“The Adventure of the Devil’s Foot”, published in 1910, is the 43rd Sherlock Holmes story. Holmes is persuaded to take a holiday in Cornwall. One morning, he is visited by Mortimer Tregennis who has just found his sister dead and his two brothers in a state close to madness. All three were still around the table, in the room where Mortimer had left them the previous evening and no one seems to have entered the room.
After Mortimer Tregennis dies in the same room, Holmes rushes to the scene of the crime to collect clues. Holmes and his friend and colleague, Watson, say in the same room to try and solve the crime ….
I had hardly settled in my chair before I was conscious of a thick, musky odour, subtle and nauseous. At the very first whiff of it my brain and my imagination were beyond all control. A thick, black cloud swirled before my eyes, and my mind told me that in this cloud, unseen as yet, but about to spring out upon my appalled senses, lurked all that was vaguely horrible, all that was monstrous and inconceivably wicked in the universe. Vague shapes swirled and swam amid the dark cloud-bank, each a menace and a warning of something coming, the advent of some unspeakable dweller upon the threshold, whose very shadow would blast my soul. A freezing horror took possession of me. I felt that my hair was rising, that my eyes were protruding, that my mouth was opened, and my tongue like leather. The turmoil within my brain was such that something must surely snap.I tried to scream and was vaguely aware of some hoarse croak which was my own voice, but distant and detached from myself.