The Filament-Nonfilament Count
Since the time of Ehrlich’s epoch-making discovery of a satisfactory method of staining the white blood cells, definite and steady advances have been made in the methods and interpretations of total white blood counts and differential smears. As is well known, the white blood cells were first divided into three types — granulocytes, lymphocytes and large mononuclears. The granulocytes have been further divided into polymorphonuclear basophils, polymorphonuclear eosinophils and polymorphonuclear neutrophils. It is with the latter group that this paper is concerned chiefly.
For many years, differential counts and total counts of the white blood cells have been used as an aid in securing the clinical picture of a disease, the total number of cells and the distribution of types being used mainly as an index of the type of disease present, and the degree of its severity.
In many instances, however, the question in the physician’s or surgeon’s mind is how to explain certain incompatibilities which arise between the total leukocyte count, the differential smear, and the clinical observations in the case in question.
A distinct advance was made in 1904 and 1905 by Arneth,1 working at the Leube clinic, when he studied the changes in the nuclear structure of the neutrophils during acute infections. He made a primary division of the polymorphonuclear neutrophils into five classes, each class being recognized by the number of segmentations to the nuclei, the fifth class including those containing five or more distinct segments. He further subdivided these and also the lymphocytes and monocytes. . .