The greatest gift is a portion of thyself.

The most useful man in the most useful world, so long as only commodity was served, would remain unsatisfied. But, as fast as he sees beauty, life acquires a very high value.

In science we have to consider two things: power and circumstance.

Do not be too timid and squeamish about your actions.

[on Thoreau:] For not a particle of respect had he to the opinions of any man or body of men, but homage solely to truth itself.

Nature has her own best mode of doing each thing, and she has somewhere told it plainly, if we will keep our eyes and ears open. If not, she will not be slow in undeceiving us, when we prefer our own way to hers.

Never self-possessed, or prudent, love is all abandonment.