William Harvey's Sun Metaphor

2 Pages 408 Words

According to William Harvey in his Anatomical Studies on the Motion of the Heart and Blood, “…the heart is the center of life, the sun of the Microcosm, as the sun itself might be called the heart of the world” (71). Just prior to this claim in the text, Harvey describes the process in which “moist earth warmed by the sun gives off vapors, which, rising, are condensed to fall again moistening the earth” (70-71). Thus, Harvey’s analogy, likening the human heart to the sun, conveys the central notion of his work: the heart and blood in the human body comprise a system that, much like the water cycle, is unified and self-perpetuating.
Harvey describes the heart’s role within the human body as a powerhouse, a source of energy and nutrition that approximates the sun’s role in the water cycle. He writes: “The blood is moved, invigorated, and kept from decaying by the power and pulse of the heart…whose function is the nourishing and warming of the whole body, the basis and source of all life” (71). Thus, Harvey characterizes the heart as the foundation upon which the system depends.
Harvey’s text slowly and methodically proceeds toward the conclusion that a fixed amount of blood is pumped throughout the body by the heart. He makes the crucial point that “unless you deny what you see, you must admit the blood returns to the heart” (83). Harvey accomplishes this in part by quantitatively examining the amount of blood that passes through the veins and arteries. He determines that such a large quantity of blood could not be furnished by the consumption of food alone because “blood is continually poured into the arteries in a greater amount than can be supplied by the food” (82). Harvey’s meticulous experimentation results in his conclusion that the blood in the human body is in continuous circulation, rather than continually being produced and used up: “Since it all flows past in so short a time, it ...