18th Century Scientific Advancements and Germ Theory

18th Century Scientific Advancements and Germ Theory

• The Enlightenment fostered a shift from religious explanations to scientific ones for disease and illness.
• The Scientific Revolution, encompassing both discrediting old theories and developing new ones.
• Urban growth and poor sanitation contributed to widespread infectious diseases like tuberculosis, typhus, and smallpox.
• Understanding disease causes became crucial in the face of these issues.

Early Theories of Disease

• The Four Humours theory was outdated.
• Miasma theory, while prevalent, lost popularity.
• The theory of spontaneous generation presented an alternative, proposing that microbes arise spontaneously from decaying matter. Microscopes revealed microbes on decaying matter, leading to their presence being associated with decay.

Germ Theory's Development

• Louis Pasteur's experiments disproved spontaneous generation, showcasing that air-borne substances caused decay. This was published in 1861.
• Pasteur linked decay in non-living things to similarly caused disease in living things. Yet he did not publicize this germ theory of infection to the public until 1878.
• Pasteur's work had restricted influence in Britain where Dr. Henry Bastian initially held the dominant view on spontaneous generation.
• John Tyndall, despite not being a physician, linked microscopic organic particles in the air to Pasteur's germ theory and Lister's studies on infection. His 1870 lecture linked germs to disease.
• Joseph Lister, a surgeon, attempted to link observed infections to microbes, foreshadowing the idea that specific germs caused disease.
• Despite the evidence, doctors held onto a preference to existing ideas about disease.

Robert Koch's Contributions

• German scientist Robert Koch identified the bacteria responsible for tuberculosis in 1882.
• Koch developed a four-point method for identifying disease-causing microbes:
• Microbe is present in every case of the disease.
• Microbe can be grown in a pure culture.
• Disease can be reproduced in test animals.
• Microbes can reproduce the disease.
• He expanded the methods with his experiments on cholera in India, proving water contamination.
• Koch developed methods of growing and staining microbes to improve their analysis. This method is still employed today.

Impact and Acceptance of Germ Theory in Britain

• Initial slow acceptance of germ theory by the medical community and British government.
• Governments prioritized other causes for diseases like cholera; for instance, miasma in relation to outbreaks during rainy seasons due to weather patterns.
• Koch's findings were disregarded by the British public.
• Eventually germ theory significantly advanced the understanding of disease and its causes in the 20th century.
• Doctors became able to diagnose disease and understand its cause.

Factors influencing Germ Theory's development

• Individuals: Pasteur and Koch were key figures, crucial in its development.
• Institutions: The British government initially resisted the theory despite evidence of water contamination being linked to cholera outbreaks.
• Science: Strong motivation to prove theories and address practical issues of public health. Improved communication among scientists.
• Technology: The microscope was crucial for identifying microbes. Koch's methodology and petri dish innovation streamlined bacterial study. Dyes also improved analysis.
• Social Attitudes: People showed an increasing interest in rational explanations for illness, influenced by the Enlightenment. But skepticism about changes in established thought delayed widespread acceptance.