1. An hereditary hemolytic anemia is described which is normocytic and normochromic, transmitted as a mendelian dominant and not cured by splenectomy. In the family studied, the anemia was associated but not genetically linked with brachyphalangia. Acute idiopathic porphyria may also have been associated. All anemic members were of blood group A.

2. Neither the degree of anemia nor the rate of hemolysis was favorably influenced by splenectomy.

3. Various studies of erythrocyte fragility and hemoglobin metabolism are presented.

4. Although the red cells in this anemia were more resistant to fragility tests in vitro than the red cells of hereditary spherocytosis, they were more rapidly destroyed in vivo.

5. The disease is differentiated from other hereditary and hemolytic anemias. Of the hereditary anemias, this disease seems most closely to resemble hereditary spherocytosis. Yet the differences of cellular survival in vivo and in vitro and the failure of splenectomy in hereditary nonspherocytic hemolytic anemia suggest a difference in the hemolytic mechanism.

6. The demonstration of porphobilinogen in this patient suggests a possible relationship of this hereditary hemolytic anemia to hereditary porphyria.

ACKNOWLEDGMENTS This has been the work of many hands. I especially wish to express my gratitude to Major Donald M. Goss, MSC, Miss Addelia Peterson, M.T. and Mrs. Jane C. Neff, B.S. of the Chemistry Section, Fourth Army Area Laboratory, for the many chemical determinations which were done; to Major Joseph H. Akeroyd, MSC, and Miss Constance Pollack for the tests for abnormal agglutinins, the mechanical fragility test and the cross survival transfusion studies; to Mrs. Joy Cornell for the osmotic fragility tests; to Mr. Philip Lund for many blood counts, to Dr. S. R. Henry of Crowley, Louisiana, for the x-rays of the hands of this family; and to Colonel John G. Knauer, MC, Chief of Medical Service, Brooke General Hospital for his advice, encouragement and help throughout the course of this work. Dr. Marvin Bloom suggested the diagnosis of hereditary porphyria in this case, and Dr. William Dameshek brought to my attention the significance of this finding in association with hemolytic anemia. I wish also to express my thanks to Dr. Dameshek for his valued advice in the preparation of the manuscript. All photographs were made at the Photographic Laboratory of the Pathology Service, Brooke General Hospital.