Ultraviolet phase contrast microscopy

Direct Inspection Direct inspection is best suited for the enumeration of planktonic organisms suspended in relatively clean water. In liquid suspensions, cell densities greater than 107 cells cm" may cause the sample to appear turbid. Quantitative enumerations using phase contrast microscopy can be done quickly using a counting chamber, which holds a known volume of fluid in a thin layer and visualization of microorganisms can be enhanced by fluorescent dyes that cause cells to light up under ultraviolet radiation [19]. 

Jhe theoretical lower limit of resolution of the light microscope is about 0.2 micron—i.e., 2000 A. This figure can be reduced in favorable circumstances by using phase-contrast or interference microscopy. Ultraviolet microscopy of coal was attempted at the Division of Coal Research, but without success owing to the opacity of coal to ultraviolet radiation. Vigorous attempts are being made to develop x-ray microscopy, and its limit of resolution is already an order better than that of the light microscope. 

Lebedeff AA (1930) Interferometre a polarisation et ses applications Rev Opt 9 385-413 Musha Y, Goring DAI (1975) Distribution of syrmgyl and guaiacyl moieties in hardwoods as indicated by ultraviolet microscopy Wood Sci Technol 9 45-58 Ross KFA (1967) Phase contrast and interference microscopy for cell biologists Edward Arnold, London, 238 pp... 

---