"Indeed," said Holmes. "Was it your custom always to lock yourselves in at night?"
"Always."
"And why?"
"I think that I mentioned to you that the doctor kept a cheetah and a baboon. We had no feeling of security unless our doors were locked."
"Quite so. Pray proceed with your statement."
"I could not sleep that night. A vague feeling of impending misfortune impressed me. My sister and I, you will recollect, were twins, and you know how subtle are the links which bind two souls which are so closely allied. It was a wild night. The wind was howling outside, and the rain was beating and splashing against the windows. Suddenly, amid all the hubbub of the gale, there burst forth the wild scream of a terrified woman. I knew that it was my sister's voice. I sprang from my bed, wrapped a shawl round me, and rushed into the corridor. As I opened my door I seemed to hear a low whistle, such as my sister described, and a few moments later a clanging sound, as if a mass of metal had fallen. As I ran down the passage, my sister's door was unlocked, and revolved slowly upon its hinges. I stared at it horror-stricken, not knowing what was about to issue from it. By the light of the corridor-lamp I saw my sister appear at the opening, her face blanched with terror, her hands groping for help, her whole figure swaying to and fro like that of a drunkard. I ran to her and threw my arms round her, but at that moment her knees seemed to give way and she fell to the ground.
She writhed as one who is in terrible pain, and her limbs were dreadfully convulsed. At first I thought that she had not recognised me, but as I bent over her she suddenly shrieked out in a voice which I shall never forget, 'Oh, my God! Helen! It was the band! The speckled band!' There was something else which she would fain have said, and she stabbed with her finger into the air in the direction of the doctor's room, but a fresh convulsion seized her and choked her words. I rushed out, calling loudly for my stepfather, and I met him hastening from his room in his dressing-gown. When he reached my sister's side she was unconscious, and though he poured brandy down her throat and sent for medical aid from the village, all efforts were in vain, for she slowly sank and died without having recovered her consciousness. Such was the dreadful end of my beloved sister."
"One moment," said Holmes, "are you sure about this whistle and metallic sound? Could you swear to it?"