SYSTEMS PHYSIOLOGY

SYSTEMS PHYSIOLOGY By S. A. Talbot and U. Gessner. (Pp. 511; illustrated; £12-50.) Wiley: New York. 1973. The construction of models as a method of tackling physiological problems has a long and honourable history. Although a model is discredited when it proves inadequate to 'explain' biological phenomena, the use of argument by analogy obviously fulfils something fundamental in human thought. The model need not be a material one, indeed it is more flexible if it can be handled with mathematical symbolism rather than with string and sealing wax. Surely this was the real meaning of Kelvin's famous aphorism about measurement. The mathematical and technological capabilities of each generation affect the models which are fashionable. The postwar years have seen the development of techniques for the control of electronic machines including extremely complex computers and many engineers are now trained to think 'cybernetically' and to use systems analyses. The applicability of 'feed-back control' to many physiological homeostatic mechanisms is so obvious that many scientists without biological training have become 'bioengineers'. This book is an attempt to provide a source book for them and for the many biomedical researchers who have taken the trouble to learn the necessary mathematics but it rightly insists that systems physiology transcends control systems physiology, with emphasis on adaptive and purposive activity. At an early stage the authors face the question whether the models are elaborate exercises in curve fitting or genuinely throw light on intrinsic mechanisms. There is a laudable attempt to assess the usefulness and strength of the tools and concepts provided. For the bioengineers this book is a most useful introduction. Many medical research workers would find the applicable chapters valuable and stimulating. About 60%o of the book is on neurophysiological subjects and the remainder on vascular, respiratory, hormonal, and temperature control systems. The late Dr Talbot was associate professor of medicine (biomedical engineering) at the Johns Hopkins University, Baltimore, and Mr Gessner, now in Switzerland, was an associate professor in the same school. This is a valuable book but it requires a real effort by the reader. The mathematics was beyond this reviewer.