Louis Pasteur: The Doctor Who Championed Handwashing And Briefly Saved Lives

What is A Scientific Theory?

The purpose of a scientific theory is to gather data that explicates the cause for natural phenomena by hypothesizing and establishing a connection between distinct factors which result in the event, which is achieved through numerous experiments which incorporate scientific laws and are repeated, to determine the reliability of the results, which enables scientists to predict what observations should be visible in their tests to support the theory. In contrast, because of the continuous advancements in science and technology which result in the work of future scientists contradicting the previous principles of a theory, scientific theories never stop undergoing modification or rejection.

What is The Scientific Method?

Scientists follow the scientific method when researching the integration of mathematical practises help scientists to accumulate measurable and empirical evidence is a fair, logical, and rational way for scientists to prove or disprove their hypothesis. Within this iterative process, there are six focal stages, which include: making an initial observation that concerns a noticeable problem, forming a question(s) regarding the cause of the issue, researching preceding studies of other scientists, accumulate and examining evidence to help construct a hypothesis, which is a suggestive visual interpretation of the cause and solution of the issue which is testable, directing and predicting the result of the unbiased experiment(s) which will evaluate the validity of the hypothesis, analyzing the data obtained from these tests to arrive at a conclusion which will refine the theory, and communicating your results to others (Bradford. A, 2017).

What is Germ Theory?

In medicine, the Germ theory of disease is the theory which believes the cause of infectious diseases is due to microorganisms or germs which invade our body.

While working in a general hospital in Vienna in a maternity ward, physicist Ignaz Semmelweis wanted to figure out why so many women were dying from puerperal fever or childbed fever. Desperate to comprehend the origin of what was causing this epidemic, Semmelweis studied two maternity wards, one which was only staffed by male doctors and medical students and one which was staffed by only female midwives (Davis. R, 2015). By counting and comparing the number of deaths related to puerperal fever on both wards, he recognised the mortality rate on the ward staffed by male doctors and medical students were nearly five times higher. Initially, Semmelweis thought the number of deaths caused by puerperal fever differed by how women were giving birth, e.g. the mortality rate was lower women gave birth on their back instead of their side, so he trialled women in the doctor ward giving birth in the same position, but it did not affect the mortality rates. So, he looked for other differences, where he then noticed whenever a woman on the ward died of puerperal fever in the doctors’ ward, a priest would slowly walk past the woman’s beds and ring a bell; so he stopped the priest from entering the doctors’ ward, which still changed nothing. However, when he found out a pathologist had died as a result of accidentally being poked with a scalpel while performing a post mortem examination on a victim of puerperal fever, his autopsy results revealed puerperal fever was the cause of death; which revealed women were not the only people who could get the disease, and there was a connection amidst cadaveric contamination and puerperal fever. In following this up, further investigation found only the doctors’ ward was performing autopsies and the medical students who dissected the bodies, were returning to the maternity ward without washing their hands, and were transferring unknown cadaveric particles (hemolytic streptococcus bacteria) from those who had died of puerperal fever to healthy patients. Consequently, to review the efficiency of his hypothesis, in 1847 he made staff to wash their hands with a chlorinated lime solution (calcium hypochlorite), before examining women and delivering babies; which was doubted and viewed as odd because of the association people had with water and certain diseases, e.g. those who lived in parts of the world with poor sanitation and contaminated water was at risk of contracting typhoid fever, resulted in mortality rates dropping from 18.27% to 1.27% (Zoltan, I, 2020), the obstetrician’s medical breakthrough was widely opposed by doctors since they refused to believe they were accountable for passing on infection which led to the deaths of their patients, and overall resisted to be accredited because not only did it conflict with the conventional theories of what caused disease (in the 19th century), e.g. the theory of miasma, which stated diseases were contracted by inhaling impure air, and the theory of the four humours proposed by Hippocrates and developed by Galen, which argued the body was comprised of four elements (phlegm, blood, yellow bile, black bile) and the imbalance of either fluid caused illness, which were preventable if the opposite environment was applied to the imbalanced humour (Gill. S. N, 2019), Semmelweis could not justify how a disinfectant reduced disease. Hence why regardless of his evident success, due to constant criticism for his doctrine, Semmelweis attended only a few lectures in Vienna during the 1850’s, to vocalize his thoughts, before eventually publishing his results in 1861, into a book called Die Aetiologie, der Begriff und die Prophylaxis des Kindbettfiebers or the etiology, concept, and prophylaxis of childbed fever.

In sequence, the work of chemist and microbiologist Louis Paster significantly impacted scientists understanding of diseases by developing his germ theory which proved bacteria caused disease and by disproving the spontaneous generation theory in all organisms, which before was only disproved for meat following the Italian scientists Francesco Redi’s controlled experiment in 1668 (Lumen Learning, n.d.). The spontaneous generation theory was developed by Aristotle, which conditioned that living organisms developed from inanimate matter, e.g. fleas formed from dust, or in regards to fermentation, the spontaneous generation theory meant most scientists believed that air was able to convert sugar into alcohol, which was invalidated by Pasteur when he launched his studies on fermentation in 1856, where he was able to show that fermentation is chemically broken down by the growth of microbes such as yeast converts sugar into alcohol in the absence of air, which was referred to as the germ theory of fermentation and in 1857, where, by isolating the microorganisms in lactic acid (which form during the acidification process which gives milk a sour taste), to grow them in cultures, to speed up the process of lactic acid fermentation, by adding the cultivated lactic acid culture to fresh milk, which demonstrated microorganisms were responsible for souring milk. This germ theory of fermentation was significant since it led to Pasteur’s development of the theory of disease by additionally being able to disprove spontaneous generation causing disease. Pasteur further disproved Felix Pouchet’s heterogenetic judgement who argued spontaneous generation was the cause of decay, which he attempted to prove by claiming when he performed Theodor Schwann’s experiment (who was convinced that the absence of microbes when oxygen was heated in a vessel was due to the air being destroyed by the heat, insinuated the philosophies of spontaneous generation were incorrect), microorganisms grew. On the contrary, scientists did not accept his results because the practical was poorly conducted as Pouchet failed to effectively control and certify there his equipment was not contaminated by dust. In 1861, Pasteur discredited this notion through his swan-neck experiment, where he heated an infusion sealed in a “swan neck” vessel to sterilize the vessel and left it to cool before he broke the tip of the vessel, which permitted direct exposure for air and the bend in the s-shaped vessel used gravity to trap any airborne substances. Consequently, given no bacteria formed in the culture, the idea that non-living material, e.g. air could cause decay, was disproved as, despite the culture having access to air, no microorganisms were produced as a result (Harris. W, n.d.).