There is nothing as deceptive as an obvious fact

There is nothing more deceptive than an obvious fact.

Dear me, Watson, is it possible that you have not penetrated the fact that the case hangs upon the missing dumb-bell?

There is nothing more unaesthetic than a policeman.

Nothing clears up a case so much as stating it to another person.

Mediocrity knows nothing higher than itself, but talent instantly recognizes genius.