Cleveland, Ohio, Sept. 5, 1907.
To the Editor:
—In The Journal, Aug. 31, 1907, page 751, Drs. Stern and Rosenberg describe a method for obtaining plastic x-ray photographs. While not denying that the method gives more pleasing effects than the ordinary x-ray photograph, it seems to me that practitioners should be warned against placing any confidence in the "plastic" appearance, which stands in no necessary relation to the actual spatial relations of the parts photographed, and in respect to these spatial relations, therefore, is always unreliable and misleading.The method is evidently a modification of a well-known photographic dodge for obtaining exaggerated relief effects resembling bas-relief. The method consists in printing a positive from any negative, of a sufficient density nearly to neutralize all contrast. The two are placed back to back, shifted slightly on each other and a print taken, thus obtaining the exaggerated relief effects. In