Illustration of human viscera by Paulo Mascagni. "Exploded thorax." Paolo Mascagni was Prosector of Anatomy at the University of Siena, which meant he was responsible for leading dissection for demonstration and research. His "Anatomia Universa" was a comprehensive work of anatomy with forty-four hand colored plates. The main figure here is surrounded by smaller studies. At the top of the plate, the hearts have had the "epicardium," the outer layer of heart tissue, removed to reveal the cardiac muscle. The heart at the bottom left is viewed from above to reveal the aortic valve. The smaller figures are fetal dissections revealing the umbilical artery and vein. Colored engraving, c. 1823-1833.