In order to study the therapeutic efficiency of intravenous injections of dextrose in diphtheria, it became necessary, among other things, to note the effect of these injections on the cellular elements of the blood stream. Especially were we interested in learning if there were any changes in the size of the erythrocytes.
Renewed interest has been shown in the measurement of erythrocytes in connection with the study of various types of anemia, and numerous methods have been devised to make this determination.
METHODS OF MEASUREMENT
The methods reported in the literature may be roughly divided into two groups: (1) those which determine the diameters of erythrocytes by means of some type of ocular micrometer, and (2) those which project the images of the red cells on a screen or photographic plate, the image being magnified in projection to a size conveniently measured by means of a hand rule or calipers.
SAUDER HR, TOOMEY JA. RAPID MEASUREMENT OF RED CELLS. Am J Dis Child. 1931;41(4):823-828. doi:10.1001/archpedi.1931.01940100079010