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Only a few short years ago it seemed that the design of the microscope was fixed and the only refinements possible were in the mechanics of the stand. The past quarter century has witnessed a resurgence of activity as has not been seen since the great days of Abbe. Instrumental improvements have also stimulated a corresponding interest in the refinements and re-evaluation of sample preparation techniques. Frequently the use of a more sophisticated device has served to show the need of more careful preparation procedures. This is especially true of some of the newer instruments such as the electron microscope which imposes a series of very severe restrictions on the sample, such as sufficient thinness to allow electron penetration, resistance to high vacuum and electron bombardment, etc. The extent to which these limitations have been overcome is reflected in the truly amazing amount of literature on electron microscopy. The importance of technique in sample preparation and the development of the necessary skills in the proper manipulation of the instruments themselves cannot be overemphasized. Indeed it is almost a truism that not until the new microscopes enter the field and become a tool of daily use can their full possibilities be realized. Most new instruments must be “lived with” for a time before the best manner of using them is apparent. It is with the newer equipment that a broad background of experience and a familiarity with the field of microscopy in general really “pays off.” The early history of the electron microscope is an excellent example of the necessity of being familiar with what has been done before. The first commercial instruments required a great deal of maintenance on the part of the operator, and since it was an electronic device it was thought desirable to have a physicist, or at least one who knew a great deal about the science of electronics, to keep the electron microscope in operation. Then too, like most beginners in the art of microscopy, the early workers were fascinated by high magnification alone. Two incidents in our own experience serve as vivid illustrations of this tendency. A sample of a catalyst was submitted by an outside firm with the request that it be photographed with the highest possible magnification with the electron microscope. On examination, however, a 100× light micrograph with phase proved more than adequate for the purpose. The other was a paper given before the Electron Microscopy Society of America in which the electron microscope was used to study a fabric. In our opinion more pertinent information could have been obtained, not with a light microscope, but with a good photographic lens alone. The lack of knowledge of previous work led to much duplication of effort that could have been avoided had more of the workers been better acquainted with the field of general microscopy. This also had the disadvantage of separating light and electron microscopy when, after all, the electron microscope really extended the magnification range obtained with light optics. It is more and more being recognized that light and electron microscopy are supplemental disciplines.
Morehead, F. F.
American Viscose Corp., Marcus Hook, Pa.