Life at the extreme by Frances Ashcroft, reviewed by Pat Boran

Life at the Extremes. Frances Ashcroft.

PAT BORAN

(Sunday Business Post)

Between the devil and the deep sea is one well-known phrase, of nautical origin, which seems to describe the experience of being exposed between perilous alternatives. While the original actually referred to the varying level of the waterline on board ship (the devil being the gunwale and therefore the water's uppermost limit), its proverbial cousin conjured danger and demons and, importantly, kept the notion of a correct path between extremes in the mind's eye.

Nevertheless, just as successive generations of explorers and adventurers have attempted to go beyond the Ultima Thule, the furthest known place, as Virgil had it, the known but inaccessible all around us has been an equal source of provocation. While many have desired to climb to the top of the world's highest mountains or soar into and beyond the earth's atmosphere, other adventurers have walked down the road and, bearing a raw steak and an egg, have spent fifteen minutes in an oven at 115 degrees Celsius to emerge relatively unscathed, egg and steak well done.

In her first book for the general reader, Frances Ashcroft, a Professor of Physiology at Oxford, and something of an adventurer herself, looks into the physiology of what happens to people in these various extremes of heat and cold, pressure and weightlessness. Early on she gently corrects Dante for placing the circle of ice below the circle of fire in his Inferno, but then, towards the end of the book, introduces an organism which, confounding previous ideas of what constitutes life, exists some 2.7 km below the surface of the earth, without light or oxygen. And its name? Fittingly, Bacilus infernus.

Despite such occasional references to literature, and to the Bible in particular, Ashcroft's real subject is what actually happens to the organs under the various pressures of bungee jumping, deep-sea diving and dizzying ascent, rather than the matter of how these have been described. In the course of the book we learn that balloonists pass out at about 9,000 feet, while divers who regularly go down below 200 metres face the invisible but very real danger of bone collapse. We learn that many of our favourite stories of convicts on the run hiding in lakes and breathing through reeds are impossible at a depth of more than a metre (due to pressure on the lungs). We also learn why we so often need to pee as soon as we enter even a warm sea on holidays. (The reduced pressure of the water causes a blood rush from the feet and legs up to the heart, which in turn alters the level of two hormones which 'influence water uptake by the kidney'. So now you know.)

Would that all the fascinating information here were as amusing and lightly approached. In her chapter Life in the Cold, Ashcroft details the extraordinary and horrific scenes of the retreat from Moscow in 1812 during which the freezing conditions provided such a good anaesthetic that starving soldiers were able to butcher their mounts for food and yet keep the horses alive. 'We saw some of these poor horses walking for several days with large piece of flesh cut away from both thighs,' she quotes one senior sergeant of the 2nd Cuirassiers, though her own phrase for the scene, 'the living larder' views the horror equally head on.

What makes this book such a pleasure to read and so stimulating is the breath and depth (so to speak) of material and experience covered here, Ashcroft's subject matter having fascinated the ancients as much as the post-moderns. That altitude sickness, for example, was first described by the Chinese in 32 BC is hardly a surprise, though that it came in a book which tells of a journey through a range which includes Great Headache, Little Headache and Fever mountains is a wonderful detail. The fact that the Incas used their own familiarity with the problem as a way of escaping invaders reminds the rest of us, in our cosy comfortable homes that, at least on occasion, a journey into the extremes might well be what we need to stay alive.