Abstract AN OPTICAL microscope is unable to form a clear image of any object smaller than about 0.2 μ (a μ is 0.001 mm.). The electron microscope,1 utilizing a beam of electrons with much shorter wave length than visible light, is able to resolve particles less than 20 A. apart (an A. is 0.0001 μ). A beam of electrons differs from visible light in the extreme readiness with which it is stopped by all forms of matter, including air. As a result, electron microscopy must be carried out in a vacuum with desiccated and necessarily nonliving specimens. Because specimens must be sufficiently thin for beam penetration, effective histological work was delayed until practical techniques of preparing ultrathin tissue sections were developed.* The origin of contrast in the electron microscope is entirely different from that in the light microscope. For this reason, together with the increased order of References 1. References 2 to 4. 2. Wyckoff, R. W. G.: Electron Microscopy , New York, Interscience Publishers, Inc., 1949. 3. Pease, D. C., and Baker, R. F.: Sectioning Techniques for Electron Microscopy Using a Conventional Microtome , Proc. Soc. Exper. Biol. & Med. 67:470, 1948. 4. Hillier, J., and Gettner, M. D.: Sectioning of Tissue for Electron Microscopy , Science 112:520, 1950. 5. Watson, M. L.: Improved Technics for the Preparation of Tissue Sections for the Electron Microscope , Univ. Rochester, A.E.P. Quarterly Tech. Report UR-164, (Jan. 1) -March 31, 1951, Sec. 360 , p. 103. 6. Meirowsky, E., and Freeman, L. W.: Molecular Aspects of Cornification , J. Invest. Dermat. 21:83, 1953. 7. Laden, E. L.; Erickson, J. O., and Armen, D.: Electron Microscopic Study of Epidermal Prickle Cells , J. Invest. Dermat. 19:211, 1952. 8. Pease, D. C.: Electron Microscopy of Human Skin , Am. J. Anat. 89:469, 1951. 9. Gessler, A. E.; Grey, C. E.; Schuster, M. C.; Kelsch, J. J., and Richter, M. N.: Notes on the Electron Microscopy of Tissue Sections , Cancer Res. 8:513, 1948. 10. Laden, E. L.; Linden, I.; Erickson, J. O., and Armen, D.: Electron Microscopic Study of Epidermal Basal Cells and Epidermal Dermal Junction , J. Invest. Dermat. 21:37, 1953. 11. Gray, M.; Blank, H., and Rake, G.: Electron Microscopy of Normal Human Skin , J. Invest. Dermat. 19:449, 1952. 12. Gross, J., and Schmitt, F. O.: The Structure of Human Skin Collagen as Studied with the Electron Microscope , J. Exper. Med. 88:555, 1948. 13. Schmitt, F. O.; Hall, C. E., and Jakus, M. A.: Electron Microscope Investigations of the Structure of Collagen , J. Cell. & Comp. Physiol. 20:11, 1942. 14. Wyckoff, R. W. G., in Connective Tissues: Transactions of the Third Conference , edited by C. Ragan, New York, Josiah Macy, Jr., Foundation, 1952.
A.M.A. Archives of Dermatology – American Medical Association
Published: Feb 1, 1955