Biological applications of large electric fields: some history and fundamentals

The history of electric fields in biology is summarized briefly. Physical concepts important for explaining the action of electric field pulses on biological objects are reviewed: relation of pulse width to frequency spectrum; precise meaning of "conductor" and "dielectric"; electrical properties of living tissues; translatory and rotational motion of electric charges and dipoles; effects of inhomogeneity, diffusion and viscosity; conditions for validity of linear models; electrical mobility of ions in membrane channels and membranes; conditions for radiation; reflection, refraction, and penetration of radiated fields; effect of radiated magnetic fields on chemical reaction rates; radiation pressure; electrostriction; the problem of distinguishing between thermal and nonthermal effects. The rationale for close collaboration among biologists, engineers, physicists, and physicians is discussed.