Messieurs, c'est les microbes qui auront le dernier mot." (Gentlemen, it is the microbes who will have the last word.)

Blessed is he who carries within himself a God, an ideal, and who obeys it: ideal of art, ideal of science, ideal of the gospel virtues, therein lie the springs of great thoughts and great actions; they all reflect light from the Infinite.

Since the most ancient times, all men, and particularly those who endeavored in the practice of medicine, have brought closer together two natural phenomena of capital importance: illness or fever and fermentation.

Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world.

The role of the infinitely small in nature is infinitely great.

I give them experiments and they respond with speeches.

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