No, there is now no circumstance known in which it can be affirmed that microscopic beings came into the world without germs, without parents similar… - Louis Pasteur

God grant that by my persevering labours I may bring a little stone to the frail and ill-assured edifice of our knowledge of those deep mysteries of Life and Death where all our intellects have so lamentably failed.

Où sont les vraies sources de la dignité humaine, de la liberté et de la démocratie moderne, sinon dans la notion de l’infini devant laquelle tous les hommes sont égaux?

Though one discovery always surpasses another, and though the chemical and physical knowledge accumulated since his time has gone beyond all Lavoisier's dreams, his work, like that of Newton and a few other rare spirits, will remain ever young. Certain details will age, as do the fashions of another time, but the foundation, the method, constitute one of those great aspects of the human mind, the majesty of which is only increased by years.