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

Truth was the only daughter of Time.

The mind that engages in subjects of too great variety becomes confused and weakened.

Who would believe that so small a space could contain the images of all the universe?

O speculators about perpetual motion, how many vain chimeras have you created in the like quest? Go and take your place with the seekers after gold.

Nature alone is the master of true genius.

One has no right to love or hate anything if one has not acquired a thorough knowledge of its nature. Great love springs from great knowledge of the beloved object, and if you know it but little you will be able to love it only a little or not at all.