The effects of intravenous and intraportal infusions of hypertonic NaCl and glucose solutions on the resistance and capacitance vessels of the intact feline liver were studied. All doses infused produced vasodilation of the hepatic artery. A rough estimate would suggest that the tonicity changes equal to those seen after hemorrhage might produce an increase of arterial conductance to no less than 110% and no greater than 140% of control conductance. In response to intravenous infusions, portal flow increased to the same extent as did arterial flows. The resistance vessels were equally affected by equal osmolal loads of glucose or NaCl but the hepatic volume changes were quite different depending on the substances infused. In marked contrast with the resistance vessel response to hypertonic NaCl, the hepatic capacitance vessels did not dilate. Liver volume decreased but whether due to mild capacitance stimulation or water egress from hepatocytes is not known. Cessation of the infusion resulted in increases of hepatic volume to above control levels. Glucose produced consistent steady increases in volume that may have been associated with fluid uptake by the hepatocytes in conjunction with glucose uptake.