Bryson writes (p.324); "A successful virus is one that doesn't kill too well and can circulate widely. That's what makes flu such a perennial threat." But of course Bryson knew that it's not only flu we have to worry about. On the next page he says:
It's remarkable that bad things don't happen more often. According to one estimate…the number of viruses in birds and mammals that have the potential to leap the species barrier and infect us may be as high as 800,000.Some of the reported reactions, or absence of reactions, by many people to the Covid19 epidemic shows there is widespread ignorance of how the body works in health and disease. Bryson's book should help to remedy this deficiency; it certainly scores highly for readability. He writes in a relaxed style with plenty of jokes and often funny anecdotes, much as he did in his science book A Short History of Nearly Everything. If you liked that book you will probably like this one as well.
The new book is remarkably up to date. I spotted only one point where recent research has overtaken a statement (that men and women have different heart attack symptoms). And it's fairly comprehensive, covering all the main areas of structure and function that most people have heard of (and some that they probably haven't, such as the thymus). This takes up nineteen chapters; the remaining four are on selected diseases, including cancer, and conclude, rather sombrely, with the end of life. (Microbes and the immune system have already been discussed in the earlier chapters.) Numbered references are provided for all statements throughout.
There are a number of features that I liked particularly. One is that Bryson frequently points to our inability to answer many quite basic questions, such as why we age, what is the cause and function (if any) of the menopause, and why we (and practically all other animals) sleep. We are of course also ignorant of the causes of many diseases.
I also enjoyed Bryson's debunking of popular myths, including the claims that we only use ten per cent of our brains, that we lose more heat through our heads than through the rest of our bodies, and that we all ought to drink eight glasses of water a day. But my favourite example has to be the hyping of free radicals as the cause of ageing and the associated claim that antioxidants are the elixir of youth.
This makes no sense biologically and has been conclusively demonstrated not to work in practice, yet sales of antioxidants provide a hugely lucrative source of revenue for people who sell them. (For more details see one of the books cited by Bryson in his bibliography, Nick Lane's Power, Sex, Suicide: Mitochondria and the Meaning of Life.) Thanks to Lane I already knew this but but I hadn't come across the funniest part of the story, which is that whole idea originated in the mind of a research chemist, Denham Harman, who in 1945 chanced to read an article on ageing in his wife's copy of Ladies' Home Journal.
Bryson brings in evolution a number of times in different contexts, which is good (he even has a sly dig at the Intelligent Designers), but I was less happy to find him talking in a number of places about things being 'good for the species'. While group selection theories are not totally discredited by evolutionary biologists they are little used today and these references would probably have been better omitted.
Inevitably in a book of this kind there will be topics omitted that some readers might have liked to see included. I was surprised to find no mention of BCG vaccination in the discussion of tuberculosis. But I was glad to find a short consideration of whether fever should be suppressed or not (p.187). Is it an unwanted epiphenomenon or part of the defence mechanism against infection? Once more we are confronted by an unresolved medical question, but the answer we give may be literally vital to many people in the coming months.
Screening for disease, especially cancer, has been in the news a lot recently. There is disagreement among experts about the effectiveness and desirability of breast and prostate cancer screening. Bryson presents the main questions that arise but his own position remains cautiously noncommittal, which is clearly appropriate for a book intended for a wide general readership.
All this isn't to say that men should avoid PSA tests or women breast cancer screening. For all their flaws, they are the best tools available and they do indubitably save lives, but those undergoing screening should perhaps be made aware of the shortcomings. As with any serious medical issue, if you have concerns you should consult a trusted physician.This book succeeds pretty well in providing information that will be interesting and useful to many readers, and it couldn't have appeared at a more appropriate moment.