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ARMED FORCES INSTITUTE OF PATHOLOGY
Figure 15.—Photomicrography spreads. A. The idea of photomicrography had spread from the Medical Museum to the general hospitals, as shown by this memorandum of its use in the Douglas Hospital in Washington.
powers of magnification, or those requiring extended exposure, the beam of light was passed through a pane of greased ground glass giving a diffused "white cloud" effect or, where necessary, through an achromatic condenser placed below the stage. Photographs were made with violet light, separated from the mean white light of the sun by passing the beam through a blue ammonio-copper solution, which also aided the operator by absorbing the heat
