the stomachs are removed rinsed and contents emptied into a graduated centrifuge tube the tubes are centrifuged for twenty minutes at two thousand revolutions per minute and the volume of gastric juice is recorded any sample which is obviously contaminated with feces food or blood is eliminated an aliquot of each sample is frozen for later analysis of pepsin the ph is measured and one milliliter of gastric juice is titrated with 0 1 n naoh to a ph of 7 0 7 4 the data are analyzed by analysis of variance and using the pooled error variance t comparisons are made between the groups the results obtained demonstrated 67 percent inhibition of total acid output at 1 mg kg s c 89 percent inhibition of total acid output at 2 mg kg s c and 83 percent inhibition of total acid output at 4 mg kg s c the effect of the octapeptide on gastric blood flow was established by the following procedure rats weighing 280 350 gms were used rats were anesthatized with 50 mg kg nembutal and their left jugular veins cannulated somatostatin 1 mg kg hr was infused i v in one group of rats while a second group received a saline infusion in a second experiment the octapeptide of the method of this invention 1 mg kg or saline was injected s c thirty minutes following the start of the experiment 20 u03bcci rat of 86 rbcl was injected i v the rats were killed 20 seconds later by injection of 0 5 ml nembutal the blood flow to the stomach was determined by counting 86 rb in the disected stomachs of.