Sunday, 6 July 2014

Leonardo: Drawing the heart strings

When you're spending time on a dissertation as fabulous as mine, it takes a very special lecture to distract you. One such lecture turned up and I needed to go! I attended the second John Hunter lecture last year and this year's joint venture organised by the Huntarian Society and the Royal Society of Medicine looked fascinating.

Mr Francis Wells presented 'The heart of Leonardo seen through contemporary eyes' and as the notes said, his 'interest in the Arts is a long-standing in both music and art, particularly in the areas of the Renaissance and the act of drawing. The accuracy and beauty of the drawings of Leonardo da Vinci are of particular interest and fascination'. He has collaborated with Martin Kemp, and last year he worked with Windsor Great Library on an exhibition of the heart drawings for the Queen's Gallery. He has since published 'The Heart of Leonardo', which is presumably from where he drew most of the lecture notes. As he also works as a consultant in the fields of heart valve reconstruction and heart and lung transplantation, the scope of his knowledge and expertise is awe-inspiring.

He was recognised for a Hunter Professorship by the Royal College of Surgeons, so his link with the Huntarian Society has been long established, making him an excellent choice for this third Huntarian Lecture. To emphasise the connection with the famous surgeon, anatomist and pathologist, he offered a short introduction to both Hunter and Leonardo (1452 -1519) and their interest in the art of looking.

Hunter advocated the scientific method and wanted to challenge and test everything. He discovered the heart drawings in 1754 and was instrumental in getting them out into the wider world. Wells then offered a raft of quotations supporting the importance of drawing in learning to look and see, and developing an artistic eye and scientific mind. Most beautifully from Edvard Munch, 'nature is not only all that is visible to the eye... it also includes the inner pictures of the soul. Vasari in his 'Lives', said of Leonardo,

It is clear that Leonardo, through his comprehension of art, began many things and never finished one of them, since it seemed to him that the hand was not able to attain to the perfection of art in carrying out the things which he imagined; for the reason that he conceived in idea difficulties so subtle and so marvellous, that they could never be expressed by the hands, be they ever so excellent. And so many were his caprices, that, philosophizing of natural things, he set himself to seek out the properties of herbs, going on even to observe the motions of the heavens, the path of the moon, and the courses of the sun.

Raphael (1483 – 1520) held him in such high esteem that he was used as a model for Plato and placed at the centre of the School of Athens Raphael. 

Wells suggested that his unconventional educational background was the source of his independent thinking. As an illegitimate child he was not allowed to be classically educated, so instead he made is own way, 'reading by the light of experience'. For instance the dissections of Leonardo's time were still using Galen as a guide, with men such as reader, prosector, demonstrator,all blindly following and ignoring discrepancies in the text and cadaver. Not until Versalius (1514-1564) did the illustrator actually do their own dissection and start getting it accurate.

He then broke off to tell us a story about some of his own dirty goings on. He was asked as a heart specialist to join a group of people who were making a film about dissection. As candles were lit on set in an abandoned church, and people were rather bloodied, there was a wail of police sirens. Someone had reported the suspicious behaviour. After they had spent a couple of hours at the police station assuring them that they had appropriate permissions and weren't dark magic practitioners, they were allowed to return to filming.

Still, he said that it offered a small insight into the detail of contemporary inconveniences. The sitting up through the night, when it was cooler. The dark, the smell whilst trying to write and draw. He pointed out that you had to be committed to this noxious habit. Whilst Leonardo was working in Rome, he was berated by pope Julius II. However this pope was not known for his peace loving Christianity, and Leonardo retorted by saying it was worse to take the life of a man.

He related the story of the Leonardo, the pope and the mirror maker. Whilst Leonardo was living at the Belvedere with a mirror maker, he thought that he could do better and started making mirrors too. Anyway this upset the mirror man and he reported Leonardo's dissections to the pope. After a small row, he departed for France. As Wells says, there has to be a treasure trove of material waiting to be discovered in the Vatican.

As Leonardo's investigations progressed he became increasingly more observational and took more information from life (or death...). Wells showed us a 1482 workshop drawing which would have been used for bloodletting and it puts the liver at the centre of blood circulation. This was a demonstration of Galenic ideas where the vessels grew from the liver. It was pointed out by the medical expert that the only time that this happens in the human body is in utero. Leonardo noted on his drawing that the heart needed more investigation. He then compared Hunter's image of a child in the womb with Leonardo's, saying that Hunter referenced the earlier drawing. However he did not place the fetus in an animal womb, which is what Leonardo did.

But it was the heart that appeared to particularly fire his interest, from 1507 onwards, when he had reached his 50s. In those drawings, he used his knowledge of fluids, weights, levers and engineering to try to understand how the heart functions. He also looked closely at the actions of the heart valves and the flow of blood through them. In his 'Anatomy of an old man', when he dissected the heart of a 100-year-old man who had recently died, he produced the first known description of coronary artery disease. He also noted in some diagrams atrial septal defects in the specimens.

Wells then made the good point that these drawings require medical knowledge to be understood, so as a result, art historians haven't made full use of them. The best way to test these images but to actually compare them with the real thing, which is precisely what he has done, and proven them to be works of observational genius. He has discovered that although some human heart diagrams are shown, many were ox hearts. It wasn't just the quality of drawing but the innovative ways of depicting complicated processes, so he deploys exploded images and 'cut outs' to make sense of what he saw.

Not only that but he connects engineering processes with the body, for instance, a little man with elastic band demonstrates the stretching mitral band. Further he uses water ways to show what happens in the heart, especially the valves, which is extremely hard to to illustrate with using a lot of maths. A 1968 article from Nature on vortex formation references just one document but contains 12 pages of working out;

Mechanism of Closure of the Aortic Valve
Department of Engineering Science, University of Oxford.
THE human aortic valve consists of three cusps made of relatively inelastic, muscle-free material about 0.15 mm thick. It opens and shuts about once a second, and withstands a pressure difference of 100 mm of mercury when closed. It usually functions for 70 yr without failure, and works so efficiently that very little blood is regurgitated at each pulse. In order to support this large pressure difference, the cusps must close simultaneously in all operating conditions and should not touch the wall of the aorta, for considerable reversed flow would then be required to close the valve. This action suggests a fluid dynamic control mechanism which positions the cusps away from the wall of the aorta, so that the slightest reversed flow will close the valve.
1. Keele, K. D. , Leonardo da Vinci on Movement of the Heart and Blood, 81 (Harvey and Blythe, Ltd., London, 1952).

He stressed that he was not suggesting that Leonardo discovered how blood circulated. Indeed, Realdo Colombo made several important advances in anatomy, including the discovery of the pulmonary circuit which paved the way for William Harvey's discovery of circulation years later. But Leonardo was close. Much later, Harvey was travelling with the Duke of Arundel and saw Leonardo's pictures. Was he inspired by what he saw?

Wells left us with Leonardo's recommendation to stay away from physicians. 

He finished by reminding us that ultimately Leonardo had limited influence on the history of medicine because of his failure to publish his notebooks.

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