Electricity and Magnetism in Biological Systems , D. T. Edmonds Oxford U. Press, New York, 2001. $75.00, $40.00 paper (286 pp.). ISBN 0-19-850680-5, ISBN 0-19-850679-1 paper
In the introduction to Electricity and Magnetism in Biological Systems , Donald T. Edmonds comments that “all biological function must eventually be understood in terms of electromagnetic forces.” He writes later, “It is the aim of the first ten chapters of this book to describe electromagnetic theory in a manner that makes it more accessible to students of medicine, biology, biochemistry, and chemistry than the formal mathematical approach of physics books.” That first group of ten chapters makes up part I, The Basic Theory, which represents about 60% of the book. Six to ten problems are appended to the end of each chapter, usually with one worked out in detail.
While the exposition was clear, I judged that this part of the book was “more accessible” only to the extent that it was less ambitious than the electrodynamics texts I have used in teaching advanced undergraduate physics majors. For the most part, the material was treated conventionally, except that no use was made of vector algebra and vector operators. However, the discussion of conductivity, which emphasized ion currents, random-walk processes, and Fick’s first law, was an unconventional exception, especially useful for biologists.
In his part II, Applications, about 25% of the book, Edmonds addresses six biological topics in which the introductory physics supposedly plays an important role; chapters 11 through 16 cover, respectively, ions in aqueous solution, the Debye Layer, ions in narrow pores, a magnetic animal compass, ion/ion coport or counterport, and theory of pulsed nuclear magnetic resonance. No problems are appended to these chapters, but references are listed. The book ends with three appendices, on mathematics, on the Boltzmann distribution, and on thermodynamics and the chemical potential. Each is followed by a few pages of hints for solutions and numerical answers to the problems.
Here, I find a disconnect between parts I and II. While part I is a textbook for beginning students, part II seems more a set of somewhat didactic special-topic essays requiring much more sophistication on the part of the student than does the conventional physics of part I. Moreover, the selection of subjects seems to reflect more the author’s special interests than matters central to biophysics. While Edmonds devotes a chapter to coport and counterport ion transfer across cell membranes, emphasizing his own important contributions, he mentions voltage-gated ion channels in only one offhand sentence. Surely this aspect of membrane ion transfer is directly electrical and is central to much biology! Conversely, while animal navigation is great fun, and a special interest of mine as well as of Edmonds’s, matters like the cable-like signal transmission properties of axons, dendrites, and the like, which are not mentioned, are certainly much more important. Indeed, that discussion of animal navigation is far enough in advance of what we know with certainty that I found it possible to disagree with elements of his essay. And while the discussion of the flowthrough ion channels, which touches on Edmonds’s recent researches, is elegant, I was disturbed that the Goldman-Hodgkin-Katz description was not even mentioned. Even if Edmonds believes that this half-century-old description is simplistic, it is still central to most discussions of channel flow, and any student should know something of it.
In summary, this text seems like two separate books not happily wed. Part I is a rather conventional electrodynamics text that might be considered for US biology students after their standard elementary physics course. While the exposition of the chosen topics, including Maxwell’s equations in their integral form, was clearly presented, I am one of those who would prefer to introduce such students to vectors (described only in a mathematical appendix) and to the notation of vector operators (not mentioned anywhere). I argue that students sophisticated enough to appreciate the biological topics in part II should be comfortable at least with the qualitative meanings of the operators div, grad, and curl that they will meet in research papers.
Part II is a brief, 75-page set of six idiosyncratically chosen essays on a few topics of special interest to Edmonds. (Ten of the forty-six references listed in Part II were to Edmonds’s papers.) I enjoyed these essays and learned something myself, but I see no place for this section in the education of undergraduate students in American colleges and universities.
