It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change.

The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an agnostic.
A scientific man ought to have no wishes, no affections, - a mere heart of stone.

The highest possible stage in moral culture is when we recognize that we ought to control our thoughts.

If the misery of the poor be caused not by the laws of nature, but by our institutions, great is our sin.

An American monkey, after getting drunk on brandy, would never touch it again, and thus is much wiser than most men.

A man's friendships are one of the best measures of his worth.

We must, however, acknowledge, as it seems to me, that man with all his noble qualities... still bears in his bodily frame the indelible stamp of his lowly origin.