The first point of courtesy must always be truth.

A friend is a person with whom I may be sincere. Before him I may think aloud.

The student is to read history actively and not passively; to esteem his own life the text, and books the commentary. Thus compelled, the muse of history will utter oracles as never to those who do not respect themselves.

It does not need that a poem should be long. Every word was once a poem.

I hate the prostitution of the name of friendship to signify modish and worldly alliances.

The essence of age is intellect. Wherever that appears, we call it old.

The earth is a machine which yields almost gratuitous service to every application of intellect. Every plant is a manufacturer of soil. In the stomach of the plant development begins. The tree can draw on the whole air, the whole earth, on all the rolling main. The plant is all suction-pipe,--imbibing from the ground by its root, from the air by its leaves, with all its might.