I Contain Multitudes: The Microbes Within Us and a Grander View of Life

by Ed Yong

the-envelope calculation that became unfortunately enshrined as fact.7 The latest estimates suggest that we have around 30 trillion human cells and 39 trillion microbial ones – a roughly even split.

There are fewer than 100 species of bacteria that cause infectious diseases in humans;

“Every species has come into existence coincident both in space and time with a pre-existing closely allied species,”

Speaking of palms, your right hand shares just a sixth of its microbial species with your left hand.

The zookeeper shows us a colony of naked mole rats skittering around a set of interconnected plastic tubes. They are distinctly unattractive animals, like wrinkled sausages with teeth.

This type of partnership gained a new term – symbiosis, from the Greek for ‘together’ and ‘living’.13 The word itself was a neutral one, implying any form of coexistence. If one partner benefited at the expense of the other, it was a parasite (or a pathogen if it caused disease). If it benefited without affecting its host, it was a commensal. If it benefited its host, it was a mutualist. All these styles of coexistence fell under the rubric of symbiosis.

handyman-cum-servant.

Potential career path?

in South America, acacia trees rely on ants to defend them from weeds, pests, and grazers. In return, they give their bodyguards sugary snacks to eat and hollow thorns to live in. It looks like an equitable relationship, until you realise that the tree laces its food with an enzyme that stops the ants from digesting other sources of sugar. The ants are indentured servants.

manage our relationships with our resident microbes. It’s more about balance and good management than defence and destruction.

he harvested microbes from fat and lean mice, and then fed them to germ-free rodents. Those that got microbes from lean donors put on 27 per cent more fat, while those with obese donors packed on 47 per cent more fat. It was a stunning result: Turnbaugh had effectively transferred obesity from one animal to another, simply by moving their microbes across.

“America is a constipated nation,” he said, indelicately. “If you pass small stools, you have big hospitals.”

I find it ironic that theory, which is the epitome of cooperation and togetherness, can deeply divide people who spend their entire time thinking about cooperation and togetherness.

These same glowing microbes got into the wounds of soldiers during the American Civil War and disinfected them; the troops called the mysterious protective light the “Angel’s Glow”.