{"id":60,"date":"2016-11-04T03:32:34","date_gmt":"2016-11-04T03:32:34","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/microbiology\/?post_type=chapter&#038;p=60"},"modified":"2018-07-11T18:25:21","modified_gmt":"2018-07-11T18:25:21","slug":"what-our-ancestors-knew","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/chapter\/what-our-ancestors-knew\/","title":{"raw":"What Our Ancestors Knew","rendered":"What Our Ancestors Knew"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\n<ul>\r\n \t<li>Describe how our ancestors improved food with the use of invisible microbes<\/li>\r\n \t<li>Describe how the causes of sickness and disease were explained in ancient times, prior to the invention of the microscope<\/li>\r\n \t<li>Describe key historical events associated with the birth of microbiology<\/li>\r\n<\/ul>\r\n<\/div>\r\nMost people today, even those who know very little about microbiology, are familiar with the concept of microbes, or \"germs,\" and their role in human health. Schoolchildren learn about bacteria, viruses, and other microorganisms, and many even view specimens under a microscope. But a few hundred years ago, before the invention of the microscope, the existence of many types of microbes was impossible to prove. By definition, <strong>microorganisms<\/strong>, or <strong>microbes<\/strong>, are very small organisms; many types of microbes are too small to see without a microscope, although some parasites and fungi are visible to the naked eye.\r\n\r\nHumans have been living with\u2014and using\u2014microorganisms for much longer than they have been able to see them. Historical evidence suggests that humans have had some notion of microbial life since prehistoric times and have used that knowledge to develop foods as well as prevent and treat disease. In this section, we will explore some of the historical applications of microbiology as well as the early beginnings of microbiology as a science.\r\n<h2>Fermented Foods and Beverages<\/h2>\r\nPeople across the world have enjoyed fermented foods and beverages like beer, wine, bread, yogurt, cheese, and pickled vegetables for all of recorded history. Discoveries from several archeological sites suggest that even prehistoric people took advantage of <strong>fermentation<\/strong> to preserve and enhance the taste of food. Archaeologists studying pottery jars from a Neolithic village in China found that people were making a fermented beverage from rice, honey, and fruit as early as 7000 BC.[footnote]P.E. McGovern et al. \"Fermented Beverages of Pre- and Proto-Historic China.\" <em>Proceedings of the National Academy of Sciences of the United States of America<\/em> 1 no. 51 (2004):17593\u201317598. doi:10.1073\/pnas.0407921102.[\/footnote]\r\n\r\nProduction of these foods and beverages requires microbial fermentation, a process that uses bacteria, mold, or yeast to convert sugars (carbohydrates) to alcohol, gases, and organic acids (see Figure\u00a02). While it is likely that people first learned about fermentation by accident\u2014perhaps by drinking old milk that had curdled or old grape juice that had fermented\u2014they later learned to harness the power of fermentation to make products like bread, cheese, and wine.\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"1200\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153409\/OSC_Microbio_01_01_ferment.jpg\" alt=\"The Figure\u00a0on the left shows oval cells with smaller oval cells budding from the larger cells. An arrow points to a mason jar containing a creamy textured thick liquid. Another arrow points to a loaf of bread.\" width=\"1200\" height=\"367\" \/> Figure\u00a02. A microscopic view of <em>Saccharomyces cerevisiae<\/em>, the yeast responsible for making bread rise (left). Yeast is a microorganism. Its cells metabolize the carbohydrates in flour (middle) and produce carbon dioxide, which causes the bread to rise (right). (credit middle: modification of work by Janus Sandsgaard; credit right: modification of work by \"MDreibelbis\"\/Flickr)[\/caption]\r\n<h2>The Iceman Treateth<\/h2>\r\nPrehistoric humans had a very limited understanding of the causes of disease, and various cultures developed different beliefs and explanations. While many believed that illness was punishment for angering the gods or was simply the result of fate, archaeological evidence suggests that prehistoric people attempted to treat illnesses and infections. One example of this is \u00d6tzi the Iceman, a 5300-year-old mummy found frozen in the ice of the \u00d6tzal Alps on the Austrian-Italian border in 1991. Because \u00d6tzi was so well preserved by the ice, researchers discovered that he was infected with the eggs of the parasite <em>Trichuris trichiura<\/em>, which may have caused him to have abdominal pain and anemia. Researchers also found evidence of <em>Borrelia burgdorferi<\/em>, a bacterium that causes Lyme disease.[footnote]A. Keller et al. \"New Insights into the Tyrolean Iceman's Origin and Phenotype as Inferred by Whole-Genome Sequencing.\" <em>Nature Communications<\/em>, 3 (2012): 698. doi:10.1038\/ncomms1701.[\/footnote]\u00a0Some researchers think \u00d6tzi may have been trying to treat his infections with the woody fruit of the <em>Piptoporus betulinus<\/em> fungus, which was discovered tied to his belongings.[footnote]L. Capasso. \"5300 Years Ago, the Ice Man Used Natural Laxatives and Antibiotics.\" <em>The Lancet<\/em>, 352 (1998) 9143: 1864. doi: 10.1016\/s0140-6736(05)79939-6.[\/footnote] This fungus has both laxative and antibiotic properties. \u00d6tzi was also covered in tattoos that were made by cutting incisions into his skin, filling them with herbs, and then burning the herbs.[footnote]L. Capasso, L. \"5300 Years Ago, the Ice Man Used Natural Laxatives and Antibiotics.\" <em>The Lancet<\/em>, 352 no. 9143 (1998): 1864. doi: 10.1016\/s0140-6736(05)79939-6.[\/footnote]\u00a0There is speculation that this may have been another attempt to treat his health ailments.\r\n<h2>Early Notions of Disease, Contagion, and Containment<\/h2>\r\nSeveral ancient civilizations appear to have had some understanding that disease could be transmitted by things they could not see. This is especially evident in historical attempts to contain the spread of disease. For example, the Bible refers to the practice of quarantining people with leprosy and other diseases, suggesting that people understood that diseases could be communicable. Ironically, while leprosy is communicable, it is also a disease that progresses slowly. This means that people were likely quarantined after they had already spread the disease to others.\r\n\r\nThe ancient Greeks attributed disease to bad air, <em>mal\u2019aria<\/em>, which they called \"miasmatic odors.\" They developed hygiene practices that built on this idea. The Romans also believed in the miasma hypothesis and created a complex sanitation infrastructure to deal with sewage. In Rome, they built aqueducts, which brought fresh water into the city, and a giant sewer, the <em>Cloaca Maxima<\/em>, which carried waste away and into the river Tiber (see Figure\u00a03). Some researchers believe that this infrastructure helped protect the Romans from epidemics of waterborne illnesses.\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"1301\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153414\/OSC_Microbio_01_01_cloaca.jpg\" alt=\"Figure\u00a0a is a map of a city containing a stadium, forum, and other structures. Running through the center of the city is a red line. Figure\u00a0b is a photograph of a corner of a room. There is a trough between the walls and the floor. This trough is covered with stone benches that have large holes (as for a toilet) in the bench. The holes span the top and front of the bench. There are six holes visible in the bench that runs along one side of the image and two more in the bench along the other side. The image does not show the entire room so there are likely more available spots in this room.\" width=\"1301\" height=\"1272\" \/> Figure\u00a03. (a) The <em>Cloaca Maxima<\/em>, or \"Greatest Sewer\" (shown in red), ran through ancient Rome. It was an engineering marvel that carried waste away from the city and into the river Tiber. (b) These ancient latrines emptied into the <em>Cloaca Maxima<\/em>.[\/caption]\r\n\r\nEven before the invention of the microscope, some doctors, philosophers, and scientists made great strides in understanding the invisible forces\u2014what we now know as microbes\u2014that can cause infection, disease, and death.\r\n\r\nThe Greek physician Hippocrates (460\u2013370 BC) is considered the \"father of Western medicine\" (Figure\u00a04a). Unlike many of his ancestors and contemporaries, he dismissed the idea that disease was caused by supernatural forces. Instead, he posited that diseases had natural causes from within patients or their environments. Hippocrates and his heirs are believed to have written the <em>Hippocratic Corpus<\/em>, a collection of texts that make up some of the oldest surviving medical books.[footnote]G. Pappas et al. \"Insights Into Infectious Disease in the Era of Hippocrates.\" <em>International Journal of Infectious Diseases<\/em> 12 (2008) 4:347\u2013350. doi: http:\/\/dx.doi.org\/10.1016\/j.ijid.2007.11.003.[\/footnote]\u00a0Hippocrates is also often credited as the author of the Hippocratic Oath, taken by new physicians to pledge their dedication to diagnosing and treating patients without causing harm.\r\n\r\nWhile Hippocrates is considered the father of Western medicine, the Greek philosopher and historian Thucydides (460\u2013395 BC) is considered the father of scientific history because he advocated for evidence-based analysis of cause-and-effect reasoning (Figure\u00a04b). Among his most important contributions are his observations regarding the Athenian plague that killed one-third of the population of Athens between 430 and 410 BC. Having survived the epidemic himself, Thucydides made the important observation that survivors did not get re-infected with the disease, even when taking care of actively sick people.[footnote]Thucydides. <em>The History of the Peloponnesian War. The Second Book<\/em>. 431 BC. Translated by Richard Crawley. http:\/\/classics.mit.edu\/Thucydides\/pelopwar.2.second.html.[\/footnote]\u00a0This observation shows an early understanding of the concept of immunity.\r\n\r\nMarcus Terentius Varro (116\u201327 BC) was a prolific Roman writer who was one of the first people to propose the concept that things we cannot see (what we now call microorganisms) can cause disease (Figure\u00a04c). In <em>Res Rusticae<\/em> (<em>On Farming<\/em>), published in 36 BC, he said that\r\n<blockquote>precautions must also be taken in neighborhood swamps . . . because certain minute creatures [<em>animalia minuta<\/em>] grow there which cannot be seen by the eye, which float in the air and enter the body through the mouth and nose and there cause serious diseases.[footnote]Plinio Prioreschi. <em>A History of Medicine: Roman Medicine<\/em>. Lewiston, NY: Edwin Mellen Press, 1998: p. 215.[\/footnote]<\/blockquote>\r\n[caption id=\"\" align=\"aligncenter\" width=\"1101\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153418\/OSC_Microbio_01_01_ancients.jpg\" alt=\"Figure\u00a0a is a drawing of a bust of Hippocrates. Figure\u00a0b is a photo of a sculpture of Thucydides\u2019s head. Figure\u00a0c is a photo of a sculpture of Marcus Terentius Varro.\" width=\"1101\" height=\"518\" \/> Figure\u00a04. (a) Hippocrates, the \"father of Western medicine,\" believed that diseases had natural, not supernatural, causes. (b) The historian Thucydides observed that survivors of the Athenian plague were subsequently immune to the infection. (c) Marcus Terentius Varro proposed that disease could be caused by \"certain minute creatures . . . which cannot be seen by the eye.\" (credit c: modification of work by Alessandro Antonelli)[\/caption]\r\n\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Think about It<\/h3>\r\n<ul>\r\n \t<li>Give two examples of foods that have historically been produced by humans with the aid of microbes.<\/li>\r\n \t<li>Explain how historical understandings of disease contributed to attempts to treat and contain disease.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>The Birth of Microbiology<\/h2>\r\nWhile the ancients may have suspected the existence of invisible \"minute creatures,\" it wasn\u2019t until the invention of the microscope that their existence was definitively confirmed. While it is unclear who exactly invented the microscope, a Dutch cloth merchant named Antonie van Leeuwenhoek (1632\u20131723) was the first to develop a lens powerful enough to view microbes. In 1675, using a simple but powerful microscope, Leeuwenhoek was able to observe single-celled organisms, which he described as \"animalcules\" or \"wee little beasties,\" swimming in a drop of rain water. From his drawings of these little organisms, we now know he was looking at bacteria and protists. (We will explore Leeuwenhoek\u2019s contributions to microscopy further in <a class=\"target-chapter\" href=\".\/chapter\/introduction-to-how-we-see-the-invisible-world\/\">How We See the Invisible World<\/a>.)\r\n\r\nNearly 200 years after van Leeuwenhoek got his first glimpse of microbes, the \"Golden Age of Microbiology\" spawned a host of new discoveries between 1857 and 1914. Two famous microbiologists, Louis Pasteur and Robert Koch, were especially active in advancing our understanding of the unseen world of microbes (Figure\u00a05). Pasteur, a French chemist, showed that individual microbial strains had unique properties and demonstrated that fermentation is caused by microorganisms. He also invented pasteurization, a process used to kill microorganisms responsible for spoilage, and developed vaccines for the treatment of diseases, including rabies, in animals and humans. Koch, a German physician, was the first to demonstrate the connection between a single, isolated microbe and a known human disease. For example, he discovered the bacteria that cause anthrax (<em>Bacillus anthracis<\/em>), cholera (<em>Vibrio cholera<\/em>), and tuberculosis (<em>Mycobacterium tuberculosis<\/em>).[footnote]S.M. Blevins and M.S. Bronze. \"Robert Koch and the \u2018Golden Age\u2019 of Bacteriology.\" <em>International Journal of Infectious Diseases<\/em>. 14 no. 9 (2010): e744-e751. doi:10.1016\/j.ijid.2009.12.003.[\/footnote] We will discuss these famous microbiologists, and others, in later chapters.\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"1100\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153421\/OSC_Microbio_01_01_PastKoch.jpg\" alt=\"Figure\u00a0a is a drawing of Louis Pasteur in his lab. Figure\u00a0b is a photograph of Robert Koch.\" width=\"1100\" height=\"682\" \/> Figure\u00a05. (a) Louis Pasteur (1822\u20131895) is credited with numerous innovations that advanced the fields of microbiology and immunology. (b) Robert Koch (1843\u20131910) identified the specific microbes that cause anthrax, cholera, and tuberculosis.[\/caption]\r\n\r\nAs microbiology has developed, it has allowed the broader discipline of biology to grow and flourish in previously unimagined ways. Much of what we know about human cells comes from our understanding of microbes, and many of the tools we use today to study cells and their genetics derive from work with microbes.\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Think about It<\/h3>\r\nHow did the discovery of microbes change human understanding of disease?\r\n\r\n<\/div>\r\n<div class=\"textbox shaded\">\r\n<h3>Microbiology Toolbox<\/h3>\r\nBecause individual microbes are generally too small to be seen with the naked eye, the science of microbiology is dependent on technology that can artificially enhance the capacity of our natural senses of perception. Early microbiologists like Pasteur and Koch had fewer tools at their disposal than are found in modern laboratories, making their discoveries and innovations that much more impressive. Later chapters of this text will explore many applications of technology in depth, but for now, here is a brief overview of some of the fundamental tools of the microbiology lab.\r\n<ul>\r\n \t<li><strong>Microscopes<\/strong> produce magnified images of microorganisms, human cells and tissues, and many other types of specimens too small to be observed with the naked eye.<\/li>\r\n \t<li><strong>Stains and dyes<\/strong> are used to add color to microbes so they can be better observed under a microscope. Some dyes can be used on living microbes, whereas others require that the specimens be fixed with chemicals or heat before staining. Some stains only work on certain types of microbes because of differences in their cellular chemical composition.<\/li>\r\n \t<li><strong>Growth media<\/strong> are used to grow microorganisms in a lab setting. Some media are liquids; others are more solid or gel-like. A growth medium provides nutrients, including water, various salts, a source of carbon (like glucose), and a source of nitrogen and amino acids (like yeast extract) so microorganisms can grow and reproduce. Ingredients in a growth medium can be modified to grow unique types of microorganisms.<\/li>\r\n \t<li><strong>A Petri dish<\/strong> is a flat-lidded dish that is typically 10\u201311 centimeters (cm) in diameter and 1\u20131.5 cm high. Petri dishes made out of either plastic or glass are used to hold growth media (Figure\u00a06a).<\/li>\r\n \t<li><strong>Test tubes<\/strong> are cylindrical plastic or glass tubes with rounded bottoms and open tops. They can be used to grow microbes in broth, or semisolid or solid growth media.<\/li>\r\n \t<li>A <strong>Bunsen burner<\/strong> is a metal apparatus that creates a flame that can be used to sterilize pieces of equipment. A rubber tube carries gas (fuel) to the burner. In many labs, Bunsen burners are being phased out in favor of infrared <strong>microincinerators<\/strong>, which serve a similar purpose without the safety risks of an open flame.<\/li>\r\n \t<li>An <strong>inoculation loop<\/strong> is a handheld tool that ends in a small wire loop (Figure\u00a06b). The loop can be used to streak microorganisms on agar in a Petri dish or to transfer them from one test tube to another. Before each use, the inoculation loop must be sterilized so cultures do not become contaminated.<\/li>\r\n<\/ul>\r\n[caption id=\"\" align=\"aligncenter\" width=\"1100\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153425\/OSC_Microbio_01_01_Petri.jpg\" alt=\"Figure\u00a0a is a photograph of a round disk streaked with lines. The thickest lines go back and forth along an area spanning one fifth of the plate. The next fifth of the plate also has thick lines. The next fifth of the plate has thinner lines that are made of tiny dots. The final fifth of the pate only has large dots. Figure\u00a0b shows a hand holding a metal rod that is the diameter of a pretzel stick; projecting from tis is a thick wire that is formed into a loop at the end.\" width=\"1100\" height=\"499\" \/> Figure\u00a06. (a) This Petri dish filled with agar has been streaked with <em>Legionella<\/em>, the bacterium responsible for causing Legionnaire\u2019s disease. (b) An inoculation loop like this one can be used to streak bacteria on agar in a Petri dish. (credit a: modification of work by Centers for Disease Control and Prevention; credit b: modification of work by Jeffrey M. Vinocur)[\/caption]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Key Concepts and Summary<\/h3>\r\n<ul>\r\n \t<li><strong>Microorganisms<\/strong> (or <strong>microbes<\/strong>) are living organisms that are generally too small to be seen without a microscope.<\/li>\r\n \t<li>Throughout history, humans have used microbes to make fermented foods such as beer, bread, cheese, and wine.<\/li>\r\n \t<li>Long before the invention of the microscope, some people theorized that infection and disease were spread by living things that were too small to be seen. They also correctly intuited certain principles regarding the spread of disease and immunity.<\/li>\r\n \t<li>Antonie van Leeuwenhoek, using a microscope, was the first to actually describe observations of bacteria, in 1675.<\/li>\r\n \t<li>During the Golden Age of Microbiology (1857\u20131914), microbiologists, including Louis Pasteur and Robert Koch, discovered many new connections between the fields of microbiology and medicine.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Multiple Choice<\/h3>\r\nWhich of the following foods is NOT made by fermentation?\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>beer<\/li>\r\n \t<li>bread<\/li>\r\n \t<li>cheese<\/li>\r\n \t<li>orange juice<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"809245\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"809245\"]Answer d. Orange juice is not made with fermentation.[\/hidden-answer]\r\n\r\nWho is considered the \"father of Western medicine\"?\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>Marcus Terentius Varro<\/li>\r\n \t<li>Thucydides<\/li>\r\n \t<li>Antonie van Leeuwenhoek<\/li>\r\n \t<li>Hippocrates<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"961496\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"961496\"]Answer d. Hippocrates is considered to be the father of Western medicine.[\/hidden-answer]\r\n\r\nWho was the first to observe \"animalcules\" under the microscope?\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>Antonie van Leeuwenhoek<\/li>\r\n \t<li>\u00d6tzi the Iceman<\/li>\r\n \t<li>Marcus Terentius Varro<\/li>\r\n \t<li>Robert Koch<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"774028\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"774028\"]Answer a. Antonie van Leeuwenhoek was the first to observe \"animalcules.\"[\/hidden-answer]\r\n\r\nWho proposed that swamps might harbor tiny, disease-causing animals too small to see?\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>Thucydides<\/li>\r\n \t<li>Marcus Terentius Varro<\/li>\r\n \t<li>Hippocrates<\/li>\r\n \t<li>Louis Pasteur<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"769727\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"769727\"]Answer b. Marcus Terentius Varro proposed that swamps might harbor tiny, disease-causing animals too small to see.[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Fill in the Blank<\/h3>\r\nThucydides is known as the father of _______________.\r\n[reveal-answer q=\"537429\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"537429\"]Thucydides is known as the father of <strong>scientific history<\/strong>. [\/hidden-answer]\r\n\r\nResearchers think that \u00d6tzi the Iceman may have been infected with _____ disease.\r\n[reveal-answer q=\"494540\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"494540\"]Researchers think that \u00d6tzi the Iceman may have been infected with <strong>Lyme<\/strong> disease.[\/hidden-answer]\r\n\r\nThe process by which microbes turn grape juice into wine is called _______________.\r\n[reveal-answer q=\"530716\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"530716\"]The process by which microbes turn grape juice into wine is called <strong>fermentation<\/strong>.[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Think about It<\/h3>\r\n<ol>\r\n \t<li>What did Thucydides learn by observing the Athenian plague?<\/li>\r\n \t<li>Why was the invention of the microscope important for microbiology?<\/li>\r\n \t<li>What are some ways people use microbes?<\/li>\r\n \t<li>Explain how the discovery of fermented foods likely benefited our ancestors.<\/li>\r\n \t<li>What evidence would you use to support this statement: Ancient people thought that disease was transmitted by things they could not see.<\/li>\r\n<\/ol>\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<ul>\n<li>Describe how our ancestors improved food with the use of invisible microbes<\/li>\n<li>Describe how the causes of sickness and disease were explained in ancient times, prior to the invention of the microscope<\/li>\n<li>Describe key historical events associated with the birth of microbiology<\/li>\n<\/ul>\n<\/div>\n<p>Most people today, even those who know very little about microbiology, are familiar with the concept of microbes, or &#8220;germs,&#8221; and their role in human health. Schoolchildren learn about bacteria, viruses, and other microorganisms, and many even view specimens under a microscope. But a few hundred years ago, before the invention of the microscope, the existence of many types of microbes was impossible to prove. By definition, <strong>microorganisms<\/strong>, or <strong>microbes<\/strong>, are very small organisms; many types of microbes are too small to see without a microscope, although some parasites and fungi are visible to the naked eye.<\/p>\n<p>Humans have been living with\u2014and using\u2014microorganisms for much longer than they have been able to see them. Historical evidence suggests that humans have had some notion of microbial life since prehistoric times and have used that knowledge to develop foods as well as prevent and treat disease. In this section, we will explore some of the historical applications of microbiology as well as the early beginnings of microbiology as a science.<\/p>\n<h2>Fermented Foods and Beverages<\/h2>\n<p>People across the world have enjoyed fermented foods and beverages like beer, wine, bread, yogurt, cheese, and pickled vegetables for all of recorded history. Discoveries from several archeological sites suggest that even prehistoric people took advantage of <strong>fermentation<\/strong> to preserve and enhance the taste of food. Archaeologists studying pottery jars from a Neolithic village in China found that people were making a fermented beverage from rice, honey, and fruit as early as 7000 BC.<a class=\"footnote\" title=\"P.E. McGovern et al. &quot;Fermented Beverages of Pre- and Proto-Historic China.&quot; Proceedings of the National Academy of Sciences of the United States of America 1 no. 51 (2004):17593\u201317598. doi:10.1073\/pnas.0407921102.\" id=\"return-footnote-60-1\" href=\"#footnote-60-1\" aria-label=\"Footnote 1\"><sup class=\"footnote\">[1]<\/sup><\/a><\/p>\n<p>Production of these foods and beverages requires microbial fermentation, a process that uses bacteria, mold, or yeast to convert sugars (carbohydrates) to alcohol, gases, and organic acids (see Figure\u00a02). While it is likely that people first learned about fermentation by accident\u2014perhaps by drinking old milk that had curdled or old grape juice that had fermented\u2014they later learned to harness the power of fermentation to make products like bread, cheese, and wine.<\/p>\n<div style=\"width: 1210px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153409\/OSC_Microbio_01_01_ferment.jpg\" alt=\"The Figure\u00a0on the left shows oval cells with smaller oval cells budding from the larger cells. An arrow points to a mason jar containing a creamy textured thick liquid. Another arrow points to a loaf of bread.\" width=\"1200\" height=\"367\" \/><\/p>\n<p class=\"wp-caption-text\">Figure\u00a02. A microscopic view of <em>Saccharomyces cerevisiae<\/em>, the yeast responsible for making bread rise (left). Yeast is a microorganism. Its cells metabolize the carbohydrates in flour (middle) and produce carbon dioxide, which causes the bread to rise (right). (credit middle: modification of work by Janus Sandsgaard; credit right: modification of work by &#8220;MDreibelbis&#8221;\/Flickr)<\/p>\n<\/div>\n<h2>The Iceman Treateth<\/h2>\n<p>Prehistoric humans had a very limited understanding of the causes of disease, and various cultures developed different beliefs and explanations. While many believed that illness was punishment for angering the gods or was simply the result of fate, archaeological evidence suggests that prehistoric people attempted to treat illnesses and infections. One example of this is \u00d6tzi the Iceman, a 5300-year-old mummy found frozen in the ice of the \u00d6tzal Alps on the Austrian-Italian border in 1991. Because \u00d6tzi was so well preserved by the ice, researchers discovered that he was infected with the eggs of the parasite <em>Trichuris trichiura<\/em>, which may have caused him to have abdominal pain and anemia. Researchers also found evidence of <em>Borrelia burgdorferi<\/em>, a bacterium that causes Lyme disease.<a class=\"footnote\" title=\"A. Keller et al. &quot;New Insights into the Tyrolean Iceman's Origin and Phenotype as Inferred by Whole-Genome Sequencing.&quot; Nature Communications, 3 (2012): 698. doi:10.1038\/ncomms1701.\" id=\"return-footnote-60-2\" href=\"#footnote-60-2\" aria-label=\"Footnote 2\"><sup class=\"footnote\">[2]<\/sup><\/a>\u00a0Some researchers think \u00d6tzi may have been trying to treat his infections with the woody fruit of the <em>Piptoporus betulinus<\/em> fungus, which was discovered tied to his belongings.<a class=\"footnote\" title=\"L. Capasso. &quot;5300 Years Ago, the Ice Man Used Natural Laxatives and Antibiotics.&quot; The Lancet, 352 (1998) 9143: 1864. doi: 10.1016\/s0140-6736(05)79939-6.\" id=\"return-footnote-60-3\" href=\"#footnote-60-3\" aria-label=\"Footnote 3\"><sup class=\"footnote\">[3]<\/sup><\/a> This fungus has both laxative and antibiotic properties. \u00d6tzi was also covered in tattoos that were made by cutting incisions into his skin, filling them with herbs, and then burning the herbs.<a class=\"footnote\" title=\"L. Capasso, L. &quot;5300 Years Ago, the Ice Man Used Natural Laxatives and Antibiotics.&quot; The Lancet, 352 no. 9143 (1998): 1864. doi: 10.1016\/s0140-6736(05)79939-6.\" id=\"return-footnote-60-4\" href=\"#footnote-60-4\" aria-label=\"Footnote 4\"><sup class=\"footnote\">[4]<\/sup><\/a>\u00a0There is speculation that this may have been another attempt to treat his health ailments.<\/p>\n<h2>Early Notions of Disease, Contagion, and Containment<\/h2>\n<p>Several ancient civilizations appear to have had some understanding that disease could be transmitted by things they could not see. This is especially evident in historical attempts to contain the spread of disease. For example, the Bible refers to the practice of quarantining people with leprosy and other diseases, suggesting that people understood that diseases could be communicable. Ironically, while leprosy is communicable, it is also a disease that progresses slowly. This means that people were likely quarantined after they had already spread the disease to others.<\/p>\n<p>The ancient Greeks attributed disease to bad air, <em>mal\u2019aria<\/em>, which they called &#8220;miasmatic odors.&#8221; They developed hygiene practices that built on this idea. The Romans also believed in the miasma hypothesis and created a complex sanitation infrastructure to deal with sewage. In Rome, they built aqueducts, which brought fresh water into the city, and a giant sewer, the <em>Cloaca Maxima<\/em>, which carried waste away and into the river Tiber (see Figure\u00a03). Some researchers believe that this infrastructure helped protect the Romans from epidemics of waterborne illnesses.<\/p>\n<div style=\"width: 1311px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153414\/OSC_Microbio_01_01_cloaca.jpg\" alt=\"Figure\u00a0a is a map of a city containing a stadium, forum, and other structures. Running through the center of the city is a red line. Figure\u00a0b is a photograph of a corner of a room. There is a trough between the walls and the floor. This trough is covered with stone benches that have large holes (as for a toilet) in the bench. The holes span the top and front of the bench. There are six holes visible in the bench that runs along one side of the image and two more in the bench along the other side. The image does not show the entire room so there are likely more available spots in this room.\" width=\"1301\" height=\"1272\" \/><\/p>\n<p class=\"wp-caption-text\">Figure\u00a03. (a) The <em>Cloaca Maxima<\/em>, or &#8220;Greatest Sewer&#8221; (shown in red), ran through ancient Rome. It was an engineering marvel that carried waste away from the city and into the river Tiber. (b) These ancient latrines emptied into the <em>Cloaca Maxima<\/em>.<\/p>\n<\/div>\n<p>Even before the invention of the microscope, some doctors, philosophers, and scientists made great strides in understanding the invisible forces\u2014what we now know as microbes\u2014that can cause infection, disease, and death.<\/p>\n<p>The Greek physician Hippocrates (460\u2013370 BC) is considered the &#8220;father of Western medicine&#8221; (Figure\u00a04a). Unlike many of his ancestors and contemporaries, he dismissed the idea that disease was caused by supernatural forces. Instead, he posited that diseases had natural causes from within patients or their environments. Hippocrates and his heirs are believed to have written the <em>Hippocratic Corpus<\/em>, a collection of texts that make up some of the oldest surviving medical books.<a class=\"footnote\" title=\"G. Pappas et al. &quot;Insights Into Infectious Disease in the Era of Hippocrates.&quot; International Journal of Infectious Diseases 12 (2008) 4:347\u2013350. doi: http:\/\/dx.doi.org\/10.1016\/j.ijid.2007.11.003.\" id=\"return-footnote-60-5\" href=\"#footnote-60-5\" aria-label=\"Footnote 5\"><sup class=\"footnote\">[5]<\/sup><\/a>\u00a0Hippocrates is also often credited as the author of the Hippocratic Oath, taken by new physicians to pledge their dedication to diagnosing and treating patients without causing harm.<\/p>\n<p>While Hippocrates is considered the father of Western medicine, the Greek philosopher and historian Thucydides (460\u2013395 BC) is considered the father of scientific history because he advocated for evidence-based analysis of cause-and-effect reasoning (Figure\u00a04b). Among his most important contributions are his observations regarding the Athenian plague that killed one-third of the population of Athens between 430 and 410 BC. Having survived the epidemic himself, Thucydides made the important observation that survivors did not get re-infected with the disease, even when taking care of actively sick people.<a class=\"footnote\" title=\"Thucydides. The History of the Peloponnesian War. The Second Book. 431 BC. Translated by Richard Crawley. http:\/\/classics.mit.edu\/Thucydides\/pelopwar.2.second.html.\" id=\"return-footnote-60-6\" href=\"#footnote-60-6\" aria-label=\"Footnote 6\"><sup class=\"footnote\">[6]<\/sup><\/a>\u00a0This observation shows an early understanding of the concept of immunity.<\/p>\n<p>Marcus Terentius Varro (116\u201327 BC) was a prolific Roman writer who was one of the first people to propose the concept that things we cannot see (what we now call microorganisms) can cause disease (Figure\u00a04c). In <em>Res Rusticae<\/em> (<em>On Farming<\/em>), published in 36 BC, he said that<\/p>\n<blockquote><p>precautions must also be taken in neighborhood swamps . . . because certain minute creatures [<em>animalia minuta<\/em>] grow there which cannot be seen by the eye, which float in the air and enter the body through the mouth and nose and there cause serious diseases.<a class=\"footnote\" title=\"Plinio Prioreschi. A History of Medicine: Roman Medicine. Lewiston, NY: Edwin Mellen Press, 1998: p. 215.\" id=\"return-footnote-60-7\" href=\"#footnote-60-7\" aria-label=\"Footnote 7\"><sup class=\"footnote\">[7]<\/sup><\/a><\/p><\/blockquote>\n<div style=\"width: 1111px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153418\/OSC_Microbio_01_01_ancients.jpg\" alt=\"Figure\u00a0a is a drawing of a bust of Hippocrates. Figure\u00a0b is a photo of a sculpture of Thucydides\u2019s head. Figure\u00a0c is a photo of a sculpture of Marcus Terentius Varro.\" width=\"1101\" height=\"518\" \/><\/p>\n<p class=\"wp-caption-text\">Figure\u00a04. (a) Hippocrates, the &#8220;father of Western medicine,&#8221; believed that diseases had natural, not supernatural, causes. (b) The historian Thucydides observed that survivors of the Athenian plague were subsequently immune to the infection. (c) Marcus Terentius Varro proposed that disease could be caused by &#8220;certain minute creatures . . . which cannot be seen by the eye.&#8221; (credit c: modification of work by Alessandro Antonelli)<\/p>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Think about It<\/h3>\n<ul>\n<li>Give two examples of foods that have historically been produced by humans with the aid of microbes.<\/li>\n<li>Explain how historical understandings of disease contributed to attempts to treat and contain disease.<\/li>\n<\/ul>\n<\/div>\n<h2>The Birth of Microbiology<\/h2>\n<p>While the ancients may have suspected the existence of invisible &#8220;minute creatures,&#8221; it wasn\u2019t until the invention of the microscope that their existence was definitively confirmed. While it is unclear who exactly invented the microscope, a Dutch cloth merchant named Antonie van Leeuwenhoek (1632\u20131723) was the first to develop a lens powerful enough to view microbes. In 1675, using a simple but powerful microscope, Leeuwenhoek was able to observe single-celled organisms, which he described as &#8220;animalcules&#8221; or &#8220;wee little beasties,&#8221; swimming in a drop of rain water. From his drawings of these little organisms, we now know he was looking at bacteria and protists. (We will explore Leeuwenhoek\u2019s contributions to microscopy further in <a class=\"target-chapter\" href=\".\/chapter\/introduction-to-how-we-see-the-invisible-world\/\">How We See the Invisible World<\/a>.)<\/p>\n<p>Nearly 200 years after van Leeuwenhoek got his first glimpse of microbes, the &#8220;Golden Age of Microbiology&#8221; spawned a host of new discoveries between 1857 and 1914. Two famous microbiologists, Louis Pasteur and Robert Koch, were especially active in advancing our understanding of the unseen world of microbes (Figure\u00a05). Pasteur, a French chemist, showed that individual microbial strains had unique properties and demonstrated that fermentation is caused by microorganisms. He also invented pasteurization, a process used to kill microorganisms responsible for spoilage, and developed vaccines for the treatment of diseases, including rabies, in animals and humans. Koch, a German physician, was the first to demonstrate the connection between a single, isolated microbe and a known human disease. For example, he discovered the bacteria that cause anthrax (<em>Bacillus anthracis<\/em>), cholera (<em>Vibrio cholera<\/em>), and tuberculosis (<em>Mycobacterium tuberculosis<\/em>).<a class=\"footnote\" title=\"S.M. Blevins and M.S. Bronze. &quot;Robert Koch and the \u2018Golden Age\u2019 of Bacteriology.&quot; International Journal of Infectious Diseases. 14 no. 9 (2010): e744-e751. doi:10.1016\/j.ijid.2009.12.003.\" id=\"return-footnote-60-8\" href=\"#footnote-60-8\" aria-label=\"Footnote 8\"><sup class=\"footnote\">[8]<\/sup><\/a> We will discuss these famous microbiologists, and others, in later chapters.<\/p>\n<div style=\"width: 1110px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153421\/OSC_Microbio_01_01_PastKoch.jpg\" alt=\"Figure\u00a0a is a drawing of Louis Pasteur in his lab. Figure\u00a0b is a photograph of Robert Koch.\" width=\"1100\" height=\"682\" \/><\/p>\n<p class=\"wp-caption-text\">Figure\u00a05. (a) Louis Pasteur (1822\u20131895) is credited with numerous innovations that advanced the fields of microbiology and immunology. (b) Robert Koch (1843\u20131910) identified the specific microbes that cause anthrax, cholera, and tuberculosis.<\/p>\n<\/div>\n<p>As microbiology has developed, it has allowed the broader discipline of biology to grow and flourish in previously unimagined ways. Much of what we know about human cells comes from our understanding of microbes, and many of the tools we use today to study cells and their genetics derive from work with microbes.<\/p>\n<div class=\"textbox key-takeaways\">\n<h3>Think about It<\/h3>\n<p>How did the discovery of microbes change human understanding of disease?<\/p>\n<\/div>\n<div class=\"textbox shaded\">\n<h3>Microbiology Toolbox<\/h3>\n<p>Because individual microbes are generally too small to be seen with the naked eye, the science of microbiology is dependent on technology that can artificially enhance the capacity of our natural senses of perception. Early microbiologists like Pasteur and Koch had fewer tools at their disposal than are found in modern laboratories, making their discoveries and innovations that much more impressive. Later chapters of this text will explore many applications of technology in depth, but for now, here is a brief overview of some of the fundamental tools of the microbiology lab.<\/p>\n<ul>\n<li><strong>Microscopes<\/strong> produce magnified images of microorganisms, human cells and tissues, and many other types of specimens too small to be observed with the naked eye.<\/li>\n<li><strong>Stains and dyes<\/strong> are used to add color to microbes so they can be better observed under a microscope. Some dyes can be used on living microbes, whereas others require that the specimens be fixed with chemicals or heat before staining. Some stains only work on certain types of microbes because of differences in their cellular chemical composition.<\/li>\n<li><strong>Growth media<\/strong> are used to grow microorganisms in a lab setting. Some media are liquids; others are more solid or gel-like. A growth medium provides nutrients, including water, various salts, a source of carbon (like glucose), and a source of nitrogen and amino acids (like yeast extract) so microorganisms can grow and reproduce. Ingredients in a growth medium can be modified to grow unique types of microorganisms.<\/li>\n<li><strong>A Petri dish<\/strong> is a flat-lidded dish that is typically 10\u201311 centimeters (cm) in diameter and 1\u20131.5 cm high. Petri dishes made out of either plastic or glass are used to hold growth media (Figure\u00a06a).<\/li>\n<li><strong>Test tubes<\/strong> are cylindrical plastic or glass tubes with rounded bottoms and open tops. They can be used to grow microbes in broth, or semisolid or solid growth media.<\/li>\n<li>A <strong>Bunsen burner<\/strong> is a metal apparatus that creates a flame that can be used to sterilize pieces of equipment. A rubber tube carries gas (fuel) to the burner. In many labs, Bunsen burners are being phased out in favor of infrared <strong>microincinerators<\/strong>, which serve a similar purpose without the safety risks of an open flame.<\/li>\n<li>An <strong>inoculation loop<\/strong> is a handheld tool that ends in a small wire loop (Figure\u00a06b). The loop can be used to streak microorganisms on agar in a Petri dish or to transfer them from one test tube to another. Before each use, the inoculation loop must be sterilized so cultures do not become contaminated.<\/li>\n<\/ul>\n<div style=\"width: 1110px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1094\/2016\/11\/03153425\/OSC_Microbio_01_01_Petri.jpg\" alt=\"Figure\u00a0a is a photograph of a round disk streaked with lines. The thickest lines go back and forth along an area spanning one fifth of the plate. The next fifth of the plate also has thick lines. The next fifth of the plate has thinner lines that are made of tiny dots. The final fifth of the pate only has large dots. Figure\u00a0b shows a hand holding a metal rod that is the diameter of a pretzel stick; projecting from tis is a thick wire that is formed into a loop at the end.\" width=\"1100\" height=\"499\" \/><\/p>\n<p class=\"wp-caption-text\">Figure\u00a06. (a) This Petri dish filled with agar has been streaked with <em>Legionella<\/em>, the bacterium responsible for causing Legionnaire\u2019s disease. (b) An inoculation loop like this one can be used to streak bacteria on agar in a Petri dish. (credit a: modification of work by Centers for Disease Control and Prevention; credit b: modification of work by Jeffrey M. Vinocur)<\/p>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Key Concepts and Summary<\/h3>\n<ul>\n<li><strong>Microorganisms<\/strong> (or <strong>microbes<\/strong>) are living organisms that are generally too small to be seen without a microscope.<\/li>\n<li>Throughout history, humans have used microbes to make fermented foods such as beer, bread, cheese, and wine.<\/li>\n<li>Long before the invention of the microscope, some people theorized that infection and disease were spread by living things that were too small to be seen. They also correctly intuited certain principles regarding the spread of disease and immunity.<\/li>\n<li>Antonie van Leeuwenhoek, using a microscope, was the first to actually describe observations of bacteria, in 1675.<\/li>\n<li>During the Golden Age of Microbiology (1857\u20131914), microbiologists, including Louis Pasteur and Robert Koch, discovered many new connections between the fields of microbiology and medicine.<\/li>\n<\/ul>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Multiple Choice<\/h3>\n<p>Which of the following foods is NOT made by fermentation?<\/p>\n<ol style=\"list-style-type: lower-alpha\">\n<li>beer<\/li>\n<li>bread<\/li>\n<li>cheese<\/li>\n<li>orange juice<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q809245\">Show Answer<\/span><\/p>\n<div id=\"q809245\" class=\"hidden-answer\" style=\"display: none\">Answer d. Orange juice is not made with fermentation.<\/div>\n<\/div>\n<p>Who is considered the &#8220;father of Western medicine&#8221;?<\/p>\n<ol style=\"list-style-type: lower-alpha\">\n<li>Marcus Terentius Varro<\/li>\n<li>Thucydides<\/li>\n<li>Antonie van Leeuwenhoek<\/li>\n<li>Hippocrates<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q961496\">Show Answer<\/span><\/p>\n<div id=\"q961496\" class=\"hidden-answer\" style=\"display: none\">Answer d. Hippocrates is considered to be the father of Western medicine.<\/div>\n<\/div>\n<p>Who was the first to observe &#8220;animalcules&#8221; under the microscope?<\/p>\n<ol style=\"list-style-type: lower-alpha\">\n<li>Antonie van Leeuwenhoek<\/li>\n<li>\u00d6tzi the Iceman<\/li>\n<li>Marcus Terentius Varro<\/li>\n<li>Robert Koch<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q774028\">Show Answer<\/span><\/p>\n<div id=\"q774028\" class=\"hidden-answer\" style=\"display: none\">Answer a. Antonie van Leeuwenhoek was the first to observe &#8220;animalcules.&#8221;<\/div>\n<\/div>\n<p>Who proposed that swamps might harbor tiny, disease-causing animals too small to see?<\/p>\n<ol style=\"list-style-type: lower-alpha\">\n<li>Thucydides<\/li>\n<li>Marcus Terentius Varro<\/li>\n<li>Hippocrates<\/li>\n<li>Louis Pasteur<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q769727\">Show Answer<\/span><\/p>\n<div id=\"q769727\" class=\"hidden-answer\" style=\"display: none\">Answer b. Marcus Terentius Varro proposed that swamps might harbor tiny, disease-causing animals too small to see.<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Fill in the Blank<\/h3>\n<p>Thucydides is known as the father of _______________.<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q537429\">Show Answer<\/span><\/p>\n<div id=\"q537429\" class=\"hidden-answer\" style=\"display: none\">Thucydides is known as the father of <strong>scientific history<\/strong>. <\/div>\n<\/div>\n<p>Researchers think that \u00d6tzi the Iceman may have been infected with _____ disease.<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q494540\">Show Answer<\/span><\/p>\n<div id=\"q494540\" class=\"hidden-answer\" style=\"display: none\">Researchers think that \u00d6tzi the Iceman may have been infected with <strong>Lyme<\/strong> disease.<\/div>\n<\/div>\n<p>The process by which microbes turn grape juice into wine is called _______________.<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q530716\">Show Answer<\/span><\/p>\n<div id=\"q530716\" class=\"hidden-answer\" style=\"display: none\">The process by which microbes turn grape juice into wine is called <strong>fermentation<\/strong>.<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Think about It<\/h3>\n<ol>\n<li>What did Thucydides learn by observing the Athenian plague?<\/li>\n<li>Why was the invention of the microscope important for microbiology?<\/li>\n<li>What are some ways people use microbes?<\/li>\n<li>Explain how the discovery of fermented foods likely benefited our ancestors.<\/li>\n<li>What evidence would you use to support this statement: Ancient people thought that disease was transmitted by things they could not see.<\/li>\n<\/ol>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-60\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>OpenStax Microbiology. <strong>Provided by<\/strong>: OpenStax CNX. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/e42bd376-624b-4c0f-972f-e0c57998e765@4.2\">http:\/\/cnx.org\/contents\/e42bd376-624b-4c0f-972f-e0c57998e765@4.2<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Download for free at http:\/\/cnx.org\/contents\/e42bd376-624b-4c0f-972f-e0c57998e765@4.2<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section><hr class=\"before-footnotes clear\" \/><div class=\"footnotes\"><ol><li id=\"footnote-60-1\">P.E. McGovern et al. \"Fermented Beverages of Pre- and Proto-Historic China.\" <em>Proceedings of the National Academy of Sciences of the United States of America<\/em> 1 no. 51 (2004):17593\u201317598. doi:10.1073\/pnas.0407921102. <a href=\"#return-footnote-60-1\" class=\"return-footnote\" aria-label=\"Return to footnote 1\">&crarr;<\/a><\/li><li id=\"footnote-60-2\">A. Keller et al. \"New Insights into the Tyrolean Iceman's Origin and Phenotype as Inferred by Whole-Genome Sequencing.\" <em>Nature Communications<\/em>, 3 (2012): 698. doi:10.1038\/ncomms1701. <a href=\"#return-footnote-60-2\" class=\"return-footnote\" aria-label=\"Return to footnote 2\">&crarr;<\/a><\/li><li id=\"footnote-60-3\">L. Capasso. \"5300 Years Ago, the Ice Man Used Natural Laxatives and Antibiotics.\" <em>The Lancet<\/em>, 352 (1998) 9143: 1864. doi: 10.1016\/s0140-6736(05)79939-6. <a href=\"#return-footnote-60-3\" class=\"return-footnote\" aria-label=\"Return to footnote 3\">&crarr;<\/a><\/li><li id=\"footnote-60-4\">L. Capasso, L. \"5300 Years Ago, the Ice Man Used Natural Laxatives and Antibiotics.\" <em>The Lancet<\/em>, 352 no. 9143 (1998): 1864. doi: 10.1016\/s0140-6736(05)79939-6. <a href=\"#return-footnote-60-4\" class=\"return-footnote\" aria-label=\"Return to footnote 4\">&crarr;<\/a><\/li><li id=\"footnote-60-5\">G. Pappas et al. \"Insights Into Infectious Disease in the Era of Hippocrates.\" <em>International Journal of Infectious Diseases<\/em> 12 (2008) 4:347\u2013350. doi: http:\/\/dx.doi.org\/10.1016\/j.ijid.2007.11.003. <a href=\"#return-footnote-60-5\" class=\"return-footnote\" aria-label=\"Return to footnote 5\">&crarr;<\/a><\/li><li id=\"footnote-60-6\">Thucydides. <em>The History of the Peloponnesian War. The Second Book<\/em>. 431 BC. Translated by Richard Crawley. http:\/\/classics.mit.edu\/Thucydides\/pelopwar.2.second.html. <a href=\"#return-footnote-60-6\" class=\"return-footnote\" aria-label=\"Return to footnote 6\">&crarr;<\/a><\/li><li id=\"footnote-60-7\">Plinio Prioreschi. <em>A History of Medicine: Roman Medicine<\/em>. Lewiston, NY: Edwin Mellen Press, 1998: p. 215. <a href=\"#return-footnote-60-7\" class=\"return-footnote\" aria-label=\"Return to footnote 7\">&crarr;<\/a><\/li><li id=\"footnote-60-8\">S.M. Blevins and M.S. Bronze. \"Robert Koch and the \u2018Golden Age\u2019 of Bacteriology.\" <em>International Journal of Infectious Diseases<\/em>. 14 no. 9 (2010): e744-e751. doi:10.1016\/j.ijid.2009.12.003. <a href=\"#return-footnote-60-8\" class=\"return-footnote\" aria-label=\"Return to footnote 8\">&crarr;<\/a><\/li><\/ol><\/div>","protected":false},"author":17,"menu_order":2,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"OpenStax Microbiology\",\"author\":\"\",\"organization\":\"OpenStax CNX\",\"url\":\"http:\/\/cnx.org\/contents\/e42bd376-624b-4c0f-972f-e0c57998e765@4.2\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at http:\/\/cnx.org\/contents\/e42bd376-624b-4c0f-972f-e0c57998e765@4.2\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-60","chapter","type-chapter","status-publish","hentry"],"part":51,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/pressbooks\/v2\/chapters\/60","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":10,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/pressbooks\/v2\/chapters\/60\/revisions"}],"predecessor-version":[{"id":2131,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/pressbooks\/v2\/chapters\/60\/revisions\/2131"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/pressbooks\/v2\/parts\/51"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/pressbooks\/v2\/chapters\/60\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/wp\/v2\/media?parent=60"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/pressbooks\/v2\/chapter-type?post=60"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/wp\/v2\/contributor?post=60"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-microbiology\/wp-json\/wp\/v2\/license?post=60"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}