A Treatise on Painting, by Leonardo da Vinci
Senex and Taylor, London
A Painter well acquainted with the Theory of his Art, may without any great difficulty render himself Universal. For all terrestrial Animals have this in Common with each other, that their Members are composed of Muscles, Nerves, and Bones; the only Difference between them lying in their different Lengths, and Thicknesses, as is demonstrated by the Anatomists. As to Aquatick Animals, in which indeed there is a great Variety, I think a Painter who is well advis'd, will not trouble himself about them.