1. Intravenous injections of alkaline hematin in the rabbit produce an anemia the severity of which is proportional to the amount of hematin injected and the susceptibility of the animal. 2. Hemoglobinemia is an occasional consequence of hematin poisoning. 3. The leucocytes in hematin intoxication are usually increased in number and are always characterized by a high percentage of large mononuclear cells and by pigmented phagocytes. 4. The platelets are markedly reduced by alkaline hematin and ultimately a prolongation of the coagulation time of the blood and of the bleeding time results. 5. The anemia, the hemoglobinemia, the high percentage of large mononuclear leucocytes, the destruction of platelets, and the tendency to hemorrhage in malaria are all influenced by the malarial pigment, hematin.