If you and your child were going to be killed tomorrow, would you not give him to eat today?

Anyone who has obeyed nature by transmitting a piece of gossip experiences the explosive relief that accompanies the satisfying of a primary need.

Conquering matter is to understand it, and understanding matter is necessary to understanding the universe and ourselves: and that therefore Mendeleev's Periodic Table, which just during those weeks we were learning to unravel, was poetry.

It is the duty of righteous men to make war on all undeserved privilege, but one must not forget that this is a war without end.

An enemy who sees the error of his ways ceases to be an enemy.

I live in my house as I live inside my skin: I know more beautiful, more ample, more sturdy and more picturesque skins: but it would seem to me unnatural to exchange them for mine.

Did chemistry theorems exist? No: therefore you had to go further, not be satisfied with the quia, go back to the origins, to mathematics and physics. The origins of chemistry were ignoble, or at least equivocal: the dens of the alchemists, their abominable hodgepodge of ideas and language, their confessed interest in gold, their Levantine swindles typical of charlatans and magicians; instead, at the origin of physics lay the strenuous clarity of the West-Archimedes and Euclid.