Apr 30, 2013

Medicine -- during 16th, 17th, and 18th Centuries

In the 16th century, as religious prohibitions against human dissection were lifted, the modern study of anatomy began, allowing scientist to distinguish between abnormal and normal anatomical features. Andreas Vesalius, a Belgian physician, dissected human and animal cadavers and proved that the structure of human anatomy differs markedly from that of animals; his discoveries were published in On the Structure of the Human Body (1543), the first work to accurately illustrate human anatomy. Soon after, Gabriele Falloppio described the tubes between the ovary and the uterus, subsequently named for him, as well as previously unknown structures in the skull and inner ear. Bartolomeo Eustachio (1513-74) identified the tube that connects the middle ear to the back of the throat, today known as the Eustachian tube. Hieronymus Fabricius compared the anatomy of embryos of dogs, cats, horses, and humans, and he provided detailed descriptions of the semilunar valves in blood veins. His work was the basis for the discovery of blood circulation by his student William Harvey, who published his findings in 1628 in An Anatomical Study of the Motion of the Heart and of the Blood in Animals, proving, for the first time, that the heart pumps blood into arteries, the arteries carry the blood throughout the body, and the veins return the blood to the heart.

This new understanding of human anatomy allowed surgery to emerge as a separate discipline. Previously, surgery was performed by barber-surgeons and was considered a less dignified occupation than medicine. This perspective was changed by Ambroise Pare, a leading surgeon in the 16th century, who served four kings and earned the reputation as the "father of modem surgery." Using the experience he gained on the battlefield, Para pioneered the use of ligatures and dressings to stop bleeding instead of the painful practice of cautery. Para is credited with originating the use of prostheses - artificial replacements for a missing part of the body - and popularized the use of the truss for treating hernias, which were previously often "cured" by castration.

One of the most important medical tools, helping physicians understand anatomy and identify signs of disease, was the compound microscope, invented in 1590 by Zacharius Janssen, a Dutch optician. Using single-lens microscopes he made himself, Antoni van Leeuwenhoek (1632-1723) later became the first person to see blood capillaries, cells, sperm, and one-celled organisms.

Understanding normal anatomy led to the scientific study of diseased organs. An interest in the causes of disease (epidemiology) became more urgent in this period because of the epidemics of plague and other diseases that were killing huge numbers of Europeans. Paracelsus (1493-1541), a German-Swiss physician and alchemist, attacked the widely held belief, handed down from ancient Greece that disease results from internal disturbances of four bodily "humors" (blood, phlegm, yellow bile, and black bide), stating that external agents caused disease. In the mid-16th century, Girolamo Fracastoro proposed that epidemic diseases are spread by tiny particles, with contagion occurring by either direct contact, indirect contact via infected items, or even without contact.

People with a technical bent looked for ways to detect organ abnormalities in living patients. Traditionally, physicians mainly used a collection of basic tools -scalpels, forceps, and cathetersb-to deal withbpatients. In the 1620s, the Paduan scholar Santorio Santorio developedbthe pulsilogium, originally conceived by Galileo, to measure the beats ofba man's pulse. In 1761, Leopold Auenbmgger introduced percussion – tapping on a patient's chest and listening to the resulting sounds - as a way of determining if the lungs were filled with fluid. New medical practices also emerged during the 18th century. Dominique Amel invented the fine-point syringe. James Lind discovered that ingesting lemon juice could prevent and cure scurvy, and William Withering discovered the value of digitalis in treating edema and heart disease.

In 1796, Edward Jenner developed a vaccination against the virus that caused smallpox. Subjects were inoculated with a semm containing material from cowpox - the bovine form of the disease - and were found to be immune from smallpox when they were exposed to it later. Although it took another 50 years to find an effective method of producing this antiviral medication in volume, Jenner's early work was responsible for eradicating the disease.

In the 18th century, physicians created the foundation for modem hospitals, where treatment and restored health, rather than containment and death, were attainable goals, and the first medical school in the United States was established at the University of Pennsylvania. At the same time, Philippe Pinel, a French physician, pioneered the humane treatment of the mentally ill, discarding the long-held belief that mental illness was caused by demonic possession. (The New York Times ‘Smarter by Sunday – 52 Weekends of Essential Knowledge for the Curious Mind’)