The human body is a magazine of inventions, the patent office, where are the models from which every hint is taken. All the tools and engines on earth are only extensions of its limbs and senses.

He only is rich who owns the day.

Motion or change, and identity or rest, are the first and second secrets of nature: Motion and Rest. The whole code of her laws may be written on the thumbnail, or the signet of a ring.

The religion that is afraid of science dishonors God and commits suicide.

I pray my companion, if he wishes for bread, to ask me for bread, and if he wishes for sassafras or arsenic, to ask me for them, and not to hold out his plate, as if I knew already.

There are not in the world at any one time more than a dozen persons who read and understand Plato:-never enough to pay for an edition of his works; yet to every generation these come duly down, for the sake of those few persons, as if God brought them written in his hand.

In the last analysis, love is only the reflection of a man's own worthiness from other men.