I consider that a man's brain originally is like a little empty attic, and you have to stock it with such furniture as you choose. [...] It is a mistake to think that that little room has elastic walls and can distend to any extent. [...] It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.

How sweet the morning air is! See how that one little cloud floats like a pink feather from some gigantic flamingo. Now the red rim of the sun pushes itself over the London cloud-bank. It shines on a good many folk, but on none, I dare bet, who are on a stranger errand than you and I. How small we feel with our petty ambitions and strivings in the presence of the great elemental forces of Nature!

Problems may be solved in the study which have baffled all those who have sought a solution by the aid of their senses. To carry the art, however, to its highest pitch, it is necessary that the reasoner should be able to use all the facts which have come to his knowledge; and this in itself implies, as you will readily see, a possession of all knowledge, which, even in these days of free education and encyclopaedias, is a somewhat rare accomplishment.

Heaven, too, was very near to them in those days. God's direct agency was to be seen in the thunder and the rainbow, the whirlwind and the lightning. To the believer, clouds of angels and confessors, and martyrs, armies of the sainted and the saved, were ever stooping over their struggling brethren upon earth, raising, encouraging, and supporting them.

He [Professor Moriarty] is the Napoleon of crime, Watson. He is the organizer of half that is evil and of nearly all that is undetected in this great city. He is a genius, a philosopher, an abstract thinker. He has a brain of the first order.

There is a soul-jealousy that can be as frantic as any body-jealousy.

Every man finds his limitations, Mr. Holmes, but at least it cures us of the weakness of self-satisfaction.