Chapter 13 THE MYSTERIOUS MR. OBSERVER

Observation tells me that you have a little reddish mold adhering to

your instep. . . . So much is observation. The rest is deduction.

-Sherlock Holmes.

Sign of Four (Doyle).

In Prehistoric Days, when one man hied himself from his cave to impress his ideas upon another the persuasion used took the form of a wallop on the head with a sto