"How do you know that?
"I followed you."
"I saw no one."
"That is what you may expect to see when I follow you."
- "The Adventure of the Devil's Foot"Monsignor Ronald Knox, in his landmark "Studies in the Literature of Sherlock Holmes," cited that bit of dialogue between Dr. Leon Sterndale and Holmes as an example of what he called "Sherlockismus."
Another great Sherlockian, Anthony Boucher, alluded to this passage in his first Sister Ursula novel, Nine Times Nine, originally published under his H.H. Holmes pseudonym.
Here's the dialogue among Lt. Terence Marshall, his wife Leona, and protagonist Matt Duncan. Marshall speaks first:
"There's a passage I remember in one of the Holmes stories -- "
"I thought you didn't like mysteries," said Leona.
"Hell, darling, Sherlock Holmes isn't just mysteries, anymore than Macbeth is just a play or Bist du bei mir is just a tune. The Holmes chronicles are something wonderful and superhuman and apart. I grew up on them and I worship at the shrine."
"I'll agree they aren't mysteries," said Leona, with a noticeable absence or her husband's enthusiasm.
"Anybody that'll hold out clews on you like that --"
"This passage now," Matt suggested.
"I think it's in The Lion's Mane. The explorer says, 'I saw no one,' and Holmes replies, 'That is what you may expect to see when I follow you.' Well, that's the ideal of all shadowing. We aren't all Holmeses in the police force, but nobody should let a man notice he's being followed."
All that is very nice, but here's my question: Was it Lt. Marshall who got the wrong story as the origin of that great passage of Sherockismus, or was it Anthony Boucher - famed mystery writer, critic, and member of the Baker Street Irregulars?