Of all ghosts the ghosts of our old loves are the worst.

Healthy scepticism is the basis of all accurate observation.

My name is Sherlock Holmes. It is my business to know what other people do not know.

'It is my duty to warn you that it will be used against you,' cried the Inspector, with the magnificent fair play of the British criminal law.

Jealousy is a strange transformer of characters.

It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.

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