By means of direct microscopic observation of cells in stained smears and projection of a series of color transparencies, differences in criteria used by individuals for identification of cells to be counted in Prescott-Breed smears were discovered and described. Extensive studies revealed a unique pattern of cell distribution within smears which can materially affect the outcome of a cell count depending upon the area selected for cell counting. Among other factors, variation in size of the smear was found to have a marked affect upon resultant sample count.
1This work was part of a thesis submitted by R. Schneider to the Graduate Division, University of California in partial fulfillment of the requirements for the M.S. degree.