They are, in short, a big part of us. 总而言之，细菌是我们的一个很大的组成部分。

From the bacteria's point of view, of course, we are a rather small part of them. 当然，从细菌的角度来看，我们只是它们的一个很小的组成部分。

Because we humans are big and clever enough to produce and utilize antibiotics and disinfectants, 我们人类个儿大，又聪明，能生产使用抗生素和杀菌剂，

it is easy to convince ourselves that we have banished bacteria to the fringes of existence. 因此很容易认为自己快要把细菌灭绝了。

Don't you believe it. 别相信那种看法。

Bacteria may not build cities or have interesting social lives, but they will be here when the Sun explodes. 细菌也许不会建立城市，不会过有意思的社交生活，但它们到太阳爆炸的时候还会在这里。

This is their planet, and we are on it only because they allow us to be. 这是它们的行星，我们之所以在这里，是因为它们允许我们在这里。

Bacteria, never forget, got along for billions of years without us. 千万不要忘记，细菌已经在没有我们的情况下生活了几十亿年。

We couldn't survive a day without them. 而要是没有它们，我们一天也活不下去。

They process our wastes and make them usable again; without their diligent munching nothing would rot. 它们处理我们的废料，使其重新有用；没有它们的辛勤咀嚼，什么也不会腐烂。

They purify our water and keep our soils productive. 它们纯洁我们的水源，使我们的土壤具有生产力。

Bacteria synthesize vitamins in our gut, convert the things we eat into useful sugars and polysaccharides, 它们合成我们肠胃中的维生素，将我们吃进去的东西变成有用的糖和多糖，

and go to war on alien microbes that slip down our gullet. 向溜进我们肠胃系统的外来细菌开战。

We depend totally on bacteria to pluck nitrogen from the air and convert it into useful nucleotides and amino acids for us. 我们完全依靠细菌来采集空气里的氮，将氮转化为对我们有用的核苷酸和氨基酸。

It is a prodigious and gratifying feat. 这是个令人惊叹而又让人满意的业绩。

As Margulis and Sagan note, to do the same thing industrially (as when making fertilizers) 正如马古利斯和萨根指出的，在工业上要干同样的事（比如在生产肥料的时候），

manufacturers must heat the source materials to 500 degrees centigrade and squeeze them to three hundred times normal pressures. 工厂必须把原材料加热到500摄氏度，挤压到300倍于普通的大气压。