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Microscopy 



I. Types of Microscopes 



The development of the microscope was one of the major advances in 

 physical instrumentation which made modern biology possible. The 

 bright-field light microscope is so familiar that it hardly seems necessary 

 to comment on it in a biophysics text. However, since about 1935, a 

 number of different forms of microscopes have appeared; these have 

 made possible far more detailed studies of the ultrastructure of cells, 

 as well as the nondestructive observation of the structures within living 

 cells. These new forms of microscopes are all specialized physical 

 instruments ; they were developed by scientists who had both an interest 

 in biology and a basic understanding of the physical principles of the 

 bright-field light microscope. 



In this chapter, the Abbe theory of the resolving power of the bright- 

 field light microscope is presented in some detail. This is followed by 

 brief descriptions of the dark-field microscope, the phase-contrast 

 microscope, the interference-contrast microscope, the polarizing micro- 

 scope, the ultraviolet and the X-ray microscopes, and the electron 

 microscope. The theories for these are essentially similar to that of 

 the bright-field light microscope. The differences and distinctive 

 features, as well as the advantages and disadvantages of each of these 



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