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

The motive power is the cause of all life.

This work should commence with the conception of man, and should describe the nature of the womb, and how the child inhabits it, and in what stage it dwells there, and the manner of its quickening and feeding, and its growth, and what interval there is between one stage of growth and another, and what thing drives it forth from the body of the mother, and for what reason it sometimes emerges from the belly of its mother before the due time.

The water which rises in the mountains is the blood which keeps the mountain in life.

I say that in narrative paintings one should mingle direct contraries close by, because they produce strong contrasts with one another, and all the more so when they are very close together; that is, the ugly next to the beautiful, the big to the small, the old to the young, the strong to the weak; in this way you will vary as much as possible and close by.

You must grow in patience when you meet with great wrongs, and they will then be powerless to vex your mind.

Where there is most feeling, there is the greatest martyrdom.