Soil

There is a delightful moment at the end of this book when Frank Ashwood is out looking for soil-dwelling invertebrates in his adopted New Zealand home. Suddenly he proclaims: ‘I notice something and my heart skips a beat. A velvet worm.’ He goes on to tell us that the discovery of two of these rare organisms in one day is ‘a thing of dreams’. Far from scoffing at his excitement, the reader has long come to share his enthusiasm for the extraordinariness of velvet worms. They are, after all, lozenges of blue and orange stripes rolled in tiny sequins. That we have also come to see the full beauty, abundance and sheer weirdness of the whole subsoil realm is a measure of Ashwood’s wider achievement.

Over the long span of human existence, different cultures have held varying notions as to how responsible we are for our own thoughts and beliefs. Before the dawn of the Abrahamic religions, and in places untouched by these faiths, it tended to be the rule that individual members of the group could only be understood as parts of the whole, or in the grander cosmic scheme of things. The ascendence of Christianity in Europe, with its idea of the indivisible soul, tilted matters more towards a belief in individual agency and accountability. This concept, secularised by Descartes, who gave us the commanding rational ego, has proved resilient ever since, despite the best efforts of Freud, neuroscience and gene selection theory to dethrone it.

As humans, we are supposed to have an aversion to slime. It should repel us. Objects and organisms that might be harmful trigger feelings of disgust which keep us away. And, according to the biologist Susanne Wedlich, the common denominator of ‘wide-ranging microbial threats, covering sickness, sex, death and putrefaction’ is their sliminess. It is easy to test this theory. Google ‘slime moulds’ and note your first response. They are gross. But these organisms are worth sticking with. Japanese researchers once conducted an experiment using a slime mould and a map of the country. They put the mould on top of Tokyo and dropped food on to the city’s surrounding towns.