Thursday, 7 June 2012

The Egg & Sperm Race, by Matthew Cobb

I like science. It wasn’t a subject I excelled at in school; to my disappointment I only just scraped through my final year. Nevertheless I find mankind’s attempts to come to grips with the world around it deeply fascinating. From the far reaches of deep space to tiny subatomic particles, from the bottoms of oceans to the human brain, the scope of science is vast and encompasses every aspect of our lives. One of the big questions we have grappled with over the centuries is the origin of life. The Egg and Sperm Race takes us back to pre-enlightenment days; before Darwin could develop his theory of evolution we had to discover the answer to a much more fundamental problem: how do we breed?

It seems so obvious to us now - even a child can explain the basic concepts behind fertilisation - however not so many centuries ago even the top thinkers of the time were deeply muddled as to how life came about. As Matthew Cobb makes clear, even basic facts we take for granted aren’t that easy to establish. For example, there is no obvious indication of pregnancy for some time after intercourse; while people knew there was a connection, they didn’t know what that connection was. Some of the ideas circulating, even amongst learned members of society, seem ridiculous to us now. Since insects were so clearly identified with dirt and decay it was widely believed that they spontaneously generated in rotting matter. No wonder mammalian reproduction was little understood! While it was generally accepted that offspring took after their parents it wasn’t seen as the hard and fast rule we know it to be. In the seventeenth century the newly formed Royal Society was happy to listen to stories of mutant children of cats bred with rabbits. Although they were a bit confused, the Royal Society, and other European scientific institutions like it, began to develop a more rigorous approach to science.

It is easy to think of the history of science as a series of eureka moments, such as Newton’s apple, but Cobb gives a good sense of how science really happens: hard work and the slow accretion of facts over time building a picture. He also shows how poor methodology, and sometimes luck, play influential roles. William Harvey, one of the first ovists (those who believed the egg was primarily responsible for reproduction, as opposed to spermists), unfortunately chose deer to study. There was no way Harvey could have known, but deer are unusual in many ways, including that mating often begins before females are fertile. This lead Harvey to some false conclusions which, if he had made a luckier choice of animal, he might have avoided.

Another prominent figure in this book, Antoni Leeuwenhoek, was a Dutch draper who arose to prominence in the field of reproduction through his skill with a microscope. He was unusual in that he wasn’t from an aristocratic background; nevertheless he became a regular correspondent of the Royal Society. In 1677 Leeuwenhoek discovered spermatozoa, which was a remarkable achievement. The story Cobb relates though has a charm of its own. In his letter to the Royal Society Leeuwenhoek was at pains to clarify that he did not come across his semen sample through any immoral means, rather it was ‘the excess which Nature provided me in my conjugal relations‘. Leeuwenhoek’s wife must have been a very understanding woman!

Throughout this book Cobb does an excellent job of explaining the science clearly, in layman’s terms. He is particularly good at illustrating how cutting edge some of the techniques were for the time. This is helpful - as I have said it is difficult for us to imagine a time when reproduction was so poorly understand. He also brings to life society of the time, and the scientists working within it. This is a great pop-science read, accessible without being oversimplified.

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