IT』S PROBABLY NOT a good idea to take too personal an i in your microbes. LouisPasteur, the great French chemist and bacteriologist, became so preoccupied with them that hetook to peering critically at every dish placed before him with a magnifying glass, a habit thatpresumably did not win him ma invitations to dinner.
In fact, there is no point in trying to hide from your bacteria, for they are on and around youalways, in numbers you 』t ceive. If you are in good health and averagely diligent abouthygiene, you will have a herd of about orillion bacteria grazing on your fleshy plains—about a huhousand of them on every square timeter of skin. They are there to dineoff the ten billion or so flakes of skin you shed every day, plus all the tasty oils and fortifyingminerals that seep out from every pore and fissure. You are for them the ultimate food court,with the venience of warmth and stant mobility thrown in. By way of thanks, they giveyou B.O.
And those are just the bacteria that inhabit your skin. There are trillions more tucked awayin yut and nasal passages, ging to your hair and eyelashes, swimming over thesurface of your eyes, drilling through the enamel of your teeth. Yestive system alone ishost to more than a hurillion microbes, of at least four huypes. Some deal withsugars, some with starches, some attack other bacteria. A surprising number, like theubiquitous iinal spirochetes, have able fun at all. They just seem to like tobe with you. Every human body sists of about 10 quadrillion cells, but about 100quadrillion bacterial cells. They are, in short, a big part of us. From the bacteria』s point ofview, of course, we are a rather small part of them.
Because we humans are big and clever enough to produd utilize antibiotiddisiants, it is easy to vince ourselves that we have banished bacteria to the fringes ofexistence. Don』t you believe it. Bacteria may not build cities or have iing social lives,but they will be here when the Sun explodes. This is their pla, and we are on it onlybecause they allow us to be.
Bacteria, never fet, got along for billions of years without us. We couldn』t survive a daywithout them. They process our wastes and make them usable again; without their diligentmung nothing would rot. They purify our water and keep our soils productive. Bacteriasynthesize vitamins in ut, vert the things we eat into useful sugars andpolysaccharides, and go to war on alien microbes that slip down ullet.
We depend totally on bacteria to pluitrogen from the air and vert it into usefulides and amino acids for us. It is a prodigious and gratifyi. As Margulis andSagan o do the same thing industrially (as when makiilizers) manufacturers mustheat the source materials to 500 degrees tigrade and squeeze them to three huimesnormal pressures. Bacteria do it all the time without fuss, and thank goodness, for neranism could survive without the nitrogen they pass on. Above all, microbes tioprovide us with the air we breathe and to keep the atmosphere stable. Microbes, including themodern versions of obacteria, supply the greater part of the pla』s breathable oxygen.
Algae and other tiny anisms bubbling away in the sea blow out about 150 billion kilos ofthe stuff every year.
And they are amazingly prolific. The more frantic among them yield a new geionihan ten minutes; Clostridium perfringens, the disagreeable little anism that causesgangrene, reprodu nine minutes. At such a rate, a single bacterium