Leonardo da Vinci was the first artist to produce true scientific depictions of many bodily organs, writes Prof William Reville
Leonardo da Vinci (1452-1519) was born to unmarried parents Ser Piero, a notary, and Catarina, a peasant woman. He lived his early life around Vinci, near Florence, first with his mother and later in the house of his father, uncle and grandfather. His uncle stimulated his interest in scientific observation and his grandfather's keeping of journals established a habit Leonardo followed all his life.
In 1466 Leonardo was apprenticed as a painter in the Florentine workshop of the artist Verrocchio. Painting was regarded as a lowly trade, fit for the sons of artisans and lowly peasants and Leonardo's "illegitimate" birth made him ineligible for the "respectable" professions. With minimal formal education Leonardo didn't fit into the highbrow literary culture of the Medicis and, outside of his creative art, he naturally turned towards observation and science. Despite these, and other, circumstantial impediments, Leonardo developed into possibly the greatest all round genius the world has known.
Leonardo wrote his journals daily and also kept separate sheets of observations. More than 5,000 pages survive. Most are written backwards in mirror script and are dense with drawings. Leonardo recorded his observations on acoustics, anatomy, botany, engineering, geology, hydraulics, hydrodynamics, mathematics, music, optics, together with plans for many inventions including flying machines, bicycle, tank, machine-gun, diving suit, parachute, folding bed, contact lenses, water-powered alarm clock, and much more. The Codex Leicester, soon to be on display at the Chester Beatty Library, is one of Leonardo's most important scientific notebooks. It deals mainly with the movement and nature of water. Light is a secondary subject of the codex and there are notes on astronomy, meteorology and geology, and designs for bridges and flood-control.
Leonardo began formal study of human topographical anatomy when apprenticed to Verrocchio and his continued studies are demonstrated by many drawings in the journals. His most famous drawing, Vitruvian Man, illustrating how human bodily proportions fit perfectly into a circle or a square, has come to symbolise Renaissance humanism.
As he gained artistic renown, Leonardo was given permission to dissect human corpses at the hospital Santa Maria Novella in Florence. He discovered structures and functions that would not be understood by others for generations. Leonardo was the first to describe the double S form of the human backbone. He studied the inclination of the pelvis and sacrum and noted the sacrum was made of five fused vertebrae. He drew cross-sections of the brain. He was the first to draw the human appendix and also drew the lungs, urinary tract and the sex and other organs. He was one of the first to draw a scientific representation of the foetus in the uterus. He studied the heart and vascular system in detail.
Let me quote Leonardo regarding two autopsies. This is the first description of arteriosclerosis in the history of medicine: "This old man told me that he had lived 100 years, and that he felt no physical pain, only weakness; and thus seated on a bed in the hospital of Santa Maria Novella, without any movement or symptom of distress he gently passed from life into death. I carried out an autopsy to determine the cause of such a calm death and discovered it was the result of weakness produced by insufficiency of blood and of the artery supplying the heart and other lower members, which I found to be all withered shrunken and desiccated. The other autopsy was on a child of two years, and here I discovered the case to be exactly opposite to that of the old man."
MANY OF LEONARDO'S drawings depict the spiralling motion of water and the forms taken by the fast-flowing water on striking different surfaces. He correctly concluded that a fast-moving river can transport larger particles than a slow-moving river. He discussed the conditions that cause a river to meander. Leonardo believed students of painting must learn about the ways light is reflected and about the importance of water vapour and smoke in the air. One discovery described in the Codex Leicester is that the dimmer secondary light of the crescent moon is the reflection of light from the Earth and its oceans. Leonardo revolutionised painting technique. He was the first painter to omit haloes of scriptural figures, the first to show hands as well as faces of sitters, and his treatment of light in paintings such as the Mona Lisa changed forever the way artists used light in their paintings.
Let me end by quoting Leonardo's description of the penis which illustrates the humanity and the irreverent wit of this pre-eminent Renaissance Man: "It has dealings with human intelligence and sometimes displays an intelligence of its own; where a man may desire it to be stimulated it remains obstinate and follows its own course; and sometimes it moves on its own without permission or any thought by its owner. Whether one is awake or asleep, it does what it pleases; often the man is asleep and it is awake; often the man is awake and it is asleep; or the man would like it to be in action but it refuses; often it desires action and the man forbids it. That is why it seems that this creature often has a life and intelligence separate from that of the man, and it seems that man is wrong to be ashamed of giving it a name or showing it; that which he seeks to cover and hide he ought to expose solemnly like a priest at Mass."
William Reville is associate professor of biochemistry and public awareness of science officer at UCC - understandingscience.ucc.ie