Rene Laennec's Invention of the Stethoscope

René-Théophile-Hyacinthe Laennec was a French physician who invented the stethoscope in 1816. When he was thirty five years old walking in the fields, he saw two boys sending signals to each other by using long  solid wood and a pin. The boys holding the ear in one end would receive amplified sound when the pin scratched. Later he was brought to a plump lady with symptoms of a heart disease. He was reluctant to start immediate auscultation due to age, sex and plumpness of the patient. Immediate auscultation is the art of placing the doctor’s ear to the patient’s chest. He rolled a piece of paper which he placed in the precordium of the patient and the other to his ear. With this, he was able to hear the beat of the heart more clearly than he ever did with his ears. He saw this as a method to study the beatings of the heart and movements able to produce sound in the chest cavity. He later observed that the heart sounds could be heard more clearly with mediate auscultation than with immediate auscultation. This led to him testing different materials he could be use to make tubes to perfect his ability to listen to patient’s chest that had pneumonia. He was able to relate sounds captured by his new stethoscope with specific pathological changes in the chest. He pioneered a new non invasive diagnostic tool. Laennec was the first to discuss the terms rales, rhonchi, crepitance and egophony which are still used by doctors today during a physical examination and diagnosis. He phrase the term mediate auscultation to the opposed popular practice of the time immediate auscultation.

Clinical Contribution

Before stethoscope was invented, physicians had limited means at their hands to unravel the mysteries of the chest. Laennec was influenced by his teachers (Corvisart) teachings which   stressed beyond examinations and autopsy study. He followed up his teacher’s idea. After several years of proper study and clinical observation, he published his findings. This laid down the foundation of modern knowledge of chest diseases.

Auscultation: Immediate and Mediate

The only available option to an early 19th century physician was the old practice of direct or immediate auscultation .this was the direct listening to the chest sound and heart beats by direct pressing of the ear to the chest wall. It was practiced in ancient Greece, but it was not an ideal way to examine patients. This is because some of the patients were too obese for sounds to be heard. If the sounds were heard, they were way too faint and muffled. This made it hard for physicians to interpret them. Some patients did not bath; others had infections making it hard for physicians to listen directly. However, some patients like women required modesty. Laennec’s introduction of mediate auscultation using a stethoscope to listen lungs and chest sounds and heart beats revolutionalized medicine. He presented this findings and research on the stethoscope to the Academy of Science in Paris in 1818.His work was recognized to be one great advancement in the required knowledge of heart diseases. He later embarked in a revised edition of his epochal work which masterfully related stethoscopic sounds and diseases of the chest documented by postmortem findings (Echenberg 2011). Laennec’s essay raised interest abroad, and physicians all over Europe flocked in Paris to get firsthand experience for the use of the tool. The section of the heart is not as significant as that of the chest because very little physiology of the heart was understood. However, Laennec was able to distinguish two heart sounds attributing the first sound to the ventricular systole and the second sound to the atiole systole. This knowledge has helped the modern physicians to deal with their patients in a more professional manner.

Steven Johnson; John Snow: On the Mode of Cholera

Cholera is not propagated by effluvium as some want to say. When one gets cholera, as the writer observes, the alimentary canal gets affected first. The symptoms at first are not consecutive, and the results of the local affection are not clear. Depression and lassitude precede the evacuation from the bowel. The exudation from the watery part of the blood which is copiously discharged takes place in the mucus membrane. During the early stages, there are little feelings of illness that the suffering patient cannot persuade himself that he got cholera. He is not in a position to apply remedies until at advanced stages, the stages that increase mortality. The amount of fluid lost by purging and vomiting having in mind the previous state of the patient and the sudden attack. If the fluid is not replaced by absorption, or is less sufficient, it becomes fatal to the patient. The quantity and composition of blood changes, making it difficult for the patient to breath. The patient collapses and dies due to loss of large amounts of fluid.

When Asiatic cholera broke out in England, it killed mercilessly. Different cases concerning the disease made the health officers in the region declare that cholera was transmitted. In some cases, a person infected with cholera was visited by a relative. For just two hours visit, the relative got sick and died. This became the norm, where cholera became an easily transmitted disease. At a point when one victim died and her clothes transported to her relatives unwashed, the relative contracted the disease and died. One man visited his sick relative together with his family. On going back to New York, he discovered he had contracted the disease and died some hours later. There had been no case concerning cholera in the USA. Snow was sceptic of the dominant theory that stated that the main cause for cholera was pollution or a noxious from of polluted air (Coleman 1998). The germ theory of disease had not been developed, so Snow did not quite understand how the disease was transmitted. He observed the evidence which made him discount the theory of foul air. He mixed with the residents where he made inquiries. He identified the source of the outbreak to be public water plant from the Broad Street. Snows chemical and microscope examination of water sample did not prove its danger. However, through his studies and patterns, he was able to convince and persuade the local council to restrict the water pump by removing its handle. The action was credited as the one ending the outbreak, but Snow observed that the epidemic could have already inclined. He later used a dot map to illustrate cluster of cholera cases around the map.hu then used statistics it study the relation  between  quality of water  source  and  the cholera cases. He showed that a section of the people in the street took water from sewage polluted sections and taking them home. This lead to increased cases of cholera. He discovered that the majority that died were livings near the well and that they used to take water occasionally. Most of the deceased were students in a nearby school.

Later researchers found that the well was dug only three feet from an old cesspit which had begun to leak fecal bacteria. There were nappies of a baby who had collected cholera from another source had washed in the cesspit. Snow discovered the main cause of the outbreak which helped the people to prevent other outbreaks.

Louis Pasteur Vaccination Theory

Louis Pasteur discovered that micro organisms were responsible for spoiling beverages such as wine and milk. Beverages contamination led him to the discovery that microorganisms infecting animals and human beings cause diseases. The medical establishment was reluctant to accept his theory of germ theory of disease since it came from a chemist. However, Pasteur discovered the principle of vaccination which later lead to the foundation of immunology. His fast major discovery came when he was dealing with a chicken cholera case. He observed that cultures of chicken cholera lost their pathogenicity and retained a pathogenic characteristic which was termed as attenuated. This happened over the course of many generations. He distinguished chickens with the attenuated form and shown that this chicken were resistant to the fully virulent strain. He later directed this to all this work to the problem of immunization. He also used it to tackle other problems.

Later on he started investigating anthrax which had killed a number of sheep and had started attacking human being as well. He wanted to apply the principle of vaccination to anthrax. He discovered that anthrax bacillus was responsible for the infection. He prepared attenuated cultures of the bacillus. This was after determining the factors which led to the animals’ loss of virulence. He conducted a large scale immunization of anthrax. This was done with the aid of financial support he got from the farmers. He immunized seventy animals which turned out to be a success. The vaccination exercise took two inoculations which took place at an interval of 12 days. They were of different potencies. He gave a low virulence culture vaccine to half of the sheep followed by a more virulence culture vaccine to the other half. Two weeks after these inoculations, the animals, control and vaccinated, were injected with a virulent strain anthrax bacteria. Within a few days, all the control sheep died, and the vaccinated sheep survived. This proved that his work was indeed valid (Birch 2007).

He later developed another vaccine against a virus. This virus were too small to be seen with his microscope .experimentation with this disease required him to develop new methodologies. Pasteur conducted his experiment using rabbits. He transmitted the infectious virus from animal to animal by use of intracerebral inoculations until he maintained a stable preparation. He desiccated the spinal cords of infected animals until this preparation became almost nonvirulent. This was to attenuate the invisible microbe. His treatment had killed many of the infectious animals instead of creating an annulated microbe. The vaccine was first used on a human being. This is when a boy who had been bitten by a dog was vaccinated by Louis Pasteur using this method. He was taking risks since he was not a qualified physician. The vaccine was successful. He was fearless. At one time, people saw him extract saliva from the jaws of a dog. This was influential to the other doctors. They started sanitizing their hands and surgery tools before work. Prior to this, they did not observe that.

The theoretical implications and practical work are Louis Pasteur   is immense. They have been used in the field medicine since then. They are beneficial to the people. With the many infectious diseases that have risen in the past years, vaccination has helped in preventing massive death of people. There is prevention of diseases which usually attacks children. These include polio, measles and chicken pox. Vaccinating against these diseases has helped in preventing outbreaks of the diseases which have proven to be fatal if not taken care of.