Introduction
A significant advance in evaluation of gastric function occurred in 1943 when the quantitative measurement of the fasting gastric secretion of acid was first applied clinically.2 In the first papers fasting gastric hypersecretion was realized to be the major factor in the genesis of duodenal ulcer. Gastric output was measured by recording the volume aspirated from the stomach over a known (12-hour) length of time. The concentration of acid in this aspirate was then determined and expressed as Free Acidity in clinical units. One clinical unit was that amount of acid neutralized by 1 cc 0.1 N NaOH.Later gastric output was described in milligrams,6 millimols,1 and finally milliequivalents.3 Total gastric output of acid is now commonly expressed in terms of milliequivalents, and over a period of years a set of normal values for various conditions has been determined.4 These are for the 12-hour