WHITE CORPUSCLES The blood contains about i i,000 white corpuscles per cubic millimetre ; thus there is only one white corpuscle to 400-500 red. The number varies within considerable limits.
The white corpuscles in blood are of at least five kinds ; the classical classification depends upon (I) whether the protoplasm of the cells contains granules—those in which it does not being called hyaline and (2) among the granular ones whether the granules stain with acid dyes such as eosin (acidophil, eosinophil) or basic dyes such as methylene blue (basophil) (see PLATE). These five cells are given many different names:— I. Small hyaline, lymphocyte.
2. Large hyaline, mononuclear, monocyte.
3. Fine granular eosinophil, neutrophil, polynuclear, polymor phonuclear.
4. Coarsely granular eosinophil, eosinophil.
5. Basophil, mast cell.
I. The lymphocyte is about 6.52 in diameter. It has a large spherical nucleus which is surrounded by a small rim of clear protoplasm. It forms normally about 20-25% of the white cor puscles. It is not amoeboid, nor is it phagocytic (i.e., it does not ingest other cells). These cells are formed in the lymphatic glands.
2. The large hyaline cell may really include two quite different cells of similar appearance, one of which is a larger edition of the lymphocyte, the other being the monocyte proper. The nucleus is spherical or kidney shaped. The protoplasm is larger in amount than in the lymphocyte. About 4% of the white cells in the blood are large hyaline cells. The monocyte is highly amoeboid and phagocytic, its tendrils being long and delicate.
The relation of the monocyte to certain other cells in the body is a matter of much discussion. It has been seen in cultures to ingest large quantities of other cells taking on the appearance of a cell known as the clasmocyte. Also there is similar evidence of the epitheloid cells common in tuberculous lesions being merely monocytes which have wandered from the blood in special guise. Some authors go much farther, alleging that the monocyte can turn into other cells ; e.g., connective tissue cells, and that these can return to become monocytes once more. Such a view involves the general conception of a cell being at one moment the cell of one type of tissue, at another that of another and is to be treated with great reserve.
3. The Polymorphonuclear Cell.—This contains a nucleus consisting usually of several lobes joined by threads. The proto plasm contains numerous fine granules which stain with eosin. The cell is about i o,u in diameter. It is highly amoeboid and phagocytic and forms about 7o% of the total number of leucocytes.
The polymorphonuclear cells wander into infected tissues in great numbers, their presence forming an important factor in the processes of shutting off foci of infection and of repair of tissue (see PATHOLOGY). These cells are formed in the red marrow of the bones.
5. The Basophil Cell.—This possesses a spherical nucleus and the protoplasm contains a small number of granules staining deeply with basic dyes. It forms about 0.5% of the white cells.
As well as the red and white corpuscles there are in the blood certain formed elements of a much more obscure character. Much smaller than the corpuscles they form minute rods or plates. In the frog they appear to be nucleated. Their function is not completely understood.