“I Contain Multitudes” by Ed Yong explains in 355 pages the amazing benefit that microbes have on earth and in us. This 2016 non-fiction novel informs his readers about the world of microbes and the symbiotic relations they have with their host through a variety of examples as the author dives into the world of microbes. Ed Yong is an award winning science writer that breaks down this new small world in easy to digest layman examples to educate readers the importance of these small organisms with their host. He has traveled to many institutions and spoke the experts of various fields in the world of microbiology to understand the tremendous impact that microbes have. He mainly goes into the world of animals and their relationship with microbes, but he wonderfully connects these examples to help us understand the future of probiotics and disease in humans.As Yong goes into his examples, it is clear that the microbial world is in a delicate balance with our reality. Although he does focuses on animal, mainly humans and their relationship with microbes, he does points out that Jack Gilbert and Josh Neufeld stated if plants were don’t have any microbes, they surely will fail and can lead to societal collapse because there food chain would fail. Plants depends on microbes to fix nitrogen or give it key nutrients to help the plants flourish. This example he uses early on in the book really set the tone for the rest of the examples and how far a single microbe influence can have a snowball effect on us.Ed starts the reader’s journey with Baba, a pangolin at the San Diego Zoo with Baba’s keeper swabbing the Baba’s body to understand his microbiome. Ed lays out the foundation to the rest of the book by explaining basic key terms and concepts of the diversity of microbes on the body. As the book progress, Ed goes into the importance of microbes to humans. He states that if animals were sterile, free of any microbes, they would die. For example, if sap-sucking bugs lack their bacteria in their gut, they would parish because they wouldn’t be able to get all the nutrients they need without those important bacteria.Like Baba, humans have their own unique microbiome throughout their body, like the how the skin microflora differs from the gut microflora. This diversity on the human body is so interesting, that even the microflora of the right hand would be different than the microflora of the left hand. This diversity is also unique from person to person.The journey of a human obtaining their own unique microbiome starts at birth. In the womb, the fetus is completely sterile, but during birth, the baby obtains its first microbes can be traced back to their mom. He does goes into how the differences of birthing method, vaginal and cesarean section affects a child’s first microbes. These microbes can affect the child’s immune responses in the future. Even having a pet or an older sibling in the development of a child can may reduce the possibility of allergies of the child as a result of constant exposure at a young age to a variety of microbes from diverse locations. This trains the immune system at an early age to help fight infections later in life.It is emphasized that a mother is the biggest player in shaping the child’s microbiome. Not just from the birthing method, but also the role of breast milk. Yong divulges in the amazing properties of break milk for babies on how it plays a huge role on a babies gut microbiota. Breast milk is one of humans first prebiotic for a baby, since it not only nourishes and protect the immune system of the baby, but provides nutrients to the child’s first set of bacteria, L. infantilis in their gut.Yong even states that the gut microbiome can also affect behavior. He starts his example with lab mice, and if pregnant mother with infection during pregnancy, it can have healthy offspring that can have behavioral abnormalities in adulthood such as repetitive behaviors and social aversion, which is similar to the humans conditions of autism and schizophrenia. When looking at the gut microbiota diversity of a mice with such quirks to a normal mouse, there is a difference in the variety, even when everything is the same, such as environment and nutrition.This behavior in mice is relates to behavior in autistic individuals, although it is stated that mice don’t have autism since autism, according to Emily Willingham, is shaped by society and what seems to be normal. When gut microbes from autistic children were transplanted into the gut of healthy mice, the mice’s behavior did change by repetitive burying of a marble and low frequency of squeaks, which could be related to autistic behaviors of children. Yong mentions that that the gut microbe are partially responsible for such behaviors in autistic children, but it cannot be the sole reason.Fascinatingly, germ free mice that lacked a gut microbiome had behavior differences of their normal microbiota counterpart, these mice were more timid. When introduced to the bacteria commonly found in yoghurt and dairy products, Lactobacillus rhamnosus, specifically the strain JB-1 to their gut, the mice were able to overcome anxiety through the same tests that were made to test psychiatric drugs. Apparently, the strain JB-1 acted like a low dose of anti-anxiety and antidepressants, according to Cyan from the University of Cork. The researched looked into the brains of the mice of JB-1 and showed that brains response to GABA changed with the strain. The suspected that the nerve that that carries signal from the brain to gut aided JB-1 in the influence of the improved behavior in the mice. Yong informs reader of current research that correlated the behavior to the gut microbiota, demonstrated that there is more than meets the eye of the microflora animals.Not only does the book go into detail of the symbiosis humans and their microbes, it proved examples of how microorganisms help with survival of the host, like the illuminating Vibrio fischeri and the Hawaiian bobtail squid. When the Hawaiian bobtail squid hatches from their egg, it is born without V. fischeri. Interestingly enough, the bobtail squid has immature crypts which houses these bacteria. When V. fischeri goes to colonize the squid. Once these bacteria colonize the squid, it start to mature the remaining organs to help it survive in their environment. It take more than just a few of the V. fischeri to help the Hawaiian bobtail squid survive. Once the bacteria reached a certain threshold of one turn on their bioluminescent to hide the bobtail squid’s shadow in the water and also produce antimicrobial properties to it can reduce competition by making it impossible for other microbes to occupy the bobtail. In exchange for helping the bobtail squid V. fischeri gains protection and a constant supply of nutrients.The symbiosis of a microorganism and its host can be an indicator of the health of the host and environment, such as dying coral reefs on Christmas Island. The dying reefs are a prime example of a delicate balance of the symbiosis of microbes, because a reason for these reefs to dye is algae. The rise of algae is a result of the disruption of the food chain, such as the decrease of sharks. Sharks host an abundance of algae, if they are gone, the algae population stays in the water as wells are the production of dissolved organic carbon. This dissolved organic carbon will allow the microbe populations toe exponentially increase; therefore, consuming all the surrounding oxygen, essentially chocking the corals.Usually there are 10 percent of the local microbe species in coral are pathogenic and cause disease because the normal coral microflora keeps the population of microbes in check. Around Christmas Island it is around 50 percent because of the abundance of nutrients from the algae. As coral die, it makes room for more of this algae to grow, which leads to a never ending cycle of dying coral and flourishing microbial community and algae.As Yong enlightens readers of the benefit of microbes in the world, he leads us to microbes place in medical field. Like his previous example of the how microbes can affect behavior, he leads us to thinking about the potential uses of microbes in treating diseases or maximizing the effect of medicine. For example, digoxin has been used to treat patients with hearts that are failing, but it the patients has Eggerthella lenta in their gut microbiome, digoxin will not work because the bacteria converts the drug into an inactive form. This isn’t the only drug and microbe pair that affect treatment. Yong brings up fecal transplant or a more refined and cleaner version to be the future of treatments, not just in behavior but in all sorts of treatments to help reduce symptoms or treat disease. Even brings up that inside the hospital is riddling with a high concentrations pathogenic microbes, but if a window is just opened to allow the outside microbes to come in and occupy space in the hospital. These outside microbes in the environment will push out and decrease the pathogenic microbial population.Readers do not need to come from a science background to read and thoroughly understand this book, because Ed Yong wonderfully explains the purpose of each example and how it correlated back the balance of a delicate symbiosis of the microbe and its host. This book is amazing to for readers of all backgrounds, but I would recommend this book to mothers, physicians and health fanatics since Ed Yong displays the importance of microbes to the positive health of the human body and the environment. A disruption of microbes can cause huge impact on the host or environment, which can allow us to pinpoint the cause of the disruption. Microbes and their effects are great indicator of the health of where it is occupying. Essentially, microbes are not as evil as we have been taught to think.The issue with Ed Yong’s book is the fact he didn’t mention quorum sensing one in the book, because that would help the reader understand how microbes effect their own population or the community they live with. Also, Ed Yong jumped around a lot in examples, I felt like he could have separated examples by relevance. Personally, I would have started his examples with the symbiosis of the bugs then to talk about the corals the impact of environments. Then use antibiotic resistance as a transition from animals to humans, then go into behaviors affected by microbes. He could have concluded with fecal matter transplant and using microbes as treatments and then ended with the research of tracking a building’s, new or old microbiome.It took until the end to understand the purpose of this book, because Yong starts out with going on this adventure to understand the world of microbes without giving a reason. It later chapters, everything comes together on why this subject is important. The future of medicine and treatments could possibly lie in the hands of the microscopic organisms. Even understanding the environmental health can be indicated by the concentration or shift in diversity of microbes. He mentions that probiotics would be uniquely prescribed to patients with a nutrient regime to either enhance to effectiveness of medicine or to be the medicine itself to help with certain symptoms or diseases. Over all, Ed Yong did an amazing job on informing readers on the world of microbes in a way that a variety of backgrounds could understand.