The vascular readjustments in compensation for a greatly reduced blood bulk affect the service rendered by the blood to the gastrointestinal tract and liver far less than they do that to the skin and muscles. Into these latter tissues india ink is carried almost not at all, whereas it circulates in quantity through the capillaries of the bowel and liver. Evidently vaso-constriction is much less effective in these viscera. Nowhere in them does one find a patchy ischemia like that so wide-spread in the peripheral tissues. Blood service is maintained to the same extent everywhere throughout the liver even when one of its two sources (hepatic artery or portal vein) is obstructed, and the intrahepatic blood pressure brought very low.
A pronounced patchy ischemia of the stomach and large bowel can be induced by intravenous injection into normal animals of sufficient epinephrin to cause the systemic blood pressure to mount to an abnormally high level. Pituitrin used in the same way has a greater effect; blood service to the organs mentioned may be completely abolished by means of it. In both instances, though, service to the small gut and liver is still excellently and evenly maintained.