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MOST IMPORTANT SCIENTIFIC DISCOVERIES
Great circle of blood circulation. History and essence of scientific discovery
Directory / The most important scientific discoveries There are truths that today, from the heights of our knowledge, seem completely obvious, and it is even difficult to imagine that there was a time when people did not know them, but, having discovered them, still disputed them. One of these truths - the systemic circulation in living organisms - was born especially painfully and difficultly. During the one and a half thousand years of the domination of the cult of Galen in medicine, obviously the longest and most reactionary cult in the history of science, people believed that arterial and venous blood are different liquids, and if the first "carries movement, heat and life", then the second is called "nourish the organs". Dissenters were intolerant. The Spanish doctor Miguel Servet in his essay devoted several pages to blood circulation: he described the pulmonary circulation discovered by him. In the same year, 1553, the clergy burned him as a "apostate" along with the "heretical" book he had written, and only three copies of it did not fall into the Protestant fire, which incinerated its author in Geneva. Indeed, those who came to the circle of blood circulation have gone through seven circles of hell. There were several of them, these courageous pioneers, to whom people erected monuments: in Madrid - to Miguel Servet, in Bologna - to Carlo Ruini, in Pisa - to Andrea Cesalpino, in England - to William Harvey - the one who put the last point. William Harvey (1578-1657) was born at Folkestone in Kent, the son of a prosperous merchant. The eldest son and chief heir, William gladly changed his "business" first to the narrow bench of Canterbury College, and then for many years voluntarily imprisoned himself under the arches of Cambridge. At the age of twenty, Harvey is drawn to the natural sciences. According to the custom of schoolchildren of that time, William sets off on a five-year journey. First he goes to France, and then to Germany. In 1598 Harvey went to the University of Padua. Here he listens to the lectures of the famous anatomist Fabrizio d'Akvapendente. This scientist discovered special valves in the veins, but did not understand their meaning. For him, they were just a detail of the structure of the veins. But Harvey thought about the role of these valves. He decides to experiment on himself. Tightly bandaging his hand, William saw how the arm below the bandage soon became numb, the veins swelled, and the skin darkened. Harvey's next experiment was on a dog. He tied up both her legs with lace. And again, below the dressings, the legs began to swell, and the veins swell. When a swollen vein in one leg was cut, thick dark blood dripped from the cut. After an incision on the other leg above the dressing, not a single drop of blood flowed out of the cut. It became clear that the vein was filled with blood below the dressing, but there was no blood above the dressing. The answer suggested itself, but Harvey did not jump to conclusions. A cautious researcher, he tested his experiments and observations many times. In 1602, William received his doctorate and settled in London. In 1607 he received a chair at the London College of Physicians, and in 1609 Harvey became a doctor at St. Bartholomew. In 1625, Harvey became an honorary physician at the court of Charles I. He is making an excellent career, but he is more interested in science. Harvey dissects various animals, but most often cats, dogs, calves. The scientist also dissects the corpses of people: the prohibition to open corpses no longer existed. And every time he examined the veins and arteries, cut open the heart, studied the ventricles and atria. Every year, Harvey understood better and better the network of blood vessels, the structure of the heart ceased to be a mystery to him. In 1616, he was offered the chair of anatomy and surgery at the College of Physicians, and the very next year he expounded his views on blood circulation. During the lecture, Harvey first expressed the conviction that the blood in the body is constantly circulating - circulating, and that the heart is the central point of blood circulation. Making a similar conclusion, Harvey refuted Galen's theory that the liver is the center of blood circulation. The riddle of the path of blood in the body has been solved. Harvey outlined the circulatory scheme. But, having told about his discovery at a lecture, he was in no hurry to publish it. William took up new experiments and observations. The scientist, as always, is thorough and unhurried. Only in 1628, when Harvey was already fifty years old, did his Anatomical Study of the Movement of the Heart and Blood in Animals come out, with the work appearing not at home, in England, but in distant Frankfurt. A small book of 72 pages made him immortal. In it, the scientist described in detail the results of thirty years of experiments, observations, autopsies and reflections. Its content strongly contradicted much of what anatomists and doctors strongly believed not only in ancient times, but also in Harvey's contemporaries. Harvey believed that the heart is a powerful muscular bag, divided into several chambers. Acting like a pump, it pumps blood into the vessels (arteries). Tremors of the heart are successive contractions of its departments: atria, ventricles, these are external signs of the work of the "pump". Blood moves in two circles, always returning to the heart. In a large circle, blood moves from the heart to the head, to the surface of the body, to all its organs. In a small circle, blood moves between the heart and lungs. There is no air in the vessels because they are filled with blood. The general path of blood: from the right atrium to the right ventricle, from there to the lungs, from them to the left atrium. This is the pulmonary circulation. The honor of opening the pulmonary circulation belongs to the Spaniard Servetus. Harvey could not know this, because the book of Servetus was burned. From the left ventricle, blood exits in the path of a large circle. First, through large, then through increasingly smaller arteries, it flows to all organs, to the surface of the body. The blood makes its way back to the heart (in the right atrium) through the veins. Both in the heart and in the vessels, blood flows in only one direction. This is because the valves of the heart do not allow reverse flow. Valves in the veins open the way only towards the heart. Harvey, of course, did not know how blood gets from arteries to veins. Without a microscope, the path of blood in the capillaries cannot be traced. Capillaries were discovered by the Italian scientist Malpighi in 1661, that is, four years after Harvey's death. At the same time, Harvey understood that the transition of blood from arteries to veins must be sought where the smallest branches of arteries and veins are located. Harvey did not know the role of the lungs either. In his time, not only did they not have an idea about gas exchange, but the composition of the air was unknown. Harvey only stated that in the lungs the blood cools and changes its composition. The arguments and evidence given in Harvey's book were very convincing. And yet, as soon as the book appeared, Harvey was attacked from all sides. The authority of Galen and other ancient sages was still too great. Among the opponents of Harvey were both prominent scientists and many practitioners. Harvey's views were met with hostility. He was even given the nickname "The Charlatan". One of the first to subject Harvey to derogatory criticism was the "King of Anatomists", the personal physician of Marie de Medici - Riolan. For Riolan - Poi Patin (Moliere avenged him for Harvey, ridiculing him in his "Imaginary Sick"), for Patin - Hoffman, Ceradini - there were much more opponents than pages in his book. "Better Galen's mistakes than Harvey's truths!" was their battle cry. Harvey had to endure many troubles, but then more and more began to be reckoned with his teachings. Young doctors and physiologists followed Harvey, and at the end of his life the scientist waited for the recognition of his discovery. Medicine and physiology have embarked on a new, truly scientific path. Harvey's discovery created a fundamental change in the development of medical science Author: Samin D.K.
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