Do not put forward anything that you cannot prove by experimentation.

The grandeur of the acts of men are measured by the inspiration from which they spring.

Time is the best appraiser of scientific work, and I am aware that an industrial discovery rarely produces all its fruit in the hands of its first inventor.

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

The nights seem to me too long... I am often scolded by Madame Pasteur, but I tell her I shall lead her to fame.

The Ancients understood the omnipotence of the underside of things.

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.

After death, life reappears in a different form and with different laws. It is inscribed in the laws of the permanence of life on the surface of the earth and everything that has been a plant and an animal will be destroyed and transformed into a gaseous, volatile and mineral substance.

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

The flavor of wine is like delicate poetry.

Herrmann Pidoux and Armand Trousseau stated 'Disease exists within us, because of us, and through us', Pasteur did not entirely disagree, 'This is true for certain diseases', he wrote cautiously, only to add immediately: 'I do not think that it is true for all of them'.

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.

Every chemical substance, whether natural or artificial, falls into one of two major categories, according to the spatial characteristic of its form. The distinction is between those substances that have a plane of symmetry and those that do not. The former belong to the mineral, the latter to the living world.

Bernard was right. The germ is nothing, the terrain is everything.

It is a matter of fact; I approached without a preconceived idea, too ready to declare, if the experiment had imposed upon me the confession, that there was a spontaneous generation, of
which I am convinced today that those who assure it are blindfolded.

If you suppress laboratories, physical science will be stricken with barrenness and death.

When I approach a child, he inspires in me two sentiments -- tenderness for what he is and respect for what he may become.

There are no such things as applied sciences, only applications of science.

It is surmounting difficulties that makes heroes.

Chance favors the prepared mind.