CHAPTER 



8 



Microscopy 



If any instrument should be given credit for contributing more than any 

 other to the development of biology as a science, that credit should go 

 to the compound microscope. The history of detailed observation of liv- 

 ing things parallels the development of magnification. Every improve- 

 ment in the art of combining lenses made it possible to see smaller struc- 

 tural units. First the cells and later the minute structures inside cells 

 were discovered. It is now possible to photograph biological structures 

 even as small as single virus particles. 



Although the microscope has contributed to biology, biology has con- 

 tributed to microscopy as well. The need for better magnifying systems 

 with which to examine parts of organisms has been the most important 

 stimulus for the opticians. 



The microscope was invented in the seventeenth century, and it did 

 not take the original microscopists long to realize the importance of a 

 number of factors, such as the quality of the lenses, the way they were 

 combined, and the type of illumination. By the end of the nineteenth 

 century, the microscope had become a precision instrument. The theo- 

 retical and practical ability of the great German scientists of the time 

 produced microscopes almost as good as any available today. The formula- 

 tion of the cell theory and the accumulation of the wealth of informa- 

 tion on the cellular structure of plants and animals occurred at this 

 time. 



The microscope permitted the biologist to see a great variety of cells, 

 combinations of cells, and parts of cells. Each living thing is slightly 

 different from any other living thing; some are composed of more-or-less 



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