To know how to wonder and question is the first step of the mind toward discovery.

Chance favours the trained mind.

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.

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

... by chance you will say, but chance only favors the mind which is prepared.

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

These microscopic organisms form an entire world composed of species, families and varieties whose history, which has barely begun to be written, is already fertile in prospects and findings of the highest importance. The names of these organisms are very numerous and will have to be defined and in part discarded. The word microbe which has the advantage of being shorter and carrying a more general meaning, and of having been approved by my illustrious friend, M. Littré, the most competent linguist in France, is one we will adopt.