1. Two Negro brothers with homozygous hemoglobin C disease are reported. In one splenectomy was performed.
2. Intraerythrocytic crystals in smears of peripheral blood were demonstrated only in the patient who had splenectomy. The crystals could not be found in re-examination of bone marrow preparations of this patient that were made prior to splenectomy.
3. Absence of the spleen may be a necessary factor for the formation of these crystals.
4. The presence of homozygous C disease is compatible with a normal life span.