In the relations of man with the animals, with the flowers, with all the objects of creation, there is a whole great ethic, scarcely perceived as yet, which will at length break through into the light, and which will be the corollary and the complement to human ethics.

Revery, which is thought in its nebulous state, borders closely upon the land of sleep, by which it is bounded as by a natural frontier.

There are moments when a rope's end, a pole, the branch of the tree, is life itself, and it is a frightful thing to see a living being lose his hold upon it, and fall like a ripe fruit.

Daring is the price of progress. All splendid conquests are the prize of boldness, more or less.

Sleep comes more easily than it returns.

All the human and animal manure which the world wastes, if returned to the land, instead of being thrown into the sea, would suffice to nourish the world.

Progress is the life-style of man.