PREFACE 



As a result of the increased demands for physics by students whose 

 primary interests lie in the biological sciences, this book has been written 

 with the hope that it may lead to a fuller appreciation and understanding 

 of the applications of physics to biological problems. 



I trust that it will prove suitable as a textbook for mature students 

 who have had a year's work in college mathematics followed by one 

 year's study of the fundamental principles of physics and chemistry. 



In lieu of a more appropriate name, it is proposed to designate all 

 those biological observations which are explainable in terms of physical 

 principles as biophysical phenomena. Which topics are representative 

 of an ideal cross section of the available biophysical material is at present 

 a debatable question. In order to avoid the imputation of superficiality 

 in dealing with this cross section, only such subjects are discussed as are 

 representative of the major subdivisions of physics. 



In the general field of radiation no better example can be found of the 

 cooperative effect of the biological and physical sciences than the problem 

 of radiation therapy. Here, as in much of the biophysical research, the 

 tools have been supplied by the physicist so that the medical scientist 

 can use them to point the way in which the physicist should work to 

 make the tools progressively more effective. This cooperative progress 

 in the field of radiation is portrayed in the chapters on the biophysically 

 active x-rays and applied radioactivity. 



The influence of physics on physiological optics and acoustics is pre- 

 sented in the chapters discussing the biophysical characteristics of the 

 eye and auditory biophysics. 



In the field of physical optics, where its applications merge with the 

 medical sciences, the emission and adsorption of biophysically active 

 light are discussed because of the general desire for information dealing 

 with the effect of ultraviolet radiation on life processes. 



The possibility of revealing the nature of the living cell membrane is 

 at present being pushed with great success through the study of the 

 physical properties of molecular-film structures. The chapter discussing 

 structure and properties of surfaces and membranes is introduced to 

 illustrate how the modern molecular concept of matter is influencing the 

 developments in this biophysical field of investigation. 



