Page:The Armed Forces Institute of Pathology-ItsFirstCentury.djvu/57

36 young Dr. Woodward had hit upon and developed one of the great basic techniques of the pathologist. 26

Another of the indispensable tools of present-day pathology in which Woodward did pioneer work was the photographing of objects visible only under the microscope. In this work, he was assisted by Dr. Edward Curtis (fig. 14), whom Woodward described in his letter to Virchow as a patient and dexterous young man (Woodward himself was 31; Curtis was 5 years younger) with preliminary training as a microscopist, who was capable of independent investigation in pathology.

The work in photomicrography, first undertaken late in 1864 (fig. 15), was described in a report to The Surgeon General, published on 1 November 1865 as Circular No. 6, and again in the second part of the Catalogue of the Microscopical Section of the Museum, published in 1867. 27 In these early experiments with microscopic photography, the source of illumination was the sun itself, ingeniously harnessed "to insure a perfectly steady and at the same time an intense light," according to the account of the process as given in the catalogue.

The room in which the photograph was to be taken, darkened so as to dispense with a light-tight bellows, became the "camera" with a window facing south as the "shutter," through which the direct rays of the sun, caught in the mirror of a heliostat mounted outside the window, were reflected upon the plane mirror of a microscope mounted horizontally just inside the window. From the mirror, the reflected rays of the sun were thrown upon the object to be photographed, placed upon the stage of the microscope, whence the light passed through the barrel of the instrument to the object-glass where it was magnified. The magnified image was brought to a focus upon the sensitive photographic plate, mounted upon a stand which was moved back and forth along a 10-foot track provided with a scale for measurement of distances from the microscope (fig. 16). When photographs were to be made at the higher