Every bough and every fruit is born above the insertion of its leaf, which serves it as a mother, giving it water from the rain and moisture from the dew which falls on it from above in the night, and often it shields them from the heat of the sun's rays. Therefore, O painter, who lackest such rules, be desirous, in order to escape the blame of those who know, of copying every one of thy objects from nature, and despise not study after the manner of those who work for gain.
On Anatomy
62.
And you who say that it would be better to see practical anatomy than drawings of it, would be right if it were possible to see all the things which are shown in such drawings in a single drawing, in which you, with all your skill, will not see nor obtain knowledge of more than a few veins; and to obtain true and complete knowledge of these veins I have destroyed more than ten human bodies, destroying all the other limbs, and removing, down to its minutest particles, the whole of the flesh which surrounds these veins, without letting them bleed save for the insensible bleeding of the capillary veins. And as one body did not suffice for so long a time I had to proceed with several bodies by degrees until I finished by acquiring perfect knowledge, and this I repeated twice to see the differences. And if you have a love for such things you may be prevented by disgust, and if this does not prevent you, you may be prevented by fear of living at night in company with such corpses, which are cut up and flayed and fearful to see; and if this does not prevent, you may not have a sufficient mastery of drawing for such a demonstration, and if you have the necessary mastery of drawing, it may not be combined with the knowledge of perspective; and if it were you might lack the power of geometrical demonstration, and the calculation of forces, and of the strength of the muscles, and perhaps you will lack patience and consequently diligence. As to whether these qualities are to be found in me or not the hundred and twenty books I have composed will pronounce the verdict Yes or No. Neither avarice nor negligence, but time has hindered me in these. Farewell.
On Study
63.
I have myself proved that it is useful when you are in bed in the dark to work with the imagination, summing up the external outlines of the forms previously studied or other noteworthy things apprehended by subtle speculation; and this is a laudable practice and useful in impressing objects on the memory.
On judging Pictures
64.