This case is reported because of the occurrence of melanuria without any evidences during life or at postmortem examination of any abnormal source of production of the pigment. CASE REPORT History. —W. S., a school boy, aged 13, born of American parents, was admitted to the New Haven Hospital on March 6, 1922, complaining of progressive enlargement of his abdomen and increasing weakness and drowsiness. His family history was not significant. His past history was unimportant except for frequent nose bleed since childhood and headaches occurring with increasing frequency for a year before admission to the hospital. Three months before admission the patient noticed that his abdomen was growing larger. At the same time he began to complain of a constant tired feeling. His mother noticed that he seemed drowsy all the time, and his teacher complained that he fell asleep at school. He also became irritable. Although his weight