The Leather Funnel is a short story by A. Conan Doyle. It is a tale of terror.
The work itself taught me a method of torture which I possibly did not need to know. It is the Water Cure, or the forced consumption of large quantities of water over a short period of time. Doyle sets his story in France, where the method was either 1 gallon or 2 gallons, each designated as a "question" with either ordinary or extraordinary being added to determine the amount of water used. Doyle's victim is a famous murderess who really existed, too.
The story, in some sense, has numerous thematic tensions. There is, of course, the tension between Dacre and the narrator. The narrator, although loving of the abnormal, is not as curious or sick-minded as Dacre. This is told to us, and this is reflected in the narrative. For example, our narrator cannot go through with watching even a drop of water forced into the victim's mouth, but Dacre watched to the final bucket (where he presumably quit). This tension connects, in my mind, with another tension: the tension of epochs of time. When our narrator wakes up, he describes a great joy in being back in the 19th century, where such evils, although real, did not occur. Nevertheless, Dacre's strange mind and the setting of the work (in the housing of Dacre, where it is said that much evil as gone on--even to the point of rituals from black masses) suggests to the reader, almost imperceptibly, that the relief felt is not a true relief.