William Harvey (1578–1657), the first person to describe the circulation of blood, would not think of himself as a poet, but he was a writer, a philosopher (a follower of Aristotle), and a performer, conducting public dissections. But I think that I have found a poem in Harvey’s great work, Exercitatio anatomica de motu cordis et sanguinis in animalibus (An Anatomical Essay Concerning the Movement of the Heart and the Blood in Animals).

It’s hard for us now, when blood circulation is known to all, to grasp the radicality of Harvey’s discovery. For millennia doctors had followed the teachings of the Greek physician Galen. What follows is what they and Galen believed. I’ve taken this from Roy Porter’s great book The Greatest Benefit to Mankind: A Medical History of Humanity from Antiquity to the Present:

“In traditional Galenic physiology there were two types of blood, the venous and the arterial, with distinct pathways and functions, relating to the three chief body centres: the liver (responsible for nutrition and growth), the heart (vitality), and the brain (sensation and reason). Nourishment and growth were secured by the venous blood originating in the liver, while vitality was conveyed to the body parts by the arterial blood originating in the heart. Arterial (life-giving) blood contained pneuma (spirituous air) and blood; and, like venous blood, was thought to spread to all parts of the body when needed, being there used up; it did not return to the heart. Given the quite distinct functions of venous and arterial blood, their different sources, and the belief that they were expended, there was no question of the blood circulating around the body. The heart did not even drive blood through the arteries – for Galen the active phase of the heart’s motion was diastole (dilation), when, like a bladder filling, it sucked blood in. The heart did not pump blood out; the blood’s movement through the arteries was explained by an innate ‘pulsative faculty’ in the arteries themselves.”

In case you need reminding the strongly muscular left ventricle of the heart pumps oxygenated blood through the aorta and other arteries to all parts of the body. The arteries branch repeatedly until they become the microscopic capillaries where oxygen passes from the haemoglobin in the red blood cells to the tissues of the body. The deoxygenated blood flows on as the capillaries come together to form veins that carry blood back to the right side of the heart. The right ventricle pumps the deoxygenated blood through the pulmonary artery to the capillaries in the lungs, where the blood is reoxygenated and passed back through the pulmonary artery to the left side of the heart for the cycle to begin again. My heart has done this some 350 times while I’ve been writing this paragraph.

Because Harvey contradicted Galen, there were many who dismissed his ideas, but eventually Harvey’s description displaced that of Galen..

In the found poem Harvey sees the heart as the Sun of the body moving and perfecting the blood and nourishing, cherishing and vegetating (feeding?) the body and being “author of all.” I was initially bothered that I wasn’t clear when Harvey was writing about the Sun in the heavens and the Sun as the heart of our body, but now I think that the confusion adds to both.

The heart, although still associated strongly with love, has been downgraded to being thought simply a pump, albeit a remarkable one that can sometimes beat for a century without repair, and the brain is considered a superior organ if not “author of all.”

The heart is the Sun of the body

The heart is the beginning of life,

The Sun of the Microcosm.

And as the Sun

Deserves to be call’d the heart of the world,

By whose virtue, and pulsation,

The blood is mov’d, perfected,

And defended from corruption, and mattering;

And this familiar household-god doth his duty to the whole body,

By nourishing, cherishing, and vegetating,

Being the foundation of life, and author of all.