Louis Pasteur

To demonstrate experimentally that a microscopic organism actually is the cause of a disease and the agent of contagion, I know no other way, in the present state of Science, than to subject the microbe (the new and happy term introduced by M. Sédillot) to the method of cultivation out of the body.

The universe is an asymmetrical entity. I am inclined to believe that life as it is manifested to us must be a function of the asymmetry of the universe or of the consequence of this fact. The universe is asymmetrical; for if one placed the entire set of bodies that compose the solar system, each moving in its own way, before a mirror, the image shown would not be superimposable on the reality.

These are the living springs of great thoughts and great actions. Everything grows clear in the reflections from the Infinite.

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.

These three things-work, will, success-fill human existences. Will opens the door to success, both brilliant and happy. Work passes these doors, and at the end of the journey success comes in to crown one's efforts.

Chance favors those who are prepared.

You bring me the deepest joy that can be felt by a man whose invincible belief is that Science and Peace will triumph over Ignorance and War, that nations will unite, not to destroy, but to build, and that the future will belong to those who will have done most for suffering humanity.

There does not exist a category of science to which one can give the name applied science. There are sciences and the applications of science, bound together as the fruit of the tree which bears it.

I am on the edge of mysteries and the veil is getting thinner and thinner.

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.

Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment.

One does not ask of one who suffers: What is your country and what is your religion? One merely says: You suffer, that is enough for me.

It is not the germs we need worry about. It is our inner terrain.

In the fields of observation chance favors only those minds which are prepared.

Let me tell you the secret that has led me to my goal. My strength lies solely in my tenacity.

There does not exist a category of science to which one can give the name applied science. There are science and the applications of science, bound together as the fruit of the tree which bears it.

One must work; one must work. I have done what I could.

Live in the serene peace of laboratories and libraries

Science is the highest personification of the nation because that nation will remain the first which carries the furthest the works of thought and intelligence.

My strength lies solely in my tenacity.

Chance favours a prepared mind.