not yet found its way either into the pharmacopaeia or into the literature of toxicology. The root is shaped like a foot, half human, half goatlike; hence the fanciful name given by a botanical missionary. It is used as an ordeal poison by the medicine-men in certain districts of West Africa and is kept as a secret among them. This particular specimen I obtained under very extraordinary circumstances in the Ubangi country.” He opened the paper as he spoke and disclosed a heap of reddish-brown, snuff-like powder.

“Well, sir?” asked Holmes sternly.

“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 hi 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.

“I thought no more of the matter until the vicar’s telegram reached me at Plymouth. This villain had thought that I would be at sea before the news could reach me, and that I should be lost for years in Africa. But I returned at once. Of course, I could not listen to the details without feeling assured that my poison had been used. I came round to see you on the chance that some other explanation had suggested itself to you. But there could be none. I was convinced that Mortimer Tregennis was the murderer; that for the sake of money, and with the idea, perhaps, that if the other members of his family were all insane he would be the sole guardian of their joint property, he had used the devil’s-foot powder upon them, driven two of them out of their senses, and killed his sister Brenda, the one human being whom I have ever loved or who has ever loved me. There was his crime; what was to be his punishment?