LIC;ilT (OPTICAL) MICROSCOPY 



1934; A. H. Linfoot, 1938; D. D. Maksutov, founder of this field of microscopy, F. Zer- 

 1944; J. D. Dyson, 1949; A. Elliot, 1950; nike, used a principle known from the study 

 and others. . of diffraction gratings. This principle was at 

 In two-mirror objectives a concave mirror first used for the testing of telescope objec- 

 is used for compensation of the aberrations tives. In 1942, the discoverer recognized its 

 of a second, convex, mirror. This principle importance for microscopy and the number 

 was refined by the application of immersion of its applications grew with every year, 

 and non-spherical systems, monochroma- In the usual microscopic observation the 

 tors, interferometers, and spectroscopes, objects are visible due to their stronger or 

 Workers in this field were Hershgorin and weaker absorption, in other words, the re- 

 associates in 1941; D. R. Burch, 1943; E. duction of the ampHtude of the light waves. 

 M. Brumberg, 1943; A. H. Bennett and In the optical system of a phase contrast 

 associates, 1948; W. E. Seeds, 1949; D. L. microscope another property of the object 

 Wood, 1950; E. R. Blout and associates material is used which consists in shifting 

 1950; D. W. Dewhirst, 1951; S. Miyata, the phase of the light waves more or less 

 1952; and many others. depending on the material constants. Upon 

 In solid objectives several reflecting sur- leaving the object the Hght does not appear 

 faces are used but the space between them to be changed in any way when observed 

 is filled with glass, or, in some cases, quartz, with the usual optical means. However, 

 Some authors feel that further development when it is combined again with another part 

 of this type of optical systems might well of the original light bundle which has suf- 

 improve the standards of the old microscope fered a fixed change of its phase by a so- 

 construction as they are followed at the called phase plate, interference occurs which 

 present time. Contributors to the field of renders visible details of the image which 

 solid objectives were D. D. Maksutov, 1932; could not be seen under a traditional micro- 

 D. G. Wynne, 1952; A. Bouwers, 1952, and scope. 



others. An especially important field of this tech- 

 Fluorescence IMicroscopy. The advan- nique is the observation of details in living 

 tage of this special field of microscopy which cells which must not be harmed or changed 

 was first mentioned in publications in 1929 by the usual methods of selective staining, 

 is the possibility of making visible or study- Those interested in the development of the 

 ing finer details of the structure of living mathematical theory and the contributions 

 protozoa or cells of tissues which might to optics of men like Descartes, Newton, 

 differ from their surroundings in fluorescing Huygens, Gauss, Hamilton, Maxwell, Seidel, 

 power under illumination by ultraviolet Helmholtz, Abbe, Gullstrand, and T. S. 

 light. This necessitates the use of special Smith are referred to articles in the proper 

 optical systems, as for example lenses made periodicals as for example published by the 

 from quartz and aluminized mirrors. Also Royal Microscopical Society in London. A 

 special optical filters were used for a better comprehensive article, 22 pages, about the 

 definition and a suitable choice of a particu- theory of optical systems was published by 

 lar section of the spectrum. Contributions M. Herzberger in Zeitschrift filr Instrumen- 

 to this field were made by M. Haitinger, P. tenkunde Vol. 52, 1932. 

 Ellinger; 1929, J. Smiles, 1933; J. Dyson, 



1949; J. R. Benford, 1947; B. K. Johnson, Historical Review 



1949; F. Brautigam and associates, 1949; In the course of the development of mi- 



C. A. Thorold, 1954, and others. croscopy from its origin to modern times, 



Phase Contrast Microscopy. The distinct periods can be recognized. They are 



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