Diagram Showing the Pumping of the Heart
Diagram to illustrate the action (pumping) of the heart. Labels: aur., auricle; vent., ventricle; v, veins; a, aorta; m, mitral valve; s, semilunar valves. In A, auricle contracting, ventricle dilated, mitral valve open, semilunar valves closed. In B, auricle dilated, ventricle contracting, mitral valve closed, semilunar valves open.
Martin, H. Newell The Human Body: A Text-book of Anatomy, Physiology and Hygiene (New York: Henry Holt and Company, 1900) 182