THE OUTER REACHES OF LIFE

Diversities of life among the microbes make up 18 generally lively essays by Postgate that—for the general reader—waver on the edge of opacity. Twenty-five years ago, Postgate wrote a well- received textbook, Microbes and Man, now in its third edition. Postgate edges towards chummy tales of the microbes, though his learnedness, however lightly worn, also rises up and may well cool the ardor of the more uninformed reader. He is not Lewis Thomas, or, simply, he is less entertaining than Thomas. He tells us why some microbes can flourish at high temperatures, ``some thriving at, and even above, the normal boiling point of water,'' while others cook like an egg. Readers will learn of the varieties of alcohol—ethanol (wines and spirits), methanol, pentanol, glycol (automobile anti-freeze), glycerol (glycerine), and so on; why ice formation is lethal to cells and how glycerol prevents it and allows for cold-storage of cells and organs needed for transplants. We also find how microbial life survives at the highest and lowest atmospheric pressures, including the deep-sea bottom, and how life of the terrestrial king might evolve into highly complex forms even on a massive planet like Jupiter with its strong gravity and high surface pressures. We learn about the biological effects of salt and what happens when salts dissolve in water. Although microbes die under certain kinds of stress, the products of bacterial cell division show a seeming immortality among microbes (and yeasts); microbes are sexless and reproduce by fission, so that a microbe that divides remains itself, is neither mother nor daughter. Lifts your head out of the muddle.