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.

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

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

There is no such thing as a special category of science called applied science; there is science and its applications, which are related to one another as the fruit is related to the tree that has borne it.

Oh my goodness the mystery that has prompted my objective. My quality lies exclusively in my tirelessness.

When you believe you have found an important scientific fact, and are feverishly curious to publish it, constrain yourself for days, weeks, years sometimes, fight yourself, try and ruin your own experiments, and only proclaim your discovery after having exhausted all contrary hypotheses. But when, after so many efforts you have at last arrived at a certainty, your joy is one of the greatest which can be felt by a human soul.

Fortune favors the well-prepared.