By a man's finger-nails, by his coat-sleeve, by his boots, by his trouser-knees, by the callosities of his forefinger and thumb, by his expression, by his shirt-cuff — By each of these things a man's calling is plainly revealed. That all united should fail to enlighten the competent inquirer in any case is almost inconceivable. You know that a conjurer gets no credit when once he has explained his trick; and if I show you too much of my method of working, you will come to the conclusion that I am a very ordinary individual after all.

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.

When the impossible has been eliminated, all that remains no matter how improbable is possible.

A fine horse or a beautiful woman, I cannot look at them unmoved, even now when seventy winters have chilled my blood.

Crime is common. Logic is rare. Therefore it is upon the logic rather than upon the crime that you should dwell.

I think there are certain crimes which the law cannot touch, and which therefore, to some extent, justify private revenge.

The Press, Watson, is a most valuable institution, if you only know how to use it.