Vortex Universe Part 2

I think everybody knows of Leonardo da Vinci as the universal man, the typical and the most unsomann interesting, all different subject matter. But I hope the anatomical drawings in the totality of people and understanding that Leonardo was not simply an artist who dabbled in the sciences that his scientific pursuit of somehow as a bizarre or curious scientist, but that his scientific studies were central to his activity and that the anatomical drawings in particular are of such quality and such sustained brilliance in some ways, that the Leonardo deserves to be thought of as one of the great scientists of the Renaissance, at least the equal of his status as a painter. Well, this is one of the largest and most detailed of Leonardo's anatomical drawings. It was compiled around 150-90, essentially as a compilation of all his understanding of the human viscera. Based primarily on the section of a man who claimed to be 100 years old that Leonardo carried out a couple of years before, and you can see several of the elements from the dissection of that centenarian. He probably had cirrhosis of the liver and you see there's an enlarged spleen, the hepatic vessels are unusually prominent and the unbillical vein has opened up due to portal hypertension. The heart is shown with only two chambers. Leonardo's great investigation of the heart where he discovered the atria, it's still to come. The aortic arch is probably bovine, it's too symmetrical for the human, it shows that Leonardo was still reliant as some degree on animal dissection. You can also see that down here in these huge ligaments that extend from the uterus side words which typically bovine rather than human. If you look closely at the uterus, you can see it's got seven chambers which was traditional and passed down from a married stock. Within this one drawing Leonardo is trying to crowd an enormous amount of information, but it's just a staging post on his road to a full understanding of the human form. Throughout his career Leonardo intended to publish his anatomical research as an illustrated treatise on human anatomy, but at his death in 1519 all his anatomical papers remained amongst his private studio possessions and they were essential loss from sight. So Leonardo, whereas he could and should have been one of the great figures in the history of anatomy, is essentially just a footnote. Around 1600 about 600 of Leonardo's surviving drawings were bound together in a single album. And by 69 it was in the Royal Collection, we don't know how it came into the collection, there's no documents, but we think it was during the reign of childhood second. As a great artist Leonardo had two advantages over his contemporary anatomists. First of all, as a sculptor, engineer architect, he had an intuitive understanding of form. When he dissected the body he could understand and never in a very fluid way how the different parts of the body fit together, how they work together. And then having made that understanding as a supreme draftsman, he was able to record his observations and discover his in drawings of such lucidity. He's able to get across the form, the structure to the viewer in a way which had never been number four, but in many cases has never been surpassed since. This is one of the sheets of studies resulting from a campaign of dissection that Leonardo carried out in the winter of 1510. Probably the University of Pavea just to the south of Milan, where he is reported as having collaborated with a young professor of anatomy there, Mark Antonio del Torre, and the results can be seen on a page such as this, which is dense with detail. His studies, the muscles of the shoulder and arm, the structure of the hand, and you see the nerves and the arteries feeding into the hand. And here at the centre of the sheet, an amazingly sophisticated dissection of the muscles of the face. This is very, very difficult to dissect and Leonardo has got it almost perfectly correct. They can identify every single muscle. Now, the drawings are surrounded by this patchwork of notes. In these, his partly explaining the drawings on the page, but also setting himself further topics that he wanted to investigate. Their sheets done for Leonardo's own record. They're not intended for anybody else to see and consequently he wrote in my image with a left hand for right to left with every word and letter in perfect marriage throughout his life. It was simply easier for him, I think, as a left hander. If you turn the sheet over, because this is a sheet from a note book, and Leonardo compiled drawings and notes on both sides, you can see Leonardo's most comprehensive study of the skeleton. He's treated it on the Slicanar architectural drawing with three elevations, mutually orthogonal angles, from the front, from the back, from the side. Leonardo's last and in many ways his finest campaign of anatomical investigation was into the structure of the heart. Working mainly with an ox's heart, he dissected it to an extraordinary final level of detail and the sheet of studies you see here is an investigation of the functioning of the aortic valve. Leonardo realized that the root of the aorta was a slight swelling, a lot of chamber which we now call the sinus of Valcellova, and he wanted to investigate the function of this. So he injected molten wax into the aorta and it certainly could see this bulb shape when he dissected it away. Then he made a glass model around that wax cast and he shows it in cross section here. Then he could pump water with a suspension of grass seeds through his glass model and observe these vortices in the sinus immediately above the aortic valve. And he deduced that these vortices played a crucial role in the opening out of the cusp of the valve after each pump of the heart. And it's absolutely right. It's only in the 20th century that cardiologists agreed with Leonardo that the vortices in the sinus of Alcellova are crucial for the function of the aorta. It's the most incredibly sophisticated piece of investigation and shows Leonardo as an experimental scientist at the upper edge. Absolutely best.