Lymphocytes are not very numerous as a rule; they constitute about 10 per cent, although the number may vary considerably.

The blood itself may be pale and the specific gravity lowered. Coagulation takes place slowly. The erythrocytes are decreased to about 3,000,000, the hemoglobin is diminished also, 40 per cent., color index about 0.6. Many of them are nucleated and show changes in size and shape. The normoblasts are very common, and megaloblasts are frequently seen.

The organs involved are the spleen and bone-marrow. The latter shows a marked hyperplasia, loses its yellow color and becomes dark red. Numerous nucleated erythrocytes and eosinophiles are present. The spleen is much enlarged as a result of a general hyperplasia of both the connective and lymphoid tissues. Grayish, circumscribed areas, due to the infiltration of leukocytes, may be seen. The liver is usually somewhat enlarged, and the lymph nodes may show some hyperplastic changes. Hemorrhages into the serous and mucous membranes and the retina are quite frequent. Fatty degeneration of the viscera generally occurs to some extent.

In lymphatic leukemia the lymphocytes constitute from 80 to 90 per cent of all leukocytes which number about 145,000 per cubic millimeter. The lymphocytes are usually of the small mononuclear type with a narrow rim of protoplasm around a fairly deeply staining nucleus. Sometimes the large type predominates, these latter being found more generally in acute cases and in children. In this form of leukemia, polymorphonuclear leukocytes, myelocytes, eosinophiles and mast-cells are few.

The anemia in this form is more marked than in the other, the red count at times being down to 1,500,000 with a hemoglobin per cent, of about 37. Nucleated red cells are very scarce except in the very severe cases when they may become numerous.

Fig. 129. - Lymphatic Leukemia (Cabot). l, l, l, l, l, Lymphocytes; p, polynuclear neutrophile; r, r, r, red cells.