Who said "The game is afoot!"?

This quote is attributed to Sherlock Holmes.

The game is afoot! - Sherlock Holmes

"The game is afoot!"

Sherlock Holmes Adventure

"Elementary, my dear Watson."

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth."

"I am not a romantic, but I am a realist."

"The mind is the most powerful weapon we possess."

"The greatest adventure is life itself."

"The adventure of life begins with a single step."

"Adventure finds you when you stop running."

"Fortune and glory, kid."