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

Luck favors the mind that is prepared.

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

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.

How do you know that the incessant progress of science will not compel scientists to consider that life has existed during eternity, and not matter?

If it is a terrifying thought that life is at the mercy of the multiplication of these minute bodies [microbes], it is a consoling hope that Science will not always remain powerless before such enemies.

If science has no country, the scientist should have one, and ascribe to it the influence which his works may have in this world.