O neglectful Nature, wherefore art thou thus partial, becoming to some of thy children a tender and benignant mother, to others a most cruel and ruthless stepmother? I see thy children given into slavery to others without ever receiving any benefit, and in lieu of any reward for the services they have done for them they are repaid by the severest punishments.

The poet ranks far below the painter in the representation of visible things, and far below the musician in that of invisible things.

Depth and strength of a human character are defined by its moral reserves.

Oh! Speculators on things, boast not of knowing the things that nature ordinarily brings about; but rejoice if you know the end of those things which you yourself device.

Drawing is based upon perspective, which is nothing else than a thorough knowledge of the function of the eye.

To speak well of a base man is much the same as speaking ill of a good man.

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