Chance favours a prepared mind.

The more I know, the more nearly is my faith that of the Breton peasant. Could I but know all I would have the faith of a Breton peasant woman.

Without theory, practice is but routine born of habit. Theory alone can bring forth and develop the spirit of inventions.

Virulence appears in a new light which cannot but be alarming to humanity; unless nature, in her evolution down the ages (an evolution which, as we now know, has been going on for millions, nay, hundreds of millions of years), has finally exhausted all the possibilities of producing virulent or contagious diseases - which does not seem very likely.

The only thing that can bring joy is work.

Intuition is given only to him who has undergone long preparation to receive it.

Did you ever observe to whom the accidents happen? Chance favors only the prepared mind.