MANY investigators have reported the gross and histologic changes which develop in the liver after relatively short periods of hepatic ischemia.1-4 With improvements in the treatment of shock and the growing interest in liver transplantation, it has become necessary to establish the direct effects of ischemia upon the hepatic structure, in order to differentiate them from changes which may be due to circulating tissue toxins or the phenomena of rejection. These baseline studies can only be done by temporary shunting of the portal-mesenteric flow to the vena cava together with reversible occlusion of the hepatic arterial supply. We have recently reported the long-term survival of experimental animals after two to four hours of hepatic ischemia produced by in situ ischemia.5 Alterations about the central sinusoidal areas which were entirely similar to those reported for hemorrhagic shock6 and liver replantation7 developed in all of the animals and