Avoid studies of which the result dies with the worker.

If you find from your own experience that something is a fact and it contradicts what some authority has written down, then you must abandon the authority and base your reasoning on your own findings.

In life beauty perishes, but not in art.

Painting is poetry that is seen rather than felt, and poetry is painting that is felt rather than seen.

And you who wish to represent by words the form of man and all the aspects of his membrification, relinquish that idea. For the more minutely you describe the more you will confine the mind of the reader, and the more you will keep him from the knowledge of the thing described. And so it is necessary to draw and to describe.

If you do not rest on the good foundation of nature, you will labour with little honor and less profit.

There is no higher or lower knowledge, but one only, flowing out of experimentation.