Heart Motu Cordis" (1628) by the English physician William Harvey. Harvey's book completely describes the systemic circulation and the mechanical force of the heart, leading to an overhaul of the Galenic doctrines. Otto Frank (1865–1944) was a German physiologist; among his many published works are detailed studies of this important heart relationship. Ernest Starling (1866–1927) was an important English physiologist who also studied the heart. Although they worked largely independently, their combined efforts and similar conclusions have been recognized in the name "Frank–Starling mechanism". Although Purkinje fibers and the bundle of His were discovered as early as the 19th century, their
Pulmonary circulation precise role of the lungs. The next addition to the human understanding of pulmonary circulation came with the Ancient Greeks. The physician Alcmaeon (520 - 450 BCE) proposed that the brain, not the heart, was the connection point for all of the vessels in the body. He believed that the function of these vessels was to bring the spirit (pneuma) and air to the brain. Empedocles (492 - 432 BCE), a philosopher, proposed a series of pipes impermeable to blood but continuous with blood vessels which carried the pneuma throughout the body. He proposed that this spirit was internalized with