(3) Splenic Anemia.--This is an obscure form of anemia associated with great enlargement of the spleen. It is probably a distinct entity. There is decided decrease of hemoglobin and red corpuscles, with moderate leukopenia and relative lymphocytosis. Osler's fifteen cases averaged 47 per cent. hemoglobin and 3,336,357 red cells. Stained films show notable irregularities in size, shape, and staining properties only in advanced cases. Erythroblasts are uncommon. B. LEUKEMIA Except in rare instances, diagnosis is easily made from the blood alone. Two types of the disease are commonly distinguished: the _myelogenous_ and the _lymphatic_. Atypical and intermediate forms are not uncommon. Pseudoleukemia, because of its clinical similarity to lymphatic leukemia, is generally described along with leukemia. 1. Myelogenous Leukemia.--This is usually a chronic disease, although acute cases have been described. Hemoglobin and red corpuscles show decided decrease. The color-index is moderately low. Most striking is the immense increase in number of leukocytes. The count in ordinary cases varies between 100,000 and 300,000. Counts over 1,000,000 have been {209} met. During remissions, the leukocyte count may fall to normal. While these enormous leukocyte counts are equaled in no other disease, and approached only in lymphatic leukemia and extremely high-grade leukocytosis, the diagnosis, particularly during remissions, depends more upon qualitative than quantitative changes. Although all varieties are increased, the characteristic and conspicuous cell is the myelocyte. This cell never appears in normal blood; extremely rarely in leukocytosis; and never abundantly in lymphatic leukemia. In myelogenous leukemia myelocytes usually constitute more than 20 per cent. of all leukocytes. Da Costa's lowest case gave 7 per cent. The neutrophilic form is generally much more abundant than the eosinophilic. Both show considerable variations in size. Very constant also is a marked absolute, and often a relative, increase of eosinophiles and basophiles. Polymorphonuclear neutrophiles and lymphocytes are relatively decreased. [Illustration: FIG. 85.--Blood from a case of splenomedullary leukemia, stained with Ehrlich's triple stain (Jakob).] {210} The red cells show the changes characteristic of a severe secondary anemia, except that nucleated reds are commonly abundant; in fact, no other disease gives so many. They are chiefly of the normoblastic type. Megaloblasts are uncommon. Blood-plaques are generally increased. [Illustration: FIG. 86.--Blood: Lymphatic leukemia (lower section); marked leukocytosis (upper section). Stained smears. Compare types of leukocytes with Fig. 85 (from Greene's "Medical Diagnosis").] 2. Lymphatic Leukemia.--This form may be either acute or chronic. There is marked loss of hemoglobin and red corpuscles. The color-index is usually moderately low.