I. AVOID F R It 1 T L E S S E X P E K I M E X T S 17 



that it seems an inexcusable waste of time to attempt to discover 

 additional elements of structure in biological materials when the 

 structural details are clearly beyond the theoretical capabilities of tht 

 optical instruments employed. Nevertheless experimental efforts to 

 do so continue to be made and to be reported from time to time by 

 workers who are not aware of the limitations or who believe that 

 structural details can be demonstrated in violation of the theory. 

 Such purported structural elements invariably turn out to be diffrac- 

 tion patterns or i-elated artifacts. How much more profitable if the 

 same time were spent in other directions, perhaps with an electron 

 microscope, in which case the theoretical resolving power is several 

 hundred times greater. 



There is admittedly some danger in following too slavishly boundary 

 conditions that may be imposed by theory, particularly where theories 

 have not been well established. In research, it must be recognized 

 that "fences are built for those who cannot fly." At the same time 

 one should avoid wasting energy needlessly by flying against an im- 

 penetrable barrier. 



Knowledge of the theoretical and experimental limitations to the 

 accuracy of a research method or technique has not always been 

 readily accessible to the laboratory worker. Frequently the bound- 

 aries have been recognized only after the expenditure of valuable time 

 in a fruitless experiment. Hence, one of the chief aims of this book has 

 been the presentation of information with respect to the limitations of 

 the methods discussed in the various chapters. 



2. Instrumentation and Technique 



In discussing the research applications of electromagnetic theory, 

 Ernest O. Lawrence used to take great delight in pointing out what 

 could be done if one possessed infinite experimental skill. While con- 

 ceding that some laboratory scientists are most ingenious, I doubt if 

 any would boast of having infinite experimental skill. Consequent!}' 

 it is usually essential to take into consideration the experimental 

 limitations of a research method. Since barriers to experimental 

 progress today may not exist tomorrow, a recurring evaluation of the 

 limitations is indicated. 



Great strides in instrumentation have occurred in recent years, 

 even though the biologist's prayer for a twin-dial light source "box," 

 with one dial for wavelength and the other for intensity, has not yet 

 been answered. Waves of progress in research frequently follow the 



