CHAPTER 



5 



Selection of Techniques 



Most of the modern experiments in biology employ instruments, tools, 

 or techniques assembled from the various physical sciences. Usually 

 several different methods or instruments are available, and the investiga- 

 tor must make a choice. Sometimes it is not easy to choose. 



Of course the techniques to be used in a research project must be 

 suitable and related to the problem. The most elaborate set of instruments 

 is useless if it does not measure the right thing. 



Physical science has placed many instruments at the disposal of the 

 biologists— some simple, some extremely complex. Several features of 

 these are noted in the following sections, and several general methods 

 are described in detail in the chapters which follow. The method to be 

 chosen is the one that gives the most precise and reliable information 

 with the least difficulty and expense. 



Many papers in the literature contain descriptions of complicated 

 assemblies of parts put together for use in rather simple experiments. 

 If such an instrument (or combination of instruments) is unique and 

 expensive, or if it depends on principles not commonly used, it is likely 

 to be called "elegant." Many of the elegant instruments are constructed 

 in the laboratories where they are used. Some people, who are born 

 gadgeteers, do all their experimenting with such instruments. It is fun and 

 stimulating to the imagination. Papers describing work done by such 

 instruments are impressive, we must admit. Frequently these instruments 

 offer the only way to make a certain kind of measurement. 



Not all experimental research requires elaborate instrumentation, how- 

 ever. Even the most impassioned gadgeteer, with pliers for hands and 



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