Metropolis

You are a metropolis.

On your eyelashes, creatures crawl, tiny eyeless mites with stubby legs and translucent bodies; creatures which are born, live and die in the follicles of those hairs on your eyelids. 

Yes. I am talking about this.

They eat a little of the oil your sebaceous glands produce, and they have such efficient digestive systems that they don’t defecate at all (in case you’re wondering whether mite faeces is oozing down your lashes as you read this, no, it isn’t).

Your mouth is a teeming wilderness, populated by millions of flora and fauna, including a substantial portion of the hundred trillion bacteria which inhabit your body. Bacterial colonies stick to the top of your tongue in mats and sheets, and swim through the mucoprotein layer covering your teeth and membranes. Protozoa of the Entamoeba group crawl around your gingival crevices and you swap them around with your significant other with every deep kiss.

Feel like snogging now?

A few of these creatures are harmful, stowaways with an agenda as it were; a much larger majority are, under normal circumstances, passengers in your mouth, eating dead cells, food particles and generally doing you no harm and possibly – by occupying space that would otherwise be taken up by the harmful ones – doing you some incidental good.

Then, let’s take a look inside your intestines. Even if you aren’t among those who harbour cute little parasitic worms (or, for tapeworm hosts, cute big parasitic worms), your intestines are full of tiny creatures hopping, skipping and jumping around, from bacteria to yeasts. It’s more than a rain forest in there in terms of the richness of life, more than a coral reef. And you cannot survive without those microorganisms. You are dependent on them to keep you alive. For one thing, some of them break down cellulose in the plant matter you eat, thus liberating the interior of the cells to your digestive juices. For another, they, even those whose only purpose of existence is to nibble fastidiously at fragments of your forming faeces, aggressively block out the others – the millions upon millions of less than pleasant microorganisms you swallow each day. 

I have a gut feeling about this.

Want to know what would happen if those microorganisms all vanished from your gut? Have you ever had a course of antibiotics and suffered the side-effect of diarrhoea? Yes? Well, that’s because the antibiotics have waged indiscriminate chemical warfare on the forests and jungles inside you, like a kind of Agent Orange in your inner Vietnam. And until the survivors grow back to fill the empty spaces, undigested food flows through you like...well, like undigested food flowing through you. Now imagine that going on all the time, and worse; imagine all these microbes vanishing. Will the space they vacate, all that lovely real estate, remain empty? Of course not; it will be flooded by invaders, murderous marauders from the outer light, whose only purpose is to consume and destroy.

Consume and destroy you, that is.

But such a marvel is evolution that it fills every nook and cranny, quite literally, with life, and seeks out, always, to fill it with viable life. That is why the passengers on your body block the enemy without; they want to keep living, and it's in their interests that you keep living. They've evolved to help keep you alive, just as you've evolved to tolerate their presence in your body.

You are a metropolis, larger by far than any the mere human race has ever built, and your countless citizens are keeping you a living city, simply by going about their daily business. You are a city that never sleeps, that never can. So look in a mirror, and call yourself we.

And tonight, as you lie down to put your conscious brain to rest, remember those mites crawling demurely along your eyelashes, eating, meeting, breeding, and otherwise leading their own doubtless meaning-filled lives. Remember the teeming millions of your passengers, who aren’t even aware that you exist as a living entity, and yet for whom you are a universe. Think of them a little.

Pleasant dreams.