This book contains the papers presented at the International Conference<br >on Comparative Physiology held at Crans-sur-Sierre in September 1976.<br > One of the strengths of the comparative approach to physiology is that<br >one can find out from a range of organisms what is fundamental about<br >solving any particular physiological problem. This is often shown most<br >clearly when the organisms selected are those that are faced with the most<br >extreme physiological stresses. For example， because of their small size<br >terrestrial arthropods face daunting problems of water economy; some of<br >them achieve the impressive feat of absorbing water vapour from the air.<br >Chapters in the first part of this book describe the fascinating ways in<br >which this is achieved by different organisms. We were fortunate enough<br >to have papers from all the leading workers in this new and intriguing field.<br >Other articles in the first section describe recent advances in the thorny<br >problem of how water movements across epithelia are generated by<br >solute movements.<br > The theme of the second section of the book is animals under the stress<br >of living in ionically extreme or unbalanced environments. Included are<br >accounts of how bacteria， crustaceans， insects， fishes and birds cope with<br >unusual difficulties in ionic regulation.<br > In the final section we have， as in our previous conferences， brought<br >together biologists and physicists to illuminate a particular topic. This time<br >the spotlight was turned on the role of fluid mechanics in biology. The<br >biologists described various sorts of fluid flows occurring both inside and<br >around the outside of organisms and covered such topics as ciliary and<br >flagellar beating， hydrostatic skeletons and insect flight. These papers were<br >most satisfyingly complemented by more theoretical ones on the underlying<br >hydrodynamics and aerodynamics involved.<br >