The greatest geniuses sometimes accomplish more when they work less.

One day the world will look upon research upon animals as it now looks upon research on human beings.

When counting, try not to mix chickens with blessings.

He who has access to the fountain does not go to the water-pot.

Experience, the interpreter between creative nature and the human race, teaches the action of nature among mortals: how under the constraint of necessity she cannot act otherwise than as reason, who steers her helm, teaches her to act.

No human investigation can claim to be scientific if it doesn't pass the test of mathematical proof.

Of several bodies, all equally large and equally distant, that which is most brightly illuminated will appear to the eye nearest and largest.