Abstract
(1) With 25 blood slides of man and rabbit without unusually marked anisocytosis, the mean diameter of erythrocytes was measured both with the filar micrometer eyepiece and Haden-Hausser's erythrocytometer, and the values by these two methods were compared.
(2) The error of Haden-Hausse's erythrocytometer was less than 0.2μ in the range covering from 6.5 to 9.5μ.
(3) Taking the ease and simplicity of the procedure into consideration the error 0.2μ is relatively insignificant, and this apparatus can be used for the estimation of the mean diameter of erythrocytes with profit.
