Beginnings of Microscopy

Until about 1660 A.D. all knowledge of the form, structure and life processes of plants and animals was narrowly restricted to what could be seen with the naked (or very feebly assisted) human eye. Microorganisms were merely fabulous monsters. Visual limitations 

Unaided human vision fails to see objects less than about 100 p, (0.004 or 1/254 inch) in diameter or to perceive as separate objects 

TABLE 2.1 SOME LINEAR MEASURES COMMONLY USED IN MICROBIOLOGY 

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