iv PREFACE 



The chief writing problem has been to achieve simplification without 

 oversimplification so that statements have a reasonable range of validity 

 rather than no validity at all. There are tremendous simplifications in 

 the topics presented. Some simplifications shock me, let alone others 

 who would have simplified in an entirely different way. I offer no apology 

 for what has been done, for my judgment is that I have chose a reason- 

 ably good way of getting ideas and attitudes across to beginning students. 

 I would prefer this way to an appreciably more involved one required 

 for more accurate presentations. 



The quantitative, experimental point of view of the physicist and 

 chemist has been, in my judgment, their most important contribution to 

 biology. I have presented topics which seem to me to communicate this 

 quantitative, experimental point of view. Biometry has been included 

 because I think that an introduction is desirable early in the game and 

 that, for most purposes, no more than an introduction is needed by most 

 students. To say this bluntly, I think that statistical methods are highly 

 overrated, and too often serve as excuses for not doing better thought-out 

 experiments. To be fair, I must also state that professional statisticians 

 know the uses and limitations of their subject; it is the statistically ill- 

 informed scientist who tends to overrate and misuse statistics. Therefore 

 I have presented the topic from the point of view of the problems faced 

 in evaluating measurements, rather than as an exercise in application of 

 mathematics to experimentally obtained numbers. 



The chapter on physical forces and chemical bonds is placed next 

 because I believe that the molecular biology of today is only a pale be- 

 ginning of molecular studies in biology. Molecular differentiation, mo- 

 lecular neurophysiology, etc. are on the horizon. 



The physics of vision, hearing, and muscles is going to develop 

 increasingly, and in 20 years may well be the first real meeting place of 

 biology and psychology. 



Biophysical methods will continue to serve as basic equipment in the 

 experimental baggage of biological scientists. An introductory survey 

 has been written for those who would like just a quick look at the 

 methods. For those who want more depth, I have chosen to illustrate 

 with the ones which seem to me most likely to be generally applicable. 



Finally, I would like to express my gratitude to the National Science 

 Foundation for their award of a Senior Faculty Fellowship during the 

 year 1959-60. This fellowship gave me the leisure to think about bio- 

 physics, and I developed the point of view which has now led to this 

 monograph. 



Waltham, Mass. H. T. K. 



June 106.) 



