第1段

Microbes, most of them bacteria, have populated this planet since long before animal life developed and they will outlive us. Invisible to the naked eye, they are ubiquitous. They inhabit the soil, air, rocks and water and are present within every form of life, from seaweed and coral to dogs and humans. And, as Yong explains in his utterly absorbing and hugely important book, we mess with them at our peril.

第2段

Every species has its own colony of microbes, called a ‘microbiome’, and these microbes vary not only between species but also between individuals and within different parts of each individual. What is amazing is that while the number of human cells in the average person is about 30 trillion, the number of microbial ones is higher – about 39 trillion. At best, Yong informs us, we are only 50 per cent human. Indeed, some scientists even suggest we should think of each species and its microbes as a single unit, dubbed a ‘holobiont’.

第3段

In each human there are microbes that live only in the stomach, the mouth or the armpit and by and large they do so peacefully. So ‘bad’ microbes are just microbes out of context. Microbes that sit contentedly in the human gut (where there are more microbes than there are stars in the galaxy) can become deadly if they find their way into the bloodstream.  These communities are constantly changing too. The right hand shares just one sixth of its microbes with the left hand. And, of course, we are surrounded by microbes. Every time we eat, we swallow a million microbes in each gram of food; we are continually swapping microbes with other humans, pets and the world at large…

第4段

It’s a fascinating topic and Yong, a young British science journalist, is an extraordinarily adept guide. Writing with lightness and panache, he has a knack of explaining complex science in terms that are both easy to understand and totally enthralling. Yong is on a mission. Leading us gently by the hand, he takes us into the world of microbes – a bizarre, alien planet – in a bid to persuade us to love them as much as he does. By the end, we do.

第5段

For most of human history we had no idea that microbes existed. The first man to see these extraordinarily potent creatures was a Dutch lens-maker called Antony van Leeuwenhoek in the 1670s. Using microscopes of his own design that could magnify up to 270 times, he examined a drop of water from a nearby lake and found it teeming with tiny creatures he called ‘animalcules’. It wasn’t until nearly two hundred years later that the research of French biologist Louis Pasteur indicated that some microbes caused disease. It was Pasteur’s ‘germ theory’ that gave bacteria the poor image that endures today.

第6段

Yong’s book is in many ways a plea for microbial tolerance, pointing out that while fewer than one hundred species of bacteria bring disease, many thousands more play a vital role in maintaining our health. The book also acknowledges that our attitude towards bacteria is no a simple one. We tend to see the dangers posed by bacteria, yet at the same time we are sold yoghurts and drinks that supposedly nurture “friendly’ bacteria. In reality, says Yong, bacteria should not be viewed as either friends or foes, villains or heroes. Instead we should realise we have a symbiotic relationship, that can be mutually beneficial or mutually destructive.

第7段

What then do these millions of organisms do? The answer is pretty much everything. New research is now unravelling the ways in which bacteria aid digestion, regulate our immune systems, eliminate toxins, produce vitamins, affect our behaviour and even combat obesity. ‘They actually help us become who we are,’ says Yong. But we are facing a growing problem. Our obsession with hygiene, our overuse of antibiotics and our unhealthy, low-fibre diets are disrupting the bacterial balance and may be responsible for soaring rates of allergies and immune problems, such as inflammatory bowel disease (IBD).

第8段

The most recent research actually turns accepted norms upside down. For example, there are studies indicating that the excessive use of household detergents and antibacterial products actually destroys the microbes that normally keep the more dangerous germs at bay. Other studies show that keeping a dog as a pet gives children early exposure to a diverse range of bacteria which may help protect them against allergies later.

第9段

The readers of Yong’s book must be prepared for a decidedly unglamorous world. Among the less appealing case studies is one about a fungus that is wiping out entire populations of frogs and that can be halted by a rare microbial bacterium. Another is about squid that carry luminescent bacteria that protect them against predators. However, if you can overcome your distaste for some of the investigations, the reasons for Yong’s enthusiasm become clear. The microbial world is a place of wonder. Already, in an attempt to stop mosquitoes spreading dengue fever – a disease that infects 400 million people a year – mosquitoes are being loaded with a bacterium to block the disease. In the future, our ability to manipulate microbes means we could construct buildings with useful microbes built into their walls to fight off infections. Just imagine a neonatal hospital ward coated in a specially mixed cocktail of microbes so that babies get the best start in life.

微生物，其中大部分是细菌，自动物生命出现之前就在这个星球上繁衍生息，它们将比我们更长寿。肉眼无法看见它们，它们无处不在。它们栖息在土壤、空气、岩石和水中，并存在于每种生物中，从海藻和珊瑚到狗和人类。正如Yong在他引人入胜且极其重要的著作中所解释的那样，我们对它们的干预是危险的。

每个物种都有自己的微生物群落，称为“微生物组”，这些微生物不仅在物种之间有所不同，而且在个体的不同部分之间也有所不同。令人惊奇的是，虽然平均每个人体内的人类细胞数约为30万亿个，但微生物细胞的数量更高，约为39万亿个。Yong告诉我们，最多我们只有50%是人类。事实上，一些科学家甚至建议我们将每个物种及其微生物视为一个整体，称为“全生物”。

每个人体内都有只生活在胃、口腔或腋窝的微生物，它们通常和平共处。因此，“有害”微生物只是失去环境的微生物。如果这些安居在人类肠道中的微生物（肠道中的微生物数量比银河系中的恒星还多）进入血液中，它们就会变得致命。这些微生物群落也在不断变化。右手与左手只共享了六分之一的微生物。当然，我们周围都是微生物。每当我们进食时，每克食物中就会吞下一百万个微生物；我们不断与其他人类、宠物和整个世界交换微生物…

这是一个迷人的话题，年轻的英国科学记者Yong是一位非常熟练的向导。他以轻松优雅的笔调写作，善于用易于理解和非常吸引人的方式解释复杂的科学。Yong有一个使命。他轻轻地带领我们进入微生物的世界——一个奇异、外星的星球——试图说服我们像他一样热爱它们。最后，我们确实爱上了微生物。

在人类历史的大部分时间里，我们不知道微生物的存在。第一个看到这些异常强大生物的人是17世纪的荷兰镜片制造商安东尼·凡·李文霍克。他使用自己设计的能够放大270倍的显微镜，观察了附近湖泊的一滴水，发现里面有很多他称之为“动物幼虫”的微小生物。直到近两百年后，法国生物学家路易·巴斯德的研究表明，一些微生物会引起疾病。正是巴斯德的“病原体理论”使细菌获得了今天持续存在的负面形象。

Yong的书在很多方面都是对微生物的宽容的呼吁，指出虽然只有不到一百种细菌会引发疾病，但还有成千上万种细菌在维持我们的健康方面起着至关重要的作用。该书还承认我们对细菌的态度并不简单。我们倾向于看到细菌带来的危险，但同时我们也会购买声称滋养“友善”细菌的酸奶和饮料。实际上，Yong说，我们不应该将细菌视为朋友或敌人、恶棍或英雄。相反，我们应该意识到我们有一种共生关系，这种关系可以互利互惠，也可以互相破坏。

那么，这些数百万个生物到底做些什么呢？答案几乎是一切。新的研究正在揭示细菌在帮助消化、调节免疫系统、清除毒素、产生维生素、影响行为甚至对抗肥胖方面的作用。Yong说：“它们实际上帮助我们成为我们自己。”但我们面临着一个日益严重的问题。我们对卫生的过度追求、过度使用抗生素以及不健康、低纤维的饮食正在破坏细菌平衡，可能导致过敏和免疫问题的激增，例如炎症性肠病（IBD）。

最新的研究实际上颠覆了公认的规范。例如，有研究表明，过度使用家庭清洁剂和抗菌产品实际上会破坏通常阻止更危险的细菌的微生物。其他研究表明，养狗会让儿童早期接触到多样性的细菌，这可能有助于保护他们免受过敏症的侵害。

Yong的书的读者必须准备好进入一个相当不吸引人的世界。在其中不太吸引人的案例研究中，有一个关于正在消灭整个青蛙种群的真菌，可以被一种罕见的微生物细菌阻止。另一个案例是关于携带发光细菌以保护自己免受捕食者侵害的乌贼。然而，如果你能克服对一些研究的厌恶，就能够理解Yong的热情的原因。微生物世界是一个奇妙的地方。为了阻止蚊子传播每年感染4亿人的登革热，人们正在将蚊子注入一种能够阻止该病的细菌。在未来，我们操纵微生物的能力意味着我们可以在建筑物的墙壁中嵌入有益微生物来抵御感染。想象一下，一个新生儿医院病房涂上一种特殊混合的微生物鸡尾酒，让婴儿在生命的起点得到最好的开始。