MATERIALS AND METHODS

Subjects.—Liver tissue of 52 Japanese (35 males, 17 females) aged 21 to 79 years was obtained at the beginning of upper abdominal surgery. The Ss selected for study showed no abnormality in routine liver function tests, and the liver samples were microscopically free of pathological conditions. The biopsy was made 15 min. after starting of laparotomy, approximately 10: 00 am, under semiclosed endotracheal anesthesia by fluothane, nitrous oxide, and oxygen mixture. The patients were fasted for 15 hours preceding the operation. Small blocks of the tissues were fixed for 1 hour in 1% osmium tetroxide solution buffered with veronal acetate, pH 7.4, and 0.13 M sucrose, dehydrated in alcohol, and embedded in Epon 812 (Luft's method). Sections were cut with a JUM-5A or LKB ultramicrotome using glass knives, stained with uranyl acetate and