Nonfiction Book Review: I Contain Multitudes

Ed Yong, I Contain Multitudes: The Microbes Within Us and a Grander View of Life (2016)

When I was asked to contribute a “book I should have read” to Keeping Up with the Penguins, this one sprang to mind. And spurred by that reminder, I did finally read it!

I can now recommend it to everyone for a good dose of actual scientific information, given the current state of anti-microbial hysteria. As you may already be aware, wiping out all microbial life in an area gives a free playing field for aggressive, resistant microbes to grow and become even more resistant, unchecked by the more benign ones that would normally surround them. It’s really, really not a great idea.

We need to find other ways to live with our invisible friends (and foes), other than spraying everything with disinfectant. When faced with a scary and overwhelming threat, that reaction is natural — and sometimes may be warranted — but as an overall policy, it’s already backfiring. (Did you know that 90,000 people in the US die each year from infections they pick up in the hospital?)

We need to learn more about how the microbial world really works, and about the interconnectedness of all life, before wildly destroying what we don’t even understand. The threats are real, but so is the potential to counter them in more life-enhancing ways.

Just a few of the things I learned from this book include:

  • Microbes are everywhere, in vast numbers, and they play extremely important roles in the living world. No microbes, no life as we know it.
  • Their discovery via the earliest microscopes started with wonder and open-mindedness, but then changed to a warlike narrative of “kill the bad bugs” that still haunts us today.
  • There aren’t actually good bugs and bad bugs. The same microbe can play different roles even within the same organism. The key is for larger organisms to develop ways to manage and live with a variety of microscopic life.
  • Symbiosis — living together — is a principle that is rooted within our very cells, the structure of which came about long ago through one microbe absorbing another that then gave it an energy boost and an evolutionary advantage.
  • There are incredibly weird and fascinating examples of symbiosis in the natural world, enabling organisms to resist toxins, fight off unwanted invaders with antibiotics, and even glow in the dark. Biologists are just beginning to understand these relationships.
  • The “microbiome” makes an important contribution to evolution, which is based not only on an organism’s own genome but on the microbes it inherits or acquires — something that can cause sudden and dramatic changes in evolutionary processes that are usually much slower and more gradual.
  • Microbes may play a role in treating mood disorders, obesity, antibiotic-resistant infections, and other ailments. The possibilities are very exciting, but a lot more research is needed, so don’t start doing your own fecal transplants.
  • Breastfeeding plays a unique and surprising role in forming an infant’s microbiome for life.
  • Sterile, microbe-free mice (used for lab experiments) are bizarre and unhappy creatures.

Ed Yong is a fine guide to this complex topic, with a clear and engaging style that can speak to non-scientists without undue oversimplification — something that is unfortunately often done in the popular press. Aggressive calls for extermination and overhyped touting of probiotic health cures  are both too extreme and short-sighted. To counter this, we need to learn more, to have our eyes opened to the hidden world that lies all around and within us. Our life on earth truly depends upon it.


11 thoughts on “Nonfiction Book Review: I Contain Multitudes

  1. I have been thinking of reading this. I almost picked it up recently. The points that you list are all fascinating. There is so much to the universe that we do not see or usually think about that is profoundly important.


    1. Yes, and microbes are particularly profoundly important. If you do pick up this book, I hope you’ll find it as enlightening as I did.


  2. This has been on my list for ages, and I really need to read it! Ed Yong has been writing these lengthy articles in The Atlantic explaining various things about coronavirus since all this began, and it’s been tremendously helpful and great. He’s such a clear, careful writer!


  3. How very interesting! When we lived in the UK there seemed to be endless adverts for products that apparently ‘kill 99.9 per cent of all germs’ which I assumed meant microbes and I was always puzzled by that. I mean, OK, maybe that’s fine when you’re talking about the chopping board you use for preparing food. But surely it’s excessive when you’re talking about inside your loo? Or am I just a hideously dirty and unhygienic person? Perhaps this book will tell me…


    1. One of the points he makes is that frequently cleaned toilets have more dangerous bacteria than those that are not so obessively sterilized – because all of their bacteria come from fecal matter, vs. the friendlier bacteria that live in the environment. It goes against our normal thinking, but that’s what this book is for – to help us overcome those prejudices.


      1. And that is so important! If there is one thing I’ve learnt from the Covid-19 crisis, it’s that what appears to be ‘common sense’ is not always trustworthy.


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