There is no such thing as applied science, only the application of pure science.

There is a time in every man's life when he looks to his God, when he looks at his life, when he wonders how he will be remembered.

Whether our efforts are, or not, favored by life, let us be able to say, when we come near to the great goal, I have done what I could.

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.

How do you know that the incessant progress of science will not compel scientists to consider that life has existed during eternity, and not matter?

Without theory, practice is but routine born of habit. Theory alone can bring forth and develop the spirit of invention. ... [Do not] share the opinion of those narrow minds who disdain everything in science which has not an immediate application. ... A theoretical discovery has but the merit of its existence: it awakens hope, and that is all. But let it be cultivated, let it grow, and you will see what it will become.

Chance favours the trained mind.