PD Smith

A plague on all our houses

08 December 2007 | Hitchens, Reviewing, scientists | Post a comment

I've been reading a fascinating study of microbes - Deadly Companions by Dorothy H. Crawford, just published by OUP. Her book shows how bacteria, viruses and other microscopic organisms have proven themselves to be masters of evolution, deftly exploiting any opportunity created by our changing lifestyles.

Deadly Companions

Our bodies are teeming with microbes - 1014 to be exact; that's about a kilogram in weight. Astonishingly, they outnumber our own body cells by 10 to 1. According to Crawford: "We relative newcomers to the planet emerge from the safe environment of our mother's womb pristine, untouched by the infectious microbes, but within hours our bodies are colonised by swarms of them, all intent on living off this new food source."

But, happily, they're not all bad: at least 400 of them help our bodies ward off other, deadly microbes. Of the million or so microbes known to science, only 1,415 cause human diseases. Of course, they don't mean to harm us; our diseases are just side-effects of their life-cycles. But ever since Homo sapiens evolved, we have been locked in mortal combat with microbes, our deadly companions. In fact, Crawford argues they have shaped our history as a species.

You can read my review of Crawford's excellent book in today's Guardian Review. In the same issue I've also reviewed The Portable Atheist: Essential Readings for the Nonbeliever, a wonderful anthology selected by Christopher Hitchens, and Bad Medicine: Doctors Doing Harm since Hippocrates, by David Wootton, a controversial view of the history of medicine. Both ideal Christmas stocking-fillers! You can read my reviews of these here.

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