Preface vii 



To develop a branch of natural science as a logical structure, it is 

 desirable to describe the behavior of highly organized systems in 

 terms of the properties of simpler systems. This is not always feasible 

 and in some cases cannot be followed at all. For example, in 

 physics one discusses electric currents before attempting to present 

 electronic conduction bands in metals. In this text we have tried 

 to start from more general topics with which all varieties of 

 readers will be intuitively familiar, and proceed to simpler but more 

 abstract ideas. Thus, Part A on special sensory systems includes a 

 chapter on vision and the eye; the neural aspects of vision are pre- 

 sented in a chapter following discussion of nerve activity ; the molec- 

 ular actions which convert light into nerve impulses form the basis 

 of a chapter in Part D which deals with molecular biology; finally, 

 the eye as a coding mechanism is discussed in a chapter on informa- 

 tion theory located in Part E. Specialized physical instruments, 

 necessary for these and other studies, are discussed in the last part 

 of the text. 



All of the areas of the text taken together comprise biophysics. 

 Within each area a careful selection has been made from a variety 

 of topics all of which are part of biophysics. The topics included 

 in this text were chosen not only for their relative importance, but 

 also for their suitability for presentation in a one-year course for 

 students with a variety of backgrounds. Other possible topics are 

 included in the discussion questions at the end of each section of 

 the text. 



It is the author's hope that the reader of this book will gain an 

 insight into the nature of the topics included in biophysics, recog- 

 nizing the attempt to quantify and develop biological problems in 

 terms of physical models wherever this is practical. The reader 

 should become acquainted both with the biological basis of the 

 various areas of biophysics and also with the essential role of math- 

 ematical analysis in most biophysical problems. 



The author wishes to thank his many students and friends, all of 

 whom have had such a profound influence on the material in this 

 text. It is not possible to name all who have helped, but special 

 mention is made of those who contributed an extra amount of their 

 time and ideas. They are: Dr. A. Anthony and Dr. G. K. Strother 

 of the Pennsylvania State University; Dr. A. A. Benson of the Univer- 

 sity of California; Dr. K. N. Ogle, Dr. A. L. Orvis, and Dr. C. M. 

 Gambill of the Mayo Clinic; and Dr. A. S. Brill of Yale University. 

 The permission of numerous publishers and authors to reprint their 

 figures is also gratefully acknowledged. Without secretarial help, 

 this text would never have been completed; special thanks are due 



