Relationship of fine art and medicine, December 3, 1992

Moderator: With this, which is the first college of medicine lecture of this year's series. I'm very delighted to introduce to you Dr. Francis Robicsek. Dr. Robicsek, wears on occasions one of several hats. He is at sometimes the director of Carolina's Heart Institute in Charlotte, and it's training program of thoracic surgery. He is also a president of the Heineman Research Center there. And then when he's not wearing one of those hats, he's director of the Sanger Clinic in Charlotte, North Carolina. He is known to those of us in surgery as a very highly respected clinical cardiac surgeon, and particularly recognized as an innovator, and investigator in many areas of surgery, not just cardiovascular. His medical curriculum vitae now contains more than 400 entries. Unlike most of us, however, he also has a second curriculum vitae concerning his publications in the art world. As he is regarded as one of the world's experts on Mayan art in particular. Having heard Dr Robicsek lecture several years ago at our own art museum, I know that you will all find his remarks very interesting, and his insights very fascinating regarding the relationships of fine arts and medicine. Dr. Robiscek. Dr. Francis Robicsek: Dr. Barrond, Dr. Sopra, Dr. Earnheart, ladies and gentlemen, the pleasure of being here is literally mine. I had the honor of visiting your institutions about 15 years ago if I'm correct, and the changes which occurred is amazing. Fortunately, one thing didn't change, the presence of good friends, and it's always a special occasion for me to come back. May I have the first slide, please. Today, my talk will be really centered the contribution of Leonardo Da Vinci, on the human body. And you know, when you talk of Leonardo Da Vinci, Michelangelo, Raphaello, you know it's ... what can you say? They were great artists, nobody debates it, and if you want to know about them, buy an art book, or what. But I started off on Leonardo and what you get out of the little what we know of the man, it literally blows your mind. So let me go a little bit into that method. Do you hear me now? Yeah. The most recent contribution in modern cardiology, yeah, the most recent contribution in modern cardiology is that we are recognizing that the ... can we turn the lights off maybe? We are recognizing that some anatomical structures the aortic vale, what we thought before is nothing but a flipping little leaflet. Entirely passive, responding to the blood pressure, is really a very mobile, very live, very functional organ. The annulus of the aortic valve is changing, the size of the leaflet is changing, the closure of the leaflet is changing just from one heart cycle to the other. This, for instance, shows you the appearance of the human aortic valve under different kind of pressure. You see, the size of the aortic valve changes tremendously, but the thing that puzzled the anatomist, and the clinicians the most are the presence of the sinus of the Valsalva, there are two bulges on the side of aortic valve. Here is the valve, and here are the sinuses. And none of us knew what the sinuses of Valsalva are for. In the last five, six years, there are some very interesting studies which show that when the heart ejects the blood during systole, and the blood goes out through the periphery, some blood turns around in the sinus of the Valsalva, which shows one aortic leaflet, and starts pushing on aortic leaf just like you close your hands together. And then the diastole occurs the aortic leaflets are practically enclosed at approximation. That's why you don't have massive aortic regurgitation with every heart contraction. This shows some hemodynamics experiments, in vitro, the dye is injected in this tube which represents the east end of the aorta. And most of the dye goes out, but some of them curls back, starts pushing on the valve, and the valve starts closing while the heart is ejecting. This is a very interesting new phenomenon, which really excites the cardiologists and physiologists very well. This is how it begins, here, it starts pushing the valves closure, and the valve is just about to close before the heart ejection occur. And this is also one of nature's very wonderful invention and before we didn't know it, now we do. However, if somebody looks a little bit backward, Leonardo Da Vinci, the renaissance painter, scientist, sculpture, inventor, whatever you call it, Leonardo Da Vinci knew it. He knew it around 1495 plus. And investigating this particular aspect of hemodynamics, I stumbled across Leonardo's finding, and after I went through part of them, I really just couldn't stop. Leonardo Da Vinci, as most of you know, was born in Tuscana in the village of Da Vinci. That is his house of birth. It's marked properly as his birth place. As a young apprentice he worked in the workshop of Verrocchio, this is Verrocchio's David. And according to legend, Verrocchio modeled it after Leonardo Da Vinci, who was a very handsome, very powerful, and very good-looking young man. This is the only picture I could get of Donatello, and [inaudible 00:06:41] also. Accommodated with ... and it soon became apparent that Leonardo Da Vinci was not just the usual apprentice. This is supposed to be one of his first major work. He painted the angel of one of the major paintings of Verrocchio, and Verrocchio looked at the work and he said "He's better than I am." And it went on. He lived in the first part of his life in the renaissance Florence, which was led by the Medici's, and here you see one of the contemporary paintings with the Medici clan leading the Florentine mobility. Here is Lorenzo the Magnificent leading the procession. Here is Giuliano Medici and, again, this is a young painting of Lorenzo the Magnificent. This was Giuliano Medici who was assassinated in the power struggle of Venice. And this is one of Leonardo's early drawing, who drew the murderer who was caught and hung, and he made a sketch of it and maybe, just maybe he was the first corpse he could put his hand on it, and did the dissection to study the human anatomy. Leonardo was well known as a painter, and probably the best or nearly the best, if he was anything like this. This is the Madonna of the Rocks, this is the detail of the annunciation. This is another detail, the angel reports then the rabid test was positive or whatever. This is the Benois Madonna of Leonardo Da Vinci. This is St. Veronica and the Madonna, and a series of beautiful Madonna's of the tribe, and other scenes from the bible. That is a noble lady from Florence. This is the Lady with the Ermine. She was the mistress of one of the Sforza's in Milan, and she and Leonardo didn't like each other too much, but he had to paint her portrait so he got even with her of putting this ermine, and they say that the expression of the ermine and the lady was very closely resembling. This is Genevra, and he put little puzzles in it, in the background you see the [inaudible 00:09:12] bush. This is Leda and the Swan, mythological picture. I still don't know how the swan did it, but must have done it somehow. This is another Madonna of Leonardo, and so on. This is one of his last painting, this gentleman is not giving the finger to anybody, he's Saint John, and holds really the staff. If he's had done, this is naturally Mona Lisa Gioconda, as all you know, and this is Mona Lisa's cat. The thing that interested me most, however, is Leonardo's notebooks. And it contained many pages, most some of them are lost, but a good portion was saved and right now in the present time is in the Windsor Castle, in the collection of her Majesty Elizabeth. Now if you think I did the slide in reverse, no, because Leonardo wrote left handed, backward, and you could read his writing only from the mirror. He didn't want anybody to read his notebook, and he was very secretive. And he did a lot of sketches of machines, inventions. And besides this safety measure, if you tried to build anything Leonardo designed, it doesn't work. Because every design has a deliberate fault in it. Just a screw put in reverse, or whatever. So that reflects on him a little bit. This is another page of Leonardo's notebook, and it really blows your mind. There is this, and that, and this, and pictures, and designs for a school, and artworks. So, it's really a collection of a man who was thinking 24 hours a day. Most of the things he could not finish, there was nobody who discussed it with. It was literally a genius in seclusion and alone. Any sketchbook we find many different subjects. Some of the pictures, like this Isabella D'este, or the sketch for a painting. This is a sketch from St. Veronica and the Virgin. This is also a preliminary sketch for one of his paintings. So they really served as a sketchbook, notebook, for his paintings. This is a detail of a hand, a beautiful folding robe. So that's what you would expect in the notebook of the painting of a painter. Other sketches shows costumes for a costume party of the Sforza's. This is his design of a military uniform, and this is again a court costume design. Apparently, he did these in order for the Medici's, and later on for the Sforza's. He was also a very noble known architect. He designed church, and he started to work on design of fortification in the very early of his life. Later on, he moved from Florence back to Milan, then from Milan he came back later and again to Florence. And in Milan, his patron was the Lord of Milan for Sforza, who was called Moor because his features bared a little bit resembling Negroite and he was called a Moor for the Sforza castle in Milan, who stands today as it stood at that time. And he was first employed by an architect to the court of the Sforza's. He designed not only buildings, but he was a very well known city designer, this is not Milan, but an adjoining little city. And he worked on palaces, and that was Leonardo the architect. He also designed apartment houses of multistory, apartment houses. He designed bordellos, he designed stables, he designed everything that you can think of it. This is again, a villa he designed in Florence. And here there, you see the artist popping up in the corner of an architectural drawing. You see a design of a sculpture, and so on. Here again you see the human body super imposed [inaudible 00:13:37] architectural drawing. He worked for the Sforza's and designer of canals. The canals which are in existence today in Milan, significant portion of it was designed by Leonardo. He was officially named as supervisor of the canals, and at the time he became probably close acquaintance with fluids, with the water. A lot of his sketches reveal water streams. Here, he was studying amid models, how different objects, things that flow with water, how water came out of the faucets, waterfalls, and so on. Again, also, his notebooks. Water everywhere. He designed, also, locks. Use the principle of communicating vessels and made all kinds of levers and pulleys. This is the water lock design by Leonardo, and he installed it on one of the canals in Milan, which is an ingenious device. It is slanted, the water pressure keeps it closed, and when you want to open it up, you open it up a little lock so the water fills up the other chamber, and then the water pressure opens the door. And they used it a lot in the canals to all over the passenger barges. This is the close up on this water lock again, it is slanted so when this little door is closed, the water pressure keeps it closed but when you let the water in through this hole, the water gradual fills it up and opens up the door. And at the time it was considered one of the leading inventions. And if you work on locks, you also need boats, dredgers to dredge the canals, and this is Leonardo's design of a canal dredger. He also designed barges. And some of them are reproduced in the Leonardo museum in Avignon. And here you see Leonardo's design up in a model. Leonardo was also the one who designed the method how you can lift up sunken boats. Nearly put on containers, and pump air in it, and lift the boat out from under water. And at the same time, however, the artistic activity of Leonardo did not cease. Also in Milan, or wherever you want to get painting, this is his St. Jerome, this is the sketch of ... another sketch of the Virgin and St. Veronica. This is the Madonna and the Magi. And this is some of the swords of palace frescos, where they attribute partially to Leonardo. One of these great work he was working on when Sforza ordered an equestrian statue of his father, and he indeed made not only the sketches, but a huge model which was considered the largest sculpture of this time. But when the French occupied Milan, they shot the model to pieces, and he never started to work on it again. Naturally, you will all recognize the Last Supper, which is in Milan. And I think I saw several representations of the Last Supper, what I could not figure it out why all the apostles sat on one side of the table crowded, and none of them ever sat on this side, but ... I haven't worked on that yet. He had additional paintings, additional portraits, and went back to Venice but then he had to flee because of the appearance of Savonarola, the monk who was anti-medici, anti-art, anti-beauty. So he took off and went to northern Italy, was in the service of the Pope, and then in the Pope Borgia son, Cesare Borgia, who was beside his infamous political activity, very well known and very able commander of the people army. And Leonardo side up at that time as the army engineer for the Borgia's. He participated actively as a commander rank in the Borgia's campaign. And first they used his ability to design forts. This is one of Leonardo's drawing of a moat, in the corner of a castle. And then he got in to arms deeper and deeper. Here is another design of a castle with fortification by Leonardo. Same thing. And he started to work on different military devices. This is a device where you can move close to the wall and be protected from different missiles and mound the walls. Then he thought "If they can't do it, maybe I can do the opposite as well." This is also design of Leonardo, this is the enemy on this side try to go through the wall by letters, and they are just waiting for it to push this aside, and push them all down. This is the design of him, how to detect when the enemy tries to dig a ditch under the walls of Leonardo's drum. The little balls started to tremble whenever they are digging under the wall. He designed a very modern military bridge, which is portable for the Sforza's. Which is mobile, and can be moved to any stream, or river, or whatever. And this is the model of the bridge as it is today in the [inaudible 00:19:43] museum. And it's perfectly modern, and absolutely functional. And then on the veteran's he started on the very simple, and the very classic. This shows one of his warriors, which has not only one lads, but several mounted on this horse. And he designed this battlewagons with slice on the side, which cut the enemy to pieces. And this is a boat ... this somehow doesn't work for me here. It's ... this is a boat which looks very peaceful, but under the water it has this thing sticking out of it to poke holes in the bottom of the enemy boat. This is the catapult designed by Leonardo, and there's a huge bow which could hurl tremendous size arrows at the enemy. Then he got a little bit more modern. And just on the side, he designed the first workable flint rock rifle, which was done by Leonardo. And then he got involved in projectile and bombardment. Those are mortars well known by Leonardo's time. And he studied how the projectiles go from one place to the other, and at the same time invented the shrapnel ... a projectile which explodes on contact, and blows the enemy up, and for some mysterious reason [inaudible 00:21:13] about the shrapnel at the same time. That is Leonardo's design of placing mortars on the fortification, and deliver a mirage of file, which makes the enemy impossible to come any closer, very modern. This is Leonardo's design of a canon. And this shows a sketch of the forts that he was building canons for the Sforza's and/or the Borgia's, nobody knows. And this shows Leonardo's breech-loading canon, which is as far as we can tell, was the first one in military history. It's this pointer here. Alright, that is much better. This is a platform but Leonardo deigned, which had several mortars mounted. And after one was fired, this was turned and the next mortar was ready to go. And this was Leonardo's machine gun. And if this is not a gatling gun, I don't know what it is. But with that he was able to fire for a long time. This is another model of the same. Nobody knows if he really built it or not, but in the [inaudible 00:22:29] museum there is a model which is in the workable, and could be used today. This is another gatling gun model from Leonardo. Again, the model is one that looks quite well, and this shows a rolling gatling gun model, just like it was used in the U.S. Army, which was able to fire as far as I counted 32 [inaudible 00:22:57]. And if you don't know what is this thing, it is called the Turtle. this is the first tank designed ever in military history. It had wheels, and there were guns mounted on both sides. And this is the model in the Avignon museum. There were metal plate, and it was a perfectly functional metal bagger. This is a modern shell bullet, rifle bullet, designed by Leonardo. And then this is an absolutely modern aerial bomb from Leonardo's notebook. To think really blows your mind. This is a wheel what he designed for cops, which assured. And this is a, now how do you call it, ball bearing which appeared first in any mechanical drawing in Leonardo's notebook. And this is another ball bearing, some that are more modern variety, and this is again the model in the Leonardo museum. This is a modified archit made screw to hoist heavy weights, and this is a fly wheel, what he used as a water powered device. And this is built the model, and you wonder "What the hell was an artist who painted the Mona Lisa doing with this wheel?" I have a very interesting experience, I am going to come back to it. This is a steam engine built by Leonardo. This is a chain wheel, just like a bicycle chain, isn't it? But what for? And one of this chains that you find quite a modern bicycle designed for Leonardo. This is a little close up, and this is the bicycle chain. And this is his sketches, how to make this chain. And if you take a look at your own bicycle, you'll find exactly the same. Again, different mechanical devices to hoist weight. It is a textile machine which could work today. This is a water wheel which gets water up on the top of tower. Where there is another machine puts it up in water tower to supply the city with water. This is, again, a water wheel to raise water for irrigation. And if you're wondering what the artist was doing right at the present time, there is a painter exhibit in the Los Angeles museum by a modern artist called Tensi. And he made this painting of Leonardo's wheel. And he said "Leonardo's mechanical experiments for controlling water, and natural forces suggest that we as a metaphor of mediation between tranquility and turbulence." I don't know exactly what he means, it's a beautiful painting and somehow Leonardo's spirit, anyway, got to him. That was Leonardo's principle scene was. Without science, art is nothing. The other favorite thing was God [inaudible 00:26:29]. From the mechanical devices, he went to the study of nature. This is one of the beautiful sketches of a Medusa, and then a Lily. Then he made the design for the Colossel's. The equestrian statue of Sforza's father. And he had another painting The Battle of Anghiari, it did not survive, this is a copy of Reubens he made of Leonardo's paintings. He studied horses from all angle, from all view. He studied pussy cats, he was very interested in everything around him. He studied nature, and finally, ended up with a human body. Now, during Leonardo's time, human anatomy was very, very primitive. This shows an advanced study of human anatomy. There is a dissector, a professor who would not touch the human body, and there are the students looking at it from a respectful distance. Here you see the same scene, the professor on the cathedral, lonely attendance during the dissection, and the students in the background. And they usually has maybe one or two autopsies a year, on a famous university, not more. This was a result was that on a human body was portrayed in textbooks, or like this, showing the different types of injuries the human body sustained. That was not enough for Leonardo. He started off sketching people, making studies, caricatures, for his own passion, or for things you don't know. This is the painting what this is the sketch what we showed at the beginning where he's working on the geometrical symmetry, and the regular human body. Everywhere he made sketches, he looked for geometry. Triangles, right angles. Here you see again one of his sketches of the human face. The proportion. Regular face. But he didn't stop there, he went a little deeper. He went and studied the skull which was under it from all aspects, and all these pictures would fit very well in a modern anatomy book today. Just like any other painters, he paid extreme attention to the human body. To the skin, to the muscle. But while the rest of them, Michelangelo, Raphaello, stopped at this level, even deeper he studied human emotion. And he also looked at it, what made the human emotion possible? He went onto the muscles, he went on to the tendons, he studied the vessels, and if you look at the study of the veins it really reminds you of the Vesalius picture I'm going to show later on about the perfect anatomy, and the absolute acute and astute observation. Here he studied on the tracheal, here you see a diverticulum on the seam right next to the muscle and the tendons. This is his study of the nerves of the back and the neck, how they innervate the muscle with them. He was the first one to recognize the physiological curvature of the spine, and he was the first anatomist to show the correct number of vertebres. Here it is again, another study, showing which today could go into any anatomy book. He was the first one to give a lot, and use topographical anatomy in cross-section rather than in longitude section. Here is another showing the same, the study of the lower extremity in cross-section. Leonardo was the first. He studied the motion of the leg, and he also developed a comparative anatomy. Let me go back one. Now it is stuck, well I will just go forward. And this is the foot of a bear which he compared to the human foot and made observation how we are similar or different, from the animal. This is the study of the shoulder, here's a perfect rendering of the shoulder joint and how the arm moved. And he did not stop either, he wanted to know how did this thing work. So he got the boney arm of the skeleton, put on wires, and studied what kind of a weight, and what kind of a force is needed to use, to move the human extremities and make them work. In his comparative studies, he got fascinated with birds. He made observations how the birds fly, how they move the wing, how they float in the air. Is another study in his notebook of the same. And studied the air currents. Now this is from Leonardo's notebook showing how he showed the currents of the air over the wings of the bird. And this is a modern study of the wings of a Cormorant showing exactly the same. He studied the wings of the bird, how the bones were attached, how the thing worked, and then he tried to duplicate it. And then he made the design of his flying machine. This shows Leonardo's airplanes wings, what he made at first. Absolutely today imitation of the bird wing. This shows one of the wings completed, and this is the fuselage, man's supposed to lie in there, and move the wings, and flap it like the bird with his muscle. That was indeed built, and one of his students prematurely then topped to the city wall and tried to fly, and he was not very successful, and crashed, and Leonardo stopped building his airplane at that time. Again, in the nature he observed a dragonfly, how the dragonfly flew, and I said "Maybe I could build a helicopter." While he didn't build it, he certainly designed one, which is very, very close to helicopter. Then he thought "Maybe that wouldn't fly," he got another model design of a helicopter. And they built model of that and Leonardo's drawing not knowing the gasoline engine, this was turned by a human, the modern machine, with a gasoline motor was flying. He studied respiration. He studied the angle how the breast, the thoracic cage move in inspiration and expiration. Now, don't forget we are talking of hundred years before Harvey. And there was nothing before him, and for a long while there was very little after him. Again, this is his study of the function of the ribs. And he made a stout observation how the air moved in and out. And he tried to make it somehow that the observation worked in the practical life. This is a boy, and this is a diver, and he designed this device how you can go underwater, just walk around and keep breathing with the tube attached to the boy. And this is the life belt which was designed by Leonardo, and also the flippers what the diver can put on his feet or hand, which helps him to move around. This is a water ski, I mean, what you can do with the ski design. This device which contained air and was appropriate device that somebody could walk on water. This is Leonardo's parachute, and he indeed was tried one of his disciples jumped from a high tower and landed safely. And this is the model of the parachute in the Leonardo's museum, very functional. He was fascinated with the sight, with the sound, with the taste. This is his study of the echo, and he could measure the speed of the sound by doing his studied on echos. This is a flute, what he designed, he tried to imitate the human voice box, and was studying the pitch of the sound. This is a mechanical drum, what he designed somebody just had to turn it, and they drum nicely. He was particularly interested in the human eye, and optics. This is his study of the human eye. But again, he didn't stop there. He cut it in dissection, he described the optic nerve, and the center of vision. Here are all his studies of the inner vision of the eye, and even to optics, and he knew exactly how the light finds and goes through the pupil, and gets on the back side of the arm. He has about 15 pages for human optics. He was interested in every function of the human body. This is his known, or notorious drawing of the human intercourse. Here's the male organ penetrating the female organ. And he was the one who described the villi of the placenta, and he described the placental circulation. First time in anatomy, he knew it. He's the first one who showed the fetus in the fetal position. Has not known before Leonardo, he had one occasion to perform an autopsy on a pregnant woman. But his most interesting area was the circulation. And this is one of the early drawings shown somewhat of an artistic background. And again, when you look at it, we are talking a hundred years before Harvey. Leonardo thought that the blood goes from the heart out to the periphery, stays there and never comes back. And if a people [inaudible 00:37:14] would not have interrupted his anatomical studies in his later part of his life, he was forbidden to do anymore dissections, it would have been Leonardo, and not Harvey, who had discovered the circulation of the blood. He's initial drawings are very, very primitive, but as he pass, he's drawing could fit into an anatomy book very easily. This was a gentleman who stopped doing it. This is the description of Leonardo of the heart. It was, I believe, the heart of an ox and not a human. The coronary artery, the aortic valve, the backside of the heart, that is Leonardo's rendering of the bronchial circulation. Which has never been shown before. This is the human heart, and the bronchial arteries coming from aorta and loin, along the bronchi. Leonardo was the first to recognize the atria as functional part of the heart, he showed the musculature on it. Until Leonardo, the atria were regarded as just an extension of the vagal vein. He was the first one who believed that they are pumping chambers, just like the distal portion of the heart. He described the moderator of the band in the right ventricle which is known today as the band of Leonardo. That is Leonardo the architect, designing arches. This is Leonardo the aquatic engineer designing ducts. This is Leonardo designing the arches again in buildings. And this is Leonardo who worked on the mitral valve recognized the same function, the same beauty, what he saw in architecture. This are the papillary muscle, and you can really superimpose it on the archer of that palace he drew two pages before. This is the approximation of the mitral valve leaflets, they are perfect anatomical drawings. Those are, again, showing the papillary muscles. The function and approximation of the semi lunar valve from an engineering view point. And this is very interesting ... in Italy, their favorite way to kill pigs is through stick a stiletto in the pigs. And the pigs doesn't like it, but it doesn't die immediately. And Leonardo went to the butcher shop and watched the pigs slaughtered, and he observed how the handle of the dagger moves with the heart. He described not only the heart beat is simultaneous with the pulse, thus the pulse is caused by the heart contraction, but he also made the design and proved that the heart does not only contract but twist around this axis. And just simply by looking at the dying pigs, with stick, with a heart sticking out of his heart. Again, this is one of his last drawing of the aortic valve, and it is very, very similar of what you have seen at the beginning of my presentation in the size. And Right next to the aortic valve there is a design for a portable steam bath. The guy was unbelievable what he was doing. And again, here is the geometry of the aortic valve, to approximation of the mitral leaflets, the streaming of blood in different part of the body, and this is the page which really you have to stop and looking at it, and looking at it, and looking at it. What you see? What that man did, is he poured wax in a heart of an oxen and got an imprint and a model from the inside. How the left ventricle [inaudible 00:41:19] looks. And get a glass blower, and made a model of the left ventricle or [inaudible 00:41:26]. Then, he pumped water through it, and then he took out the heart of the pig, this is the first bioprosthetic valve, mounted it in this glass model, and presented the first parts duplicator. Then he said "I like to know how the blood flows through it," and sprinkled fine seeds of grass into the water, and found that when the fluid is pumped through this model of the left ventricle, it forms curls in the sinus of the valsalva, and his conclusion was probably this assures the perfect closure of the aortic valve. And then, when he decided that he said "This aortic valve is a very simple thing. Structure I can design one," and he designed, but never made the first bioprosthetic valve. Right now we are working on a new aortic graft, which incorporates the sinus of the valsalva, built on Leonardo's principle. Vesalius came about 40 years after Leonardo, who discovered and wrote down the newly circulation of the blood in the veins. And Harvey came 50 years later. Leonardo died in France, this is the house given to him by the French, King Francis. And this is the city of Avignon, and if you close ... a little city close to Avignon, and you really should go by there if you can. This is the last self portrait of himself, of Leonardo. And could you turn it upside down, I'm doing same what he did with his notebook. This is not deliberate. Once more. Went through 342 slide just to stumble on the last one. Great. This is from his notebook. "In spite of your love or such investigations, you may be deterred by the repugnance if not, then by the fear of spending the night in the company of corpses, that are cut up and flayed and horrible to look upon. And if this does not deter you, then perhaps you like the skill in drawing necessary for such representations, and if you can draw, you may have no knowledge of the perspective if you have it. You may not be versed in geometrical exposition, only the method of calculating the forces and energy of the muscles, or perhaps you are lacking in patience so you will not be diligent. Whether or not I possess all this qualities, you'll be attested 120 books whose composition was delayed not by negligence, but time alone." Clap now. Thank you.