Yet birth, and lust, and illness, and death are changeless things, and when one of these harsh facts springs out upon a man at some sudden turn of the path of life, it dashes off for the moment his mask of civilization and gives a glimpse of the stranger and stronger face below.

Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.

I had ... come to an entirely erroneous conclusion, which shows, my dear Watson, how dangerous it always is to reason from insufficient data.

There is nothing more stimulating than a case where everything goes against you.

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

It may be that you are not yourself luminous, but that you are a conductor of light. Some people without possessing genius have a remarkable power of stimulating it.

When you have eliminated the impossible, what is left, no matter how unlikely, is the truth.