Many infectious diseases are caused by bacteria or viruses, microorganisms invisible to the naked eye. Yet as late as the early 20th century, a surprisingly large number of practicing physicians did not believe germs existed. First postulated in Europe, the germ theory of disease took quite some time to be accepted by American medical minds.
Countless patients died from sepsis after even minor surgeries. The 1918 influenza pandemic wiped out well over 21 million individuals, about half of whom were young and vigorous. Many of these flu victims died not from the disease itself, but from secondary bacterial infections. From this devastation, one ray of light emerged; doctors learned through experience that the germ theory was correct and that antiseptics could prevent the spread of some types of infection.
The Filth and Miasma Theories of Disease
Competing with germ theory as the primary explanation for the spread of contagion were two other hypotheses: the filth theory and the miasma theory.
The filth theory sprang from poor 19th century sanitation, especially obvious in poorly maintained sewers and outhouses, which were said to release “swamp gases” that carried disease. In the Victorian era, anything even remotely connected with bodily functions was at least presumed to be distasteful and unhealthy; so this theory became quite popular.
Moreover, the poor as a class were associated with crowded and dirty living conditions, so the filth theory gave the privileged a way to blame the “disgusting” lower classes for the spread of disease. However, it provided no explanation for exactly how infections spread within the body or moved from human host to human host.
The miasma theory held that bad air caused illnesses. Changes in air pressure or climate were believed to spread disease due to rot in the atmosphere. Patients were advised to keep all doors and windows tightly closed and breathe no fresh air. Well into the 1930s, more than a few diehards clung adamantly to this theory.
Chemistry’s Zymote Theory of Disease
A third rival theory came closest to the truth. Formulated by chemists, it was known as the zymote theory. According to this school of thought, tiny molecules called “zymes” carried illnesses. They acted as catalysts to spread raging infections, much as the striking of a single match could start a fierce conflagration.
Although the science behind zymote theory was not wholly correct by any means, it was the best early attempt to describe a viral attack on the body.
Dr. Joseph Lister Proved the Germ Theory Correct
Dr. Lister was a Quaker physician who was born in Yorkshire, England, in 1827. An early believer in germ theory, Dr. Lister was a devotee of the work of Louis Pasteur. Lister began to clean wounds and spray his operating area with antiseptic, first using coal-tar-derived carbolic acid and later switching to its pure component of phenol.
Lister concocted a phenol paste and smeared it on sheets of tinfoil, making a “carbolic putty poultice” to dress open wounds. He also washed his hands and instruments with phenol prior to operating, and sprayed it into surgical incisions. Other surgeons utterly scorned these techniques until they noticed how many of Lister’s patients survived both his procedures and their recuperation periods as compared to their own patients’ appallingly low survival statistics.
Germ Theory’s Impact on Modern Medicine
Slowly but surely, all physicians came to accept the germ theory and to use antiseptics to prevent or reverse certain types of infections. Later antiseptics were much safer than the extremely toxic phenol, and sterilization procedures were refined considerably. For example, Lister had believed that particles of dust carried germs; so he’d installed a device in his operating room that kept the air continually filled with a fine mist of phenol. This practice was eventually discontinued as overkill.
The germ theory led to the discovery of organisms that caused cholera, tuberculosis, and countless other killers; it helped scientists develop effective treatments for them as well. Varied disinfectants were developed for different strains of microorganisms. As a consequence, public health and wellbeing improved immeasurably.
Less than one hundred years ago, some doctors still scoffed at the idea of tiny invisible germs that made patients sick. One hundred years from now, the achievements and advancements of medicine will doubtless be unimaginable by the “primitive standards” of today.
Readers of this article may also enjoy “Early Germ Theory of Disease” and “Late Germ Theory of Disease” in Suite 101’s Science & Nature section.
Sources
Barry, John M., The Great Influenza, New York: Viking, 2004.
Burreson, Jay and Le Couteur, Penny, Napoleon’s Buttons: 17 Molecules That Changed History, New York: Jeremy P. Tarcher/Penguin, 2003.
Kusinitz, Marc, “Germ Theory,” 2010.
Amy Sillup - I have a B.S. in Chemistry from Delaware Valley College and a Juris Doctorate from the University of Pennsylvania. I have worked as a ...
Join the Conversation