What does "Devil's foot" mean ?

Question

one adventure of sherlock holmes name is devil foot , does it mean devil's dance or parade or devil's trace or sth else ? please help about the meaning .

Answer 1

a short glimpse is here...

Holmes and Dr. Watson find themselves in Cornwall one spring for the former’s health, but the holiday ends with a bizarre event. Mr. Mortimer Tregennis, a local gentleman, and Mr. Roundhay, the local vicar, come to Holmes to report that Tregennis’s two brothers have gone mad, and his sister has died. Tregennis had gone to visit them in their village (Tredannick Wollas), played whist with them, and then left. When he came back this morning, he found them still sitting in their places at the table, the brothers, George and Owen, laughing and singing, and the sister, Brenda, dead. The housekeeper had discovered them in this state, and fainted. The vicar has not been to see yet. Tregennis says that he remembers one brother looking through the window, and then he himself turned to see some “movement” outside.

Mortimer Tregennis was once estranged from his siblings by the matter of dividing the proceeds from the sale of the family business, but he insists that all was forgiven, although he still lives apart from them. Indeed, everyone seemed to be in perfectly high spirits last night, and it is a mystery why Brenda died with such a ghastly look of horror on her face. The doctor who was summoned reckoned that she had been dead for six hours. He also collapsed into a chair for a while after arriving.

Holmes goes to the house in question and, apparently carelessly, kicks over a watering pot, soaking everyone’s feet. The housekeeper tells Holmes that she heard nothing in the night, and that the family had been particularly happy and prosperous lately. Holmes observes the remains of a fire in the fireplace. Tregennis explains that it was a cold, damp night.

Answer 2

its a plant called Radix pedis diaboli (“Devil’s-foot root” in Latin) that produces the poison killing the trengennis family.